| Medium voltage solid dielectric | MV-90<br>MV-105* | 90°C<br>105°C | Dry or wet locations | Thermoplastic or thermosetting | Jacket, sheath, or armor |
| Trade Name | Type Letter | Maximum Operating Temperature | Application Provision | Insulation | Outer Covering |
| Medium voltage solid dielectric | MV-90 | 90°C | Dry or wet locations | Thermoplastic or thermosetting | Jacket, sheath, or armor |
| | MV-105<sup>\*</sup> | 105°C | | | |
\*Where design conditions require maximum conductor temperatures above 90°C.
<sup>\*</sup>Where design conditions require maximum conductor temperatures above 90°C.
#### 311.10(B) Thickness of Insulation and Jacket for Nonshielded Insulated Conductors.
Thickness of insulation and jacket for nonshielded solid dielectric insulated conductors rated 2001 volts to 5000 volts shall comply with Table 311.10(B).
Thickness of insulation and jacket for nonshielded solid dielectric insulated conductors rated 2001 volts to 5000 volts
shall comply with Table 311.10(B).
##### Table 311.10(B) Thickness of Insulation and Jacket for Nonshielded Solid Dielectric Insulated Conductors
##### Table 311.10(B) Thickness of Insulation and Jacket for Nonshielded Solid Dielectric Insulated Conductors Rated 2001 Volts to 5000 Volts
Rated 2001 Volts to 5000 Volts
Overall Insulation Jacket
Dry Locations Single Conductor Without Jacket 8 2.79mm (110mils)
Dry Locations Single Conductor Without Jacket 6 2.79mm (110mils)
Dry Locations Single Conductor Without Jacket 4–2 2.79mm (110mils)
Dry Locations Single Conductor Without Jacket 1–2/0 2.79mm (110mils)
Dry Locations Single Conductor Without Jacket 3/0–4/0 2.79mm (110mils)
Dry Locations Single Conductor Without Jacket 213–500 3.05mm (120mils)
Dry Locations Single Conductor Without Jacket 501–750 3.30mm (130mils)
Dry Locations Single Conductor Without Jacket 751–1000 3.30mm (130mils)
Dry Locations Single Conductor Without Jacket 1001–1250 3.56mm (140mils)
Dry Locations Single Conductor Without Jacket 1251–1500 3.56mm (140mils)
Dry Locations Single Conductor Without Jacket 1501–2000 3.56mm (140mils)
Dry Locations Single Conductor 8 2.29mm (90mils) 0.76mm (30mils)
Dry Locations Single Conductor 6 2.29mm (90mils) 0.76mm (30mils)
Dry Locations Single Conductor 4–2 2.29mm (90mils) 1.14mm (45mils)
Dry Locations Single Conductor 1–2/0 2.29mm (90mils) 1.14mm (45mils)
Dry Locations Single Conductor 3/0–4/0 2.29mm (90mils) 1.65mm (65mils)
Dry Locations Single Conductor 213–500 2.29mm (90mils) 1.65mm (65mils)
Dry Locations Single Conductor 501–750 2.29mm (90mils) 1.65mm (65mils)
Dry Locations Single Conductor 751–1000 2.29mm (90mils) 1.65mm (65mils)
Dry Locations Single Conductor 1001–1250 2.92mm (115mils) 1.65mm (65mils)
Dry Locations Single Conductor 1251–1500 2.92mm (115mils) 2.03mm (80mils)
Dry Locations Single Conductor 1501–2000 2.92mm (115mils) 2.03mm (80mils)
Wet or Dry Locations Single Conductor 8 3.18mm (125mils) 2.03mm (80mils)
Wet or Dry Locations Single Conductor 6 3.18mm (125mils) 2.03mm (80mils)
Wet or Dry Locations Single Conductor 4–2 3.18mm (125mils) 2.03mm (80mils)
Wet or Dry Locations Single Conductor 1–2/0 3.18mm (125mils) 2.03mm (80mils)
Wet or Dry Locations Single Conductor 3/0–4/0 3.18mm (125mils) 2.41mm (95mils)
Wet or Dry Locations Single Conductor 213–500 3.56mm (140mils) 2.79mm (110mils)
Wet or Dry Locations Single Conductor 501–750 3.94mm (155mils) 3.18mm (125mils)
Wet or Dry Locations Single Conductor 751–1000 3.94mm (155mils) 3.18mm (125mils)
Wet or Dry Locations Single Conductor 1001–1250 4.32mm (170mils) 3.56mm (140mils)
Wet or Dry Locations Single Conductor 1251–1500 4.32mm (170mils) 3.56mm (140mils)
Wet or Dry Locations Single Conductor 1501–2000 4.32mm (170mils) 3.94mm (155mils)
Wet or Dry Locations Multiconductor Insulation* 8 2.29mm (90mils)
Wet or Dry Locations Multiconductor Insulation* 6 2.29mm (90mils)
Wet or Dry Locations Multiconductor Insulation* 4–2 2.29mm (90mils)
Wet or Dry Locations Multiconductor Insulation* 1–2/0 2.29mm (90mils)
Wet or Dry Locations Multiconductor Insulation* 3/0–4/0 2.29mm (90mils)
Wet or Dry Locations Multiconductor Insulation* 213–500 2.29mm (90mils)
Wet or Dry Locations Multiconductor Insulation* 501–750 2.29mm (90mils)
Wet or Dry Locations Multiconductor Insulation* 751–1000 2.29mm (90mils)
Wet or Dry Locations Multiconductor Insulation* 1001–1250 2.92mm (115mils)
Wet or Dry Locations Multiconductor Insulation* 1251–1500 2.92mm (115mils)
Wet or Dry Locations Multiconductor Insulation* 1501–2000 3.56mm (140mils)
Conductor
Size
(AWG or kcmil)
Dry Locations, Single Conductor Wet or Dry Locations
Without Jacket
Insulation
With Jacket Single Conductor Multiconductor
Insulation*
Insulation Jacket Insulation Jacket mm mils mm mils mm mils mm mils mm mils mm mils
*Under a common overall covering such as a jacket, sheath, or armor.
Conductor
Size
(AWG or kcmil)
Conductor Size (AWG or kcmil)
25,001–28,000 Volts 28,001–35,000 Volts
100
Percent
Insulation
Level
133
Percent
Insulation
Level
173
Percent
Insulation
Level
100
Percent