1824 lines
51 KiB
Markdown
1824 lines
51 KiB
Markdown
---
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aliases:
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- nec-311
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tags:
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- authorship/other
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- destiny/uncertain
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- exclude-from-word-count
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- status/draft
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- topic/construction/electrical
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- type/media/reference
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title: Article 311 Medium Voltage Conductors and Cable
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---
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# Article 311 Medium Voltage Conductors and Cable
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## Part I. General
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### 311.1 Scope.
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This article covers the use, installation, construction specifications, and ampacities for Type MV medium voltage conductors and cable.
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### 311.2 Definitions.
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The definitions in this section shall apply within this article and throughout the Code.
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#### Electrical Ducts.
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Electrical conduits, or other raceways round in cross section, that are suitable for use underground or embedded in concrete.
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#### Medium Voltage Cable, Type MV.
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A single or multiconductor solid dielectric insulated cable rated 2001 volts up to and including 35,000 volts, nominal.
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#### Thermal Resistivity.
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As used in this Code, the heat transfer capability through a substance by conduction.
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> [!info] Informational Note:
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> Thermal resistivity is the reciprocal of thermal conductivity and is designated Rho, which is expressed in the units °C-cm/W.
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### 311.6 Listing Requirements.
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Type MV cables and associated fittings shall be listed.
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## Part II. Construction Specifications
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### 311.10 Constructions and Applications.
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Type MV cables shall comply with the applicable provisions in 311.10(A) through (C).
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#### 311.10(A) Conductor Application and Insulation.
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Conductor application and insulation shall comply with Table 311.10(A).
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##### Table 311.10(A) Conductor Application and Insulation Rated 2001 Volts and Higher
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| Trade Name | Type Letter | Maximum Operating Temperature | Application Provision | Insulation | Outer Covering |
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|:-------------------------------:|:-------------------:|:-----------------------------:|:---------------------:|:------------------------------:|:------------------------:|
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| Medium voltage solid dielectric | MV-90 | 90°C | Dry or wet locations | Thermoplastic or thermosetting | Jacket, sheath, or armor |
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| | MV-105<sup>\*</sup> | 105°C | | | |
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<sup>\*</sup>Where design conditions require maximum conductor temperatures above 90°C.
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#### 311.10(B) Thickness of Insulation and Jacket for Nonshielded Insulated Conductors.
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Thickness of insulation and jacket for nonshielded solid dielectric insulated conductors rated 2001 volts to 5000 volts
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shall comply with Table 311.10(B).
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##### Table 311.10(B) Thickness of Insulation and Jacket for Nonshielded Solid Dielectric Insulated Conductors Rated 2001 Volts to 5000 Volts
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Overall Insulation Jacket
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Dry Locations Single Conductor Without Jacket 8 2.79mm (110mils)
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Dry Locations Single Conductor Without Jacket 6 2.79mm (110mils)
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Dry Locations Single Conductor Without Jacket 4–2 2.79mm (110mils)
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Dry Locations Single Conductor Without Jacket 1–2/0 2.79mm (110mils)
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Dry Locations Single Conductor Without Jacket 3/0–4/0 2.79mm (110mils)
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Dry Locations Single Conductor Without Jacket 213–500 3.05mm (120mils)
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Dry Locations Single Conductor Without Jacket 501–750 3.30mm (130mils)
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Dry Locations Single Conductor Without Jacket 751–1000 3.30mm (130mils)
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Dry Locations Single Conductor Without Jacket 1001–1250 3.56mm (140mils)
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Dry Locations Single Conductor Without Jacket 1251–1500 3.56mm (140mils)
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Dry Locations Single Conductor Without Jacket 1501–2000 3.56mm (140mils)
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Dry Locations Single Conductor 8 2.29mm (90mils) 0.76mm (30mils)
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Dry Locations Single Conductor 6 2.29mm (90mils) 0.76mm (30mils)
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Dry Locations Single Conductor 4–2 2.29mm (90mils) 1.14mm (45mils)
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Dry Locations Single Conductor 1–2/0 2.29mm (90mils) 1.14mm (45mils)
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Dry Locations Single Conductor 3/0–4/0 2.29mm (90mils) 1.65mm (65mils)
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Dry Locations Single Conductor 213–500 2.29mm (90mils) 1.65mm (65mils)
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Dry Locations Single Conductor 501–750 2.29mm (90mils) 1.65mm (65mils)
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Dry Locations Single Conductor 751–1000 2.29mm (90mils) 1.65mm (65mils)
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Dry Locations Single Conductor 1001–1250 2.92mm (115mils) 1.65mm (65mils)
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Dry Locations Single Conductor 1251–1500 2.92mm (115mils) 2.03mm (80mils)
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Dry Locations Single Conductor 1501–2000 2.92mm (115mils) 2.03mm (80mils)
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Wet or Dry Locations Single Conductor 8 3.18mm (125mils) 2.03mm (80mils)
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Wet or Dry Locations Single Conductor 6 3.18mm (125mils) 2.03mm (80mils)
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Wet or Dry Locations Single Conductor 4–2 3.18mm (125mils) 2.03mm (80mils)
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Wet or Dry Locations Single Conductor 1–2/0 3.18mm (125mils) 2.03mm (80mils)
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Wet or Dry Locations Single Conductor 3/0–4/0 3.18mm (125mils) 2.41mm (95mils)
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Wet or Dry Locations Single Conductor 213–500 3.56mm (140mils) 2.79mm (110mils)
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Wet or Dry Locations Single Conductor 501–750 3.94mm (155mils) 3.18mm (125mils)
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Wet or Dry Locations Single Conductor 751–1000 3.94mm (155mils) 3.18mm (125mils)
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Wet or Dry Locations Single Conductor 1001–1250 4.32mm (170mils) 3.56mm (140mils)
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Wet or Dry Locations Single Conductor 1251–1500 4.32mm (170mils) 3.56mm (140mils)
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Wet or Dry Locations Single Conductor 1501–2000 4.32mm (170mils) 3.94mm (155mils)
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Wet or Dry Locations Multiconductor Insulation* 8 2.29mm (90mils)
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Wet or Dry Locations Multiconductor Insulation* 6 2.29mm (90mils)
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Wet or Dry Locations Multiconductor Insulation* 4–2 2.29mm (90mils)
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Wet or Dry Locations Multiconductor Insulation* 1–2/0 2.29mm (90mils)
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Wet or Dry Locations Multiconductor Insulation* 3/0–4/0 2.29mm (90mils)
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Wet or Dry Locations Multiconductor Insulation* 213–500 2.29mm (90mils)
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Wet or Dry Locations Multiconductor Insulation* 501–750 2.29mm (90mils)
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Wet or Dry Locations Multiconductor Insulation* 751–1000 2.29mm (90mils)
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Wet or Dry Locations Multiconductor Insulation* 1001–1250 2.92mm (115mils)
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Wet or Dry Locations Multiconductor Insulation* 1251–1500 2.92mm (115mils)
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Wet or Dry Locations Multiconductor Insulation* 1501–2000 3.56mm (140mils)
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*Under a common overall covering such as a jacket, sheath, or armor.
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Conductor Size (AWG or kcmil)
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25,001–28,000 Volts 28,001–35,000 Volts
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100 Percent Insulation Level
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133 Percent Insulation Level
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173 Percent Insulation Level
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100 Percent Insulation Level
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133 Percent Insulation Level
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173 Percent Insulation
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Level mm mils mm mils mm mils mm mils mm mils mm mils
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1 7.11 280 8.76 345 11.30 445 — — — — — —
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1/0–2000 7.11 280 8.76 345 11.30 445 8.76 345 10.67 420 14.73 580
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#### 311.10(C) Thickness of Insulation for Shielded Insulated Conductors.
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Thickness of insulation for shielded solid dielectric insulated conductors rated 2001 volts to 35,000 volts shall comply with Table 311.10(C) and 311.10(C)(1) through (C)(3).
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##### 311.10(C)(1) 100 Percent Insulation Level.
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Cables shall be permitted to be applied
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where the system is provided with relay protection
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such that ground faults will be cleared as rapidly as possible but, in any case, within 1 minute.
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These cables are applicable to cable installations that are on grounded systems
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and shall be permitted to be used on other systems
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provided the above clearing requirements are met
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in completely de-energizing the faulted section.
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##### 311.10(C)(2) 133 Percent Insulation Level.
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Cables shall be permitted to be applied
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in situations where the clearing time requirements
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of the 100 percent level category cannot be met
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and the faulted section will be de-energized in a time not exceeding 1 hour.
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Cable shall be permitted to be used in 100 percent insulation level applications
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where the installation requires additional insulation.
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##### 311.10(C)(3) 173 Percent Insulation Level.
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Cables shall be permitted to be applied under all of the following conditions:
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* (1) In industrial establishments where the conditions of maintenance and supervision ensure only qualified persons service the installation
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* (2) Where the fault clearing time requirements of the 133 percent level category cannot be met
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* (3) Where an orderly shutdown is required to protect equipment and personnel
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* (4) Where the faulted section will be de-energized in an orderly shutdown
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Cables shall be permitted to be used in 100 percent or 133 percent insulation level applications where the installation requires additional insulation.
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##### Table 311.10(C) Thickness of Insulation for Shielded Solid Dielectric Insulated Conductors Rated 2001 Vol
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2001–5000 Volts 5001–8000 Volts 8001–15,000 Volts
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Conductor
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Size
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(AWG or kcmil)
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100
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Percent
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Insulation
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Level
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100
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Percent
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Insulation
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Level
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133
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Percent
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Insulation
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Level
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173
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Percent
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Insulation
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Level
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100
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Percent
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Insulation
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Level
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133
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Percent
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Insulation
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Level
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173
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Percent
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Insulation
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Level
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100
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Percen
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Insulat
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Leve mm mils mm mils mm mils mm mils mm mils mm mils mm mils mm m
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8 2.29 90 — — — — — — — — — — — — — —
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6–4 2.29 90 2.92 115 3.56 140 4.45 175 — — — — — — — —
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2 2.29 90 2.92 115 3.56 140 4.45 175 4.45 175 5.59 220 6.60 260 — —
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1 2.29 90 2.92 115 3.56 140 4.45 175 4.45 175 5.59 220 6.60 260 6.60 2
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1/0–2000 2.29 90 2.92 115 3.56 140 4.45 175 4.45 175 5.59 220 6.60 260 6.60 2
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### 311.12 Conductors.
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#### 311.12(A) Minimum Size of Conductors.
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The minimum size of conductors shall be as shown in Table 311.12(A), except as permitted elsewhere in this Code.
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##### Table 311.12(A) Minimum Size of Conductors
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| Conductor Voltage Rating (Volts) | Minimum Conductor Size (AWG) Copper, Aluminum, or Copper-Clad Aluminum |
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| -------------------------------- | ---------------------------------------------------------------------- |
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| 2001–5000 | 8 |
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| 5001–8000 | 6 |
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| 8001–15,000 | 2 |
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| 15,001–28,000 | 1 |
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| 28,001–35,000 | 1/0 |
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#### 311.12(B) Conductor Material.
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Conductors shall be of aluminum, copper-clad aluminum, or copper unless otherwise specified.
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#### 311.12(C) Stranded Conductors.
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Where installed in raceways, conductors not specifically permitted or required elsewhere in this Code to be solid shall be stranded.
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### 311.14 Conductor Identification.
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Conductors that are intended for use as ungrounded conductors, whether used as a single conductor or in multiconductor cables, shall be finished to be clearly distinguishable from grounded and grounding conductors. Distinguishing markings shall not conflict in any manner with the surface markings required by 311.16(B)(1). Branch-circuit ungrounded conductors shall be identified in accordance with 210.5(C). Feeders shall be identified in accordance with 215.12.
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### 311.16 Marking.
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#### 311.16(A) Required Information.
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All conductors and cables shall be marked to indicate the following information, using the applicable method described in 311.16(B):
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* (1) The maximum rated voltage
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* (2) The proper type letter or letters for the type of wire or cable as specified elsewhere in this Code
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* (3) The manufacturer’s name, trademark, or other distinctive marking by which the organization responsible for the product can be readily identified
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* (4) The AWG size or circular mil area
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> [!info] Informational Note:
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> See Chapter 9, Table 8, Conductor Properties, for conductor area expressed in SI units for conductor sizes specified in AWG or circular mil area.
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#### 311.16(B) Method of Marking.
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One or more of the methods in 311.16(B)(1) through (B)(4) shall be used for marking of cable.
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##### 311.16(B)(1) Surface Marking.
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Cables shall be durably marked on the surface. The AWG size or circular mil area shall be repeated at intervals not exceeding 610 mm (24 in.). All other markings shall be repeated at intervals not exceeding 1.0 m (40 in.).
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##### 311.16(B)(2) Marker Tape.
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Metal-covered multiconductor cables shall employ a marker tape located within the cable and along its complete length.
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##### 311.16(B)(3) Tag Marking.
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Metal-covered, single-conductor cables shall be marked by means of a printed tag attached to the reel.
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##### 311.16(B)(4) Optional Marking of Wire Size.
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The information required in 311.16(A)(4) shall be permitted to be marked on the surface of the individual insulated conductors for multiconductor Type MC cable.
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#### 311.16(C) Optional Markings.
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Cables shall be permitted to be marked to indicate special characteristics of the cable materials, such as limited smoke and sunlight resistance.
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## Part III. Installation
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### 311.30 Installation.
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Type MV cable shall be installed, terminated, and tested by qualified persons.
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> [!info] Informational Note No. 1:
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> Information about accepted industry practices and installation procedures for medium-voltage cable are described in ANSI/NECA/NCSCB 600, Standard for Installing and Maintaining Medium-Voltage Cable, and in IEEE 576, Recommended Practice for Installation, Termination, and Testing of Insulated Power Cables as Used in Industrial and Commercial Applications.
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> [!info] Informational Note No. 2:
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> Where medium-voltage cable is used for dc circuits, low frequency polarization can create hazardous voltages. When handling the cable these voltages may be present or may develop on dc stressed cable while the circuit is energized.
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Solidly grounding the cable prior to contacting, cutting or disconnecting cables in dc circuits is a method to discharge these voltages.
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### 311.32 Uses Permitted.
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Type MV cable shall be permitted for use on power systems rated up to and including 35,000 volts, nominal, as follows:
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* (1) In wet or dry locations.
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* (2) In raceways.
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* (3) In cable trays, where identified for the use, in accordance with 392.10, 392.20(B), (C), and (D), 392.22(C), 392.30(B)(1), 392.46, 392.56, and 392.60. Type MV cable that has an overall metallic sheath or armor, complies with the requirements for Type MC cable, and is identified as “MV or MC” shall be permitted to be installed in cable trays in accordance with 392.10(B)(2).
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* (4) In messenger-supported wiring in accordance with Part II of Article 396.
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* (5) As exposed runs in accordance with 300.37. Type MV cable that has an overall metallic sheath or armor, complies with the requirements for Type MC cable, and is identified as “MV or MC” shall be permitted to be installed as exposed runs of metal-clad cable in accordance with 300.37.
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* (6) Corrosive conditions where exposed to oils, greases, vapors, gases, fumes, liquids, or other substances having a deleterious effect on the conductor or insulation shall be of a type suitable for the application.
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* (7) Conductors in parallel in accordance with 310.10(G).
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* (8) Type MV cable used where exposed to direct sunlight shall be identified for the use.
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> [!info] Informational Note:
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> The “uses permitted” is not an all-inclusive list.
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### 311.36 Direct-Burial Conductors.
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Type MV conductors and cables used for direct burial applications shall be shielded, identified for such use, and installed in accordance with 300.50.
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> [!important] Exception No. 1:
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> Nonshielded multiconductor cables rated 2001 volts to 2400 volts shall be permitted if the cable has an overall metallic sheath or armor. The metallic shield, sheath, or armor shall be connected to a grounding electrode conductor, a grounding busbar, or a grounding electrode.
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> [!important] Exception No. 2:
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> Airfield lighting cable used in series circuits that are rated up to 5000 volts and are powered by regulators shall be permitted to be nonshielded.
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> [!info] Informational Note to Exception No. 2:
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> Federal Aviation Administration (FAA) Advisory Circulars (ACs) provide additional practices and methods for airport lighting.
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### 311.40 Support.
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Type MV cable terminated in equipment or installed in pull boxes or vaults shall be secured and supported by metallic or nonmetallic supports suitable to withstand the weight by cable ties listed and identified for securement and support, or other approved means, at intervals not exceeding 1.5 m (5 ft) from terminations or a maximum of 1.8 m (6 ft) between supports.
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### 311.44 Shielding.
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Nonshielded, ozone-resistant insulated conductors with a maximum phase-to-phase voltage of 5000 volts shall be permitted in Type MC cables in industrial establishments where the conditions of maintenance and supervision ensure that only qualified persons service the installation. For other establishments, solid dielectric insulated conductors operated above 2000 volts in permanent installations shall have ozone-resistant insulation and shall be shielded. All metallic insulation shields shall be connected to a grounding electrode conductor, a grounding busbar, an equipment grounding conductor, or a grounding electrode.
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> [!info] Informational Note:
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> The primary purposes of shielding are to confine the voltage stresses to the insulation, dissipate insulation leakage current, drain off the capacitive charging current, and carry ground-fault current to facilitate operation of ground-fault protective devices in the event of an electrical cable fault.
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> [!important] Exception No. 1:
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> Nonshielded insulated conductors listed by a qualified testing laboratory shall be permitted for use up to 2400 volts under the following conditions:
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>
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> * (1) Conductors shall have insulation resistant to electric discharge and surface tracking, or the insulated conductor(s) shall be covered with a material resistant to ozone, electric discharge, and surface tracking.
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>
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> * (2) Where used in wet locations, the insulated conductor(s) shall have an overall nonmetallic jacket or a continuous metallic sheath.
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>
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> * (3) Insulation and jacket thicknesses shall be in accordance with Table 311.10(B).
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> [!important] Exception No. 2:
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> Nonshielded insulated conductors listed by a qualified testing laboratory shall be permitted for use up to 5000 volts to replace existing nonshielded conductors, on existing equipment in industrial establishments only, under the following conditions:
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>
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||
> * (1) Where the condition of maintenance and supervision ensures that only qualified personnel install and service the installation.
|
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>
|
||
> * (2) Conductors shall have insulation resistant to electric discharge and surface tracking, or the insulated conductor(s) shall be covered with a material resistant to ozone, electric discharge, and surface tracking.
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||
>
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||
> * (3) Where used in wet locations, the insulated conductor(s) shall have an overall nonmetallic jacket or a continuous metallic sheath.
|
||
>
|
||
> * (4) Insulation and jacket thicknesses shall be in accordance with Table 311.10(B).
|
||
|
||
> [!info] Informational Note:
|
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> Relocation or replacement of equipment may not comply with the term existing as related to this exception.
|
||
|
||
> [!important] Exception No. 3:
|
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> Where permitted in 311.36, Exception No. 2.
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## Part IV. Ampacities
|
||
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### 311.60 Ampacities of Conductors.
|
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#### 311.60(A) General.
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##### 311.60(A)(1) Tables or Engineering Supervision.
|
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|
||
Ampacities for solid dielectric-insulated conductors
|
||
shall be permitted to be determined by tables
|
||
or under engineering supervision,
|
||
as provided in 311.60(B) and (C).
|
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|
||
The ampacity of Type MV cable installed in cable tray
|
||
shall be determined in accordance with
|
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[[nfpa-70_392_cable-tray#392.80(B) Ampacity of Type MV and Type MC Cables (2001 Volts or Over) in Cable Trays.|392.80(B)]].
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|
||
##### 311.60(A)(2) Selection of Ampacity.
|
||
|
||
Where more than one calculated or tabulated ampacity could apply for a given circuit length,
|
||
the lowest value shall be used.
|
||
|
||
> [!important] Exception:
|
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> Where different ampacities apply to portions of a circuit, the higher ampacity shall be permitted to be used if the total portion(s) of the circuit with the lower ampacity does not exceed the lesser of 3.0 m (10 ft) or 10 percent of the total circuit.
|
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|
||
> [!info] Informational Note:
|
||
> See 110.40 for conductor temperature limitations due to termination provisions.
|
||
|
||
#### 311.60(B) Engineering Supervision.
|
||
|
||
Under engineering supervision, conductor ampacities shall be permitted to be calculated by using the following general equation:
|
||
|
||
##### Equation 311.60(B)
|
||
|
||
$$
|
||
I = \sqrt{ \frac{ T_{c} - ( T_{a} + \Delta T_{d} ) }{R_{dc} ( 1 + Y_{c}) R_{ca}} } \times 10^3~\text{amperes}
|
||
$$
|
||
|
||
where:
|
||
* $T_{c}$ conductor temperature (°C)
|
||
* $T_{a}$ ambient temperature (°C)
|
||
* $\Delta T_{d}$ dielectric loss temperature rise
|
||
* $R_{dc}$ dc resistance of conductor at temperature, $T_{c}$
|
||
* $Y_{c}$ component ac resistance resulting from skin effect and proximity effect
|
||
* $R_{ca}$ effective thermal resistance between conductor and surrounding ambient
|
||
|
||
> [!info] Informational Note:
|
||
> The dielectric loss temperature rise ($\Delta T_{d}$)
|
||
> is negligible for single circuit extruded dielectric cables rated below 46 kilovolts.
|
||
|
||
#### 311.60(C) Tables.
|
||
|
||
Ampacities for conductors rated 2001 volts to 35,000 volts shall be as specified in Table 311.60(C)(67) through Table 311.60(C)(86).
|
||
|
||
Ampacities for ambient temperatures other than those specified in the ampacity tables shall be corrected in accordance with 311.60(D)(4).
|
||
|
||
> [!info] Informational Note No. 1:
|
||
> For ampacities calculated in accordance with 311.60(A), reference IEEE 835, Standard Power Cable Ampacity Tables, and the references therein for availability of all factors and constants.
|
||
|
||
> [!info] Informational Note No. 2:
|
||
> Ampacities provided by this section do not take voltage drop into consideration.
|
||
> See 210.19(A), Informational Note No. 4, for branch circuits and 215.2(A), Informational Note No. 2, for feeders.
|
||
|
||
##### Table 311.60(C)(67) Ampacities of Insulated Single Copper Conductor Cables Triplexed in Air
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 65 74 — —
|
||
6 90 99 100 110
|
||
4 120 130 130 140
|
||
2 160 175 170 195
|
||
1 185 205 195 225
|
||
1/0 215 240 225 255
|
||
2/0 250 275 260 295
|
||
3/0 290 320 300 340
|
||
4/0 335 375 345 390
|
||
250 375 415 380 430
|
||
350 465 515 470 525
|
||
500 580 645 580 650
|
||
750 750 835 730 820
|
||
1000 880 980 850 950
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(68) Ampacities of Insulated Single Aluminum Conductor Cables Triplexed in Air
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 50 57 — —
|
||
6 70 77 75 84
|
||
4 90 100 100 110
|
||
2 125 135 130 150
|
||
1 145 160 150 175
|
||
1/0 170 185 175 200 d
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
2/0 195 215 200 230
|
||
3/0 225 250 230 265
|
||
4/0 265 290 270 305
|
||
250 295 325 300 335
|
||
350 365 405 370 415
|
||
500 460 510 460 515
|
||
750 600 665 590 660
|
||
1000 715 800 700 780
|
||
|
||
Note: Refer to 311.60(E) for basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(69) Ampacities of Insulated Single Copper Conductor Isolated in Air
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–15,000 Volts Ampacity
|
||
15,001–35,000 Volts
|
||
|
||
Ampacity
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
8 83 93 — — — —
|
||
6 110 120 110 125 — —
|
||
4 145 160 150 165 — —
|
||
2 190 215 195 215 — —
|
||
1 225 250 225 250 225 250
|
||
1/0 260 290 260 290 260 290
|
||
2/0 300 330 300 335 300 330
|
||
3/0 345 385 345 385 345 380
|
||
4/0 400 445 400 445 395 445
|
||
250 445 495 445 495 440 490
|
||
350 550 615 550 610 545 605
|
||
500 695 775 685 765 680 755
|
||
750 900 1000 885 990 870 970
|
||
1000 1075 1200 1060 1185 1040 1160
|
||
1250 1230 1370 1210 1350 1185 1320
|
||
1500 1365 1525 1345 1500 1315 1465
|
||
1750 1495 1665 1470 1640 1430 1595
|
||
2000 1605 1790 1575 1755 1535 1710
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(70) Ampacities of Insulated Single Aluminum Conductor Isolated in Air
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–15,000 Volts Ampacity
|
||
15,001–35,000 Volts
|
||
|
||
Ampacity
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
8 64 71 — — — —
|
||
6 85 95 87 97 — —
|
||
4 115 125 115 130 — —
|
||
2 150 165 150 170 — —
|
||
1 175 195 175 195 175 195
|
||
1/0 200 225 200 225 200 225
|
||
2/0 230 260 235 260 230 260
|
||
3/0 270 300 270 300 270 300
|
||
4/0 310 350 310 350 310 345
|
||
250 345 385 345 385 345 380
|
||
350 430 480 430 480 430 475
|
||
500 545 605 535 600 530 590
|
||
750 710 790 700 780 685 765
|
||
1000 855 950 840 940 825 920
|
||
1250 980 1095 970 1080 950 1055
|
||
1500 1105 1230 1085 1215 1060 1180
|
||
1750 1215 1355 1195 1335 1165 1300
|
||
2000 1320 1475 1295 1445 1265 1410
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(71) Ampacities of an Insulated Three-Conductor Copper Cable Isolated in Air
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 59 66 — —
|
||
6 79 88 93 105
|
||
4 105 115 120 135
|
||
2 140 154 165 185
|
||
1 160 180 185 210
|
||
1/0 185 205 215 240
|
||
2/0 215 240 245 275
|
||
3/0 250 280 285 315
|
||
4/0 285 320 325 360
|
||
250 320 355 360 400
|
||
350 395 440 435 490
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
500 485 545 535 600
|
||
750 615 685 670 745
|
||
1000 705 790 770 860
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(72) Ampacities of an Insulated Three-Conductor Aluminum Cable Isolated in Air
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 46 51 — —
|
||
6 61 68 72 80
|
||
4 81 90 95 105
|
||
2 110 120 125 145
|
||
1 125 140 145 165
|
||
1/0 145 160 170 185
|
||
2/0 170 185 190 215
|
||
3/0 195 215 220 245
|
||
4/0 225 250 255 285
|
||
250 250 280 280 315
|
||
350 310 345 345 385
|
||
500 385 430 425 475
|
||
750 495 550 540 600
|
||
1000 585 650 635 705
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(73) Ampacities of an Insulated Triplexed or Three Single-Conductor Copper Cables in Isolated Conduit in Air
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 55 61 — —
|
||
6 75 84 83 93
|
||
4 97 110 110 120
|
||
2 130 145 150 165
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
1 155 175 170 190
|
||
1/0 180 200 195 215
|
||
2/0 205 225 225 255
|
||
3/0 240 270 260 290
|
||
4/0 280 305 295 330
|
||
250 315 355 330 365
|
||
350 385 430 395 440
|
||
500 475 530 480 535
|
||
750 600 665 585 655
|
||
1000 690 770 675 755
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(74) Ampacities of an Insulated Triplexed or Three Single-Conductor Aluminum Cables in Isolated Conduit in Air
|
||
|
||
Conductor Size (AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 43 48 — —
|
||
6 58 65 65 72
|
||
4 76 85 84 94
|
||
2 100 115 115 130
|
||
1 120 135 130 150
|
||
1/0 140 155 150 170
|
||
2/0 160 175 175 200
|
||
3/0 190 210 200 225
|
||
4/0 215 240 230 260
|
||
250 250 280 255 290
|
||
350 305 340 310 350
|
||
500 380 425 385 430
|
||
750 490 545 485 540
|
||
1000 580 645 565 640
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(75) Ampacities of an Insulated Three-Conductor Copper Cable in Isolated Conduit in Air
|
||
|
||
Conductor Temperature Rating of Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 52 58 — —
|
||
6 69 77 83 92
|
||
4 91 100 105 120
|
||
2 125 135 145 165
|
||
1 140 155 165 185
|
||
1/0 165 185 195 215
|
||
2/0 190 210 220 245
|
||
3/0 220 245 250 280
|
||
4/0 255 285 290 320
|
||
250 280 315 315 350
|
||
350 350 390 385 430
|
||
500 425 475 470 525
|
||
750 525 585 570 635
|
||
1000 590 660 650 725
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(76) Ampacities of an Insulated Three-Conductor Aluminum Cable in Isolated Conduit in Air
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 41 46 — —
|
||
6 53 59 64 71
|
||
4 71 79 84 94
|
||
2 96 105 115 125
|
||
1 110 125 130 145
|
||
1/0 130 145 150 170
|
||
2/0 150 165 170 190
|
||
3/0 170 190 195 220
|
||
4/0 200 225 225 255
|
||
250 220 245 250 280
|
||
350 275 305 305 340
|
||
500 340 380 380 425
|
||
750 430 480 470 520
|
||
1000 505 560 550 615
|
||
|
||
Note: Refer to 311.60(E) for the basis of ampacities, 311.10(A) for conductor maximum operating temperature and application, and 311.60(D)(4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
##### Table 311.60(C)(77) Ampacities of Three Single-Insulated Copper Conductors in Underground Electrical Ducts (Three Conductors per Electrical Duct)
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV90105°C
|
||
(221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit \[See Figure 311.60(D)(3), Detail 1.\]
|
||
|
||
8 64 69 — —
|
||
6 85 92 90 97
|
||
4 110 120 115 125
|
||
2 145 155 155 165
|
||
1 170 180 175 185
|
||
1/0 195 210 200 215
|
||
2/0 220 235 230 245
|
||
3/0 250 270 260 275
|
||
4/0 290 310 295 315
|
||
250 320 345 325 345
|
||
350 385 415 390 415
|
||
500 470 505 465 500
|
||
750 585 630 565 610
|
||
1000 670 720 640 690
|
||
|
||
Three Circuits \[See Figure 311.60(D)(3), Detail 2.\]
|
||
|
||
8 56 60 — —
|
||
6 73 79 77 83
|
||
4 95 100 99 105
|
||
2 125 130 130 135
|
||
1 140 150 145 155
|
||
1/0 160 175 165 175
|
||
2/0 185 195 185 200
|
||
3/0 210 225 210 225
|
||
4/0 235 255 240 255
|
||
250 260 280 260 280
|
||
350 315 335 310 330
|
||
500 375 405 370 395
|
||
750 460 495 440 475
|
||
1000 525 565 495 535
|
||
|
||
Six Circuits \[See Figure 311.60(D)(3), Detail 3.\]
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV90105°C
|
||
(221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 48 52 — —
|
||
6 62 67 64 68
|
||
4 80 86 82 88
|
||
2 105 110 105 115
|
||
1 115 125 120 125
|
||
1/0 135 145 135 145
|
||
2/0 150 160 150 165
|
||
3/0 170 185 170 185
|
||
4/0 195 210 190 205
|
||
250 210 225 210 225
|
||
350 250 270 245 265
|
||
500 300 325 290 310
|
||
750 365 395 350 375
|
||
1000 410 445 390 415
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(78) Ampacities of Three Single-Insulated Aluminum Conductors in Underground Electrical Ducts (Three Conductors per Electrical Duct)
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV90105°C
|
||
(221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit \[See Figure 311.60(D)(3), Detail 1.\]
|
||
8 50 54 — —
|
||
6 66 71 70 75
|
||
4 86 93 91 98
|
||
2 115 125 120 130
|
||
1 130 140 135 145
|
||
1/0 150 160 155 165
|
||
2/0 170 185 175 190
|
||
3/0 195 210 200 215
|
||
4/0 225 245 230 245
|
||
250 250 270 250 270
|
||
350 305 325 305 330
|
||
500 370 400 370 400
|
||
750 470 505 455 490
|
||
1000 545 590 525 565
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV90105°C
|
||
(221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
Three Circuits \[See Figure 311.60(D)(3), Detail 2.\]
|
||
8 44 47 — —
|
||
6 57 61 60 65
|
||
4 74 80 77 83
|
||
2 96 105 100 105
|
||
1 110 120 110 120
|
||
1/0 125 135 125 140
|
||
2/0 145 155 145 155
|
||
3/0 160 175 165 175
|
||
4/0 185 200 185 200
|
||
250 205 220 200 220
|
||
350 245 265 245 260
|
||
500 295 320 290 315
|
||
750 370 395 355 385
|
||
1000 425 460 405 440
|
||
|
||
Six Circuits \[See Figure 311.60(D)(3), Detail 3.\]
|
||
8 38 41 — —
|
||
6 48 52 50 54
|
||
4 62 67 64 69
|
||
2 80 86 80 88
|
||
1 91 98 90 99
|
||
1/0 105 110 105 110
|
||
2/0 115 125 115 125
|
||
3/0 135 145 130 145
|
||
4/0 150 165 150 160
|
||
250 165 180 165 175
|
||
350 195 210 195 210
|
||
500 240 255 230 250
|
||
750 290 315 280 305
|
||
1000 335 360 320 345
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(79) Ampacities of Three Insulated Copper Conductors Cabled Within an Overall Covering (Three-Conductor Cable) in Underground Electrical Ducts (One Cable per Electrical Duct)
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV90105°C
|
||
(221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV90105°C
|
||
(221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit \[See Figure 311.60(D)(3), Detail 1.\]
|
||
8 59 64 — —
|
||
6 78 84 88 95
|
||
4 100 110 115 125
|
||
2 135 145 150 160
|
||
1 155 165 170 185
|
||
1/0 175 190 195 210
|
||
2/0 200 220 220 235
|
||
3/0 230 250 250 270
|
||
4/0 265 285 285 305
|
||
250 290 315 310 335
|
||
350 355 380 375 400
|
||
500 430 460 450 485
|
||
750 530 570 545 585
|
||
1000 600 645 615 660
|
||
|
||
Three Circuits \[See Figure 311.60(D)(3), Detail 2.\]
|
||
8 53 57 — —
|
||
6 69 74 75 81
|
||
4 89 96 97 105
|
||
2 115 125 125 135
|
||
1 135 145 140 155
|
||
1/0 150 165 160 175
|
||
2/0 170 185 185 195
|
||
3/0 195 210 205 220
|
||
4/0 225 240 230 250
|
||
250 245 265 255 270
|
||
350 295 315 305 325
|
||
500 355 380 360 385
|
||
750 430 465 430 465
|
||
1000 485 520 485 515
|
||
|
||
Six Circuits \[See Figure 311.60(D)(3), Detail 3.\]
|
||
8 46 50 — —
|
||
6 60 65 63 68
|
||
4 77 83 81 87
|
||
2 98 105 105 110
|
||
1 110 120 115 125
|
||
1/0 125 135 130 145
|
||
2/0 145 155 150 160
|
||
3/0 165 175 170 180
|
||
4/0 185 200 190 200
|
||
250 200 220 205 220
|
||
350 240 270 245 275
|
||
500 290 310 290 305
|
||
750 350 375 340 365
|
||
1000 390 420 380 405
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(80) Ampacities of Three Insulated Aluminum Conductors Cabled Within an Overall Covering (Three-Conductor Cable) in Underground Electrical Ducts (One Cable per Electrical Duct)
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV90105°C
|
||
(221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit \[See Figure 311.60(D)(3),
|
||
|
||
Detail 1.\]
|
||
8 46 50 — —
|
||
6 61 66 69 74
|
||
4 80 86 89 96
|
||
2 105 110 115 125
|
||
1 120 130 135 145
|
||
1/0 140 150 150 165
|
||
2/0 160 170 170 185
|
||
3/0 180 195 195 210
|
||
4/0 205 220 220 240
|
||
250 230 245 245 265
|
||
350 280 310 295 315
|
||
500 340 365 355 385
|
||
750 425 460 440 475
|
||
1000 495 535 510 545
|
||
|
||
Three Circuits \[See Figure 311.60(D)(3), Detail 2.\]
|
||
8 41 44 — —
|
||
6 54 58 59 64
|
||
4 70 75 75 81
|
||
2 90 97 100 105
|
||
1 105 110 110 120
|
||
1/0 120 125 125 135
|
||
2/0 135 145 140 155
|
||
3/0 155 165 160 175
|
||
4/0 175 185 180 195
|
||
250 190 205 200 215
|
||
350 230 250 240 255
|
||
500 280 300 285 305
|
||
750 345 375 350 375
|
||
1000 400 430 400 430
|
||
|
||
Six Circuits \[See Figure 311.60(D)(3),
|
||
|
||
Detail 3.\]
|
||
8 36 39 — —
|
||
6 46 50 49 53
|
||
4 60 65 63 68
|
||
2 77 83 80 86
|
||
1 87 94 90 98
|
||
1/0 99 105 105 110
|
||
2/0 110 120 115 125
|
||
3/0 130 140 130 140
|
||
4/0 145 155 150 160
|
||
250 160 170 160 170
|
||
350 190 205 190 205
|
||
500 230 245 230 245
|
||
750 280 305 275 295
|
||
1000 320 345 315 335
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(81) Ampacities of Single Insulated Copper Conductors Directly Buried in Earth
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit, Three Conductors \[See Figure 311.60(D)(3), Detail 9.\]
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
8 110 115 — —
|
||
6 140 150 130 140
|
||
4 180 195 170 180
|
||
2 230 250 210 225
|
||
1 260 280 240 260
|
||
1/0 295 320 275 295
|
||
2/0 335 365 310 335
|
||
3/0 385 415 355 380
|
||
4/0 435 465 405 435
|
||
250 470 510 440 475
|
||
350 570 615 535 575
|
||
500 690 745 650 700
|
||
750 845 910 805 865
|
||
1000 980 1055 930 1005
|
||
|
||
Two Circuits, Six Conductors \[See Figure 311.60(D)(3), Detail 10.\]
|
||
8 100 110 — —
|
||
6 130 140 120 130
|
||
4 165 180 160 170
|
||
2 215 230 195 210
|
||
1 240 260 225 240
|
||
1/0 275 295 255 275
|
||
2/0 310 335 290 315
|
||
3/0 355 380 330 355
|
||
4/0 400 430 375 405
|
||
250 435 470 410 440
|
||
350 520 560 495 530
|
||
500 630 680 600 645
|
||
750 775 835 740 795
|
||
1000 890 960 855 920
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(82) Ampacities of Single Insulated Aluminum Conductors Directly Buried in Earth
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit, Three Conductors \[See Figure 311.60(D)(3), Detail 9.\]
|
||
8 85 90 — —
|
||
6 110 115 100 110
|
||
4 140 150 130 140
|
||
2 180 195 165 175
|
||
1 205 220 185 200
|
||
1/0 230 250 215 230
|
||
2/0 265 285 245 260
|
||
3/0 300 320 275 295
|
||
4/0 340 365 315 340
|
||
250 370 395 345 370
|
||
350 445 480 415 450
|
||
500 540 580 510 545
|
||
750 665 720 635 680
|
||
1000 780 840 740 795
|
||
|
||
Two Circuits, Six Conductors \[See Figure 311.60(D)(3), Detail 10.\]
|
||
8 80 85 — —
|
||
6 100 110 95 100
|
||
4 130 140 125 130
|
||
2 165 180 155 165
|
||
1 190 200 175 190
|
||
1/0 215 230 200 215
|
||
2/0 245 260 225 245
|
||
3/0 275 295 255 275
|
||
4/0 310 335 290 315
|
||
250 340 365 320 345
|
||
350 410 440 385 415
|
||
500 495 530 470 505
|
||
750 610 655 580 625
|
||
1000 710 765 680 730
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(83) Ampacities of Three Insulated Copper Conductors Cabled Within an Overall Covering (Three-Conductor Cable), Directly Buried in Earth
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit \[See Figure 311.60(D)(3), Detail 5.\]
|
||
8 85 89 — —
|
||
6 105 115 115 120
|
||
4 135 150 145 155
|
||
2 180 190 185 200
|
||
1 200 215 210 225
|
||
1/0 230 245 240 255
|
||
2/0 260 280 270 290
|
||
3/0 295 320 305 330
|
||
4/0 335 360 350 375
|
||
250 365 395 380 410
|
||
350 440 475 460 495
|
||
500 530 570 550 590
|
||
750 650 700 665 720
|
||
1000 730 785 750 810
|
||
|
||
Two Circuits \[See Figure 311.60(D)(3), Detail 6.\]
|
||
8 80 84 — —
|
||
6 100 105 105 115
|
||
4 130 140 135 145
|
||
2 165 180 170 185
|
||
1 185 200 195 210
|
||
1/0 215 230 220 235
|
||
2/0 240 260 250 270
|
||
3/0 275 295 280 305
|
||
4/0 310 335 320 345
|
||
250 340 365 350 375
|
||
350 410 440 420 450
|
||
500 490 525 500 535
|
||
750 595 640 605 650
|
||
1000 665 715 675 730
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(84) Ampacities of Three Insulated Aluminum Conductors Cabled Within an Overall Covering (Three-Conductor Cable), Directly Buried in Earth
|
||
|
||
Conductor Temperature Rating of Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit \[See Figure 311.60(D)(3), Detail 5.\]
|
||
8 65 70 — —
|
||
6 80 88 90 95
|
||
4 105 115 115 125
|
||
2 140 150 145 155
|
||
1 155 170 165 175
|
||
1/0 180 190 185 200
|
||
2/0 205 220 210 225
|
||
3/0 230 250 240 260
|
||
4/0 260 280 270 295
|
||
250 285 310 300 320
|
||
350 345 375 360 390
|
||
500 420 450 435 470
|
||
750 520 560 540 580
|
||
1000 600 650 620 665
|
||
|
||
Two Circuits \[See Figure 311.60(D)(3), Detail 6.\]
|
||
8 60 66 — —
|
||
6 75 83 80 95
|
||
4 100 110 105 115
|
||
2 130 140 135 145
|
||
1 145 155 150 165
|
||
1/0 165 180 170 185
|
||
2/0 190 205 195 210
|
||
3/0 215 230 220 240
|
||
4/0 245 260 250 270
|
||
250 265 285 275 295
|
||
350 320 345 330 355
|
||
500 385 415 395 425
|
||
750 480 515 485 525
|
||
1000 550 590 560 600
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(85) Ampacities of Three Triplexed Single Insulated Copper Conductors Directly Buried in Earth
|
||
|
||
Conductor
|
||
|
||
Size
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
(AWG or kcmil) 90°C (194°F) Type MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F) Type MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
90°C (194°F) Type
|
||
|
||
MV-90
|
||
105°C (221°F) Type
|
||
|
||
MV-105
|
||
|
||
One Circuit, Three Conductors \[See Figure 311.60(D)(3), Detail 7.\]
|
||
8 90 95 — —
|
||
6 120 130 115 120
|
||
4 150 165 150 160
|
||
2 195 205 190 205
|
||
1 225 240 215 230
|
||
1/0 255 270 245 260
|
||
2/0 290 310 275 295
|
||
3/0 330 360 315 340
|
||
4/0 375 405 360 385
|
||
250 410 445 390 410
|
||
350 490 580 470 505
|
||
500 590 635 565 605
|
||
750 725 780 685 740
|
||
1000 825 885 770 830
|
||
|
||
Two Circuits, Six Conductors \[See Figure 311.60(D)(3), Detail 8.\]
|
||
8 85 90 — —
|
||
6 110 115 105 115
|
||
4 140 150 140 150
|
||
2 180 195 175 190
|
||
1 205 220 200 215
|
||
1/0 235 250 225 240
|
||
2/0 265 285 255 275
|
||
3/0 300 320 290 315
|
||
4/0 340 365 325 350
|
||
250 370 395 355 380
|
||
350 445 480 425 455
|
||
500 535 575 510 545
|
||
750 650 700 615 660
|
||
1000 740 795 690 745
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
##### Table 311.60(C)(86) Ampacities of Three Triplexed Single Insulated Aluminum Conductors Directly Buried in Earth
|
||
|
||
Conductor
|
||
|
||
Size
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
(AWG or kcmil)
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
|
||
Conductor
|
||
|
||
Size
|
||
(AWG or kcmil)
|
||
|
||
Temperature Rating of Conductor
|
||
2001–5000 Volts Ampacity 5001–35,000 Volts Ampacity
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
90°C (194°F)
|
||
|
||
Type MV-90
|
||
105°C (221°F)
|
||
|
||
Type MV-105
|
||
|
||
One Circuit, Three Conductors \[See Figure 311.60(D)(3), Detail 7.\]
|
||
8 70 75 — —
|
||
6 90 100 90 95
|
||
4 120 130 115 125
|
||
2 155 165 145 155
|
||
1 175 190 165 175
|
||
1/0 200 210 190 205
|
||
2/0 225 240 215 230
|
||
3/0 255 275 245 265
|
||
4/0 290 310 280 305
|
||
250 320 350 305 325
|
||
350 385 420 370 400
|
||
500 465 500 445 480
|
||
750 580 625 550 590
|
||
1000 670 725 635 680
|
||
|
||
Two Circuits, Six Conductors \[See Figure 311.60(D)(3), Detail 8.\]
|
||
8 65 70 — —
|
||
6 85 95 85 90
|
||
4 110 120 105 115
|
||
2 140 150 135 145
|
||
1 160 170 155 170
|
||
1/0 180 195 175 190
|
||
2/0 205 220 200 215
|
||
3/0 235 250 225 245
|
||
4/0 265 285 255 275
|
||
250 290 310 280 300
|
||
350 350 375 335 360
|
||
500 420 455 405 435
|
||
750 520 560 485 525
|
||
1000 600 645 565 605
|
||
|
||
Note: Refer to 311.60(F) for basis of ampacities and Table 311.10(A) for the temperature rating of the conductor.
|
||
|
||
#### 311.60(D) Ampacity Adjustment.
|
||
|
||
##### 311.60(D)(1) Grounded Shields.
|
||
|
||
Ampacities shown in Table 311.60(C)(69), Table 311.60(C)(70), Table 311.60(C)(81), and Table 311.60(C)(82) shall apply for cables with shields grounded at one point only. Where shields for these cables are grounded at more than one point, ampacities shall be adjusted to take into consideration the heating due to shield currents.
|
||
|
||
> [!info] Informational Note:
|
||
> Tables other than those listed contain the ampacity of cables with shields grounded at multiple points.
|
||
|
||
##### 311.60(D)(2) Burial Depth.
|
||
|
||
Where the burial depth of direct burial or electrical duct bank circuits is modified from the values shown in a figure or table, ampacities shall be permitted to be modified as indicated in 311.60(D)(2)(a) and (D)(2)(b). No ampacity adjustments shall be required where the burial depth is decreased.
|
||
|
||
* (a) Where burial depths are increased in part(s) of an electrical duct run, a decrease in ampacity of the conductors shall not be required, provided the total length of parts of the duct run increased in depth is less than 25 percent of the total run length.
|
||
|
||
* (b) Where burial depths are deeper than shown in a specific underground ampacity table or figure, an ampacity derating factor of
|
||
6 percent per 300 mm (1 ft) increase in depth for all values of rho shall be permitted.
|
||
|
||
##### 311.60(D)(3) Electrical Ducts Entering Equipment Enclosures.
|
||
|
||
At locations where electrical ducts enter equipment enclosures from underground, spacing between such ducts, as shown in Figure 311.60(D)(3), shall be permitted to be reduced without requiring the ampacity of conductors therein to be reduced.
|
||
|
||
###### Figure 311.60(D)(3) Cable Installation Dimensions for Use with Table 311.60(C)(77) Through Table 311.60(C)(86).
|
||
|
||
%% TODO %%
|
||
|
||
##### 311.60(D)(4) Ambient Temperature Correction.
|
||
|
||
Ampacities for ambient temperatures other than those specified in the ampacity tables shall be corrected in accordance with Table 311.60(D)(4) or shall be permitted to be calculated using the following equation:
|
||
|
||
###### Equation 311.60(D)(4)
|
||
|
||
$$
|
||
I^{\prime} = I \sqrt{\frac{ T_{c} -T_{a}^{\prime} }{ T_{c} - T_a }}
|
||
$$
|
||
|
||
where:
|
||
|
||
* $I\prime$ = ampacity corrected for ambient temperature
|
||
* $I$ = ampacity shown in the tables
|
||
* $T_{c}$ = temperature rating of conductor (°C)
|
||
* $T_{a}^{\prime}$ = new ambient temperature (°C)
|
||
* $T_a$ = ambient temperature used in the table (°C)
|
||
|
||
###### Table 311.60(D)(4) Ambient Temperature Correction Factors
|
||
|
||
For ambient temperatures other than 40°C (104°F), multiply the allowable ampacities specified in the ampacity tables by the appropriate factor shown below.
|
||
|
||
| Ambient Temperature °C (°F) | 90°C | 105°C |
|
||
| --------------------------- | ---- | ----- |
|
||
| 10 or less (50 or less) | 1.26 | 1.21 |
|
||
| 11–15 (51–59) | 1.22 | 1.18 |
|
||
| 16–20 (60–68) | 1.18 | 1.14 |
|
||
| 21–25 (69–77) | 1.14 | 1.11 |
|
||
| 26–30 (78–86) | 1.10 | 1.07 |
|
||
| 31–35 (87–95) | 1.05 | 1.04 |
|
||
| 36–40 (96–104) | 1.00 | 1.00 |
|
||
| 41–45 (105–113) | 0.95 | 0.96 |
|
||
| 46–50 (114–122) | 0.89 | 0.92 |
|
||
| 51–55 (123–131) | 0.84 | 0.88 |
|
||
| 56–60 (132–140) | 0.77 | 0.83 |
|
||
| 61–65 (141–149) | 0.71 | 0.78 |
|
||
| 66–70 (150–158) | 0.63 | 0.73 |
|
||
| 71–75 (159–167) | 0.55 | 0.68 |
|
||
| 76–80 (168–176) | 0.45 | 0.62 |
|
||
| 81–85 (177–185) | 0.32 | 0.55 |
|
||
| 86–90 (186–194) | — | 0.48 |
|
||
| 91–95 (195–203) | — | 0.39 |
|
||
| 96–100 (204–212) | — | 0.28 |
|
||
|
||
#### 311.60(E) Ampacity in Air.
|
||
|
||
Ampacities for conductors and cables in air shall be as specified in Table 311.60(C)(67) through Table 311.60(C)(76). Ampacities shall be based on the following:
|
||
|
||
* (1) Conductor temperatures of 90°C (194°F) and 105°C (221°F)
|
||
|
||
* (2) Ambient air temperature of 40°C (104°F)
|
||
|
||
> [!info] Informational Note:
|
||
> See 311.60(D)(4) where the ambient air temperature is other than 40°C (104°F).
|
||
|
||
#### 311.60(F) Ampacity in Underground Electrical Ducts and Direct Buried in Earth.
|
||
|
||
Ampacities for conductors and cables
|
||
in underground electrical ducts and direct buried in earth
|
||
shall be as specified in Table 311.60(C)(77) through Table 311.60(C)(86).
|
||
Ampacities shall be based on the following:
|
||
|
||
* (1) Ambient earth temperature of 20°C (68°F)
|
||
|
||
* (2) Arrangement in accordance with Figure 311.60(D)(3)
|
||
|
||
* (3) 100 percent load factor
|
||
|
||
* (4) Thermal resistance (Rho) of 90
|
||
|
||
* (5) Conductor temperatures 90°C (194°F) and 105°C (221°F)
|
||
|
||
* (6) Minimum burial depths to the top electrical ducts or cables
|
||
shall be in accordance with 300.50.
|
||
|
||
* (7) Maximum depth to the top of electrical duct banks shall be 750 mm (30 in.),
|
||
and maximum depth to the top of direct-buried cables shall be 900 mm (36 in.).
|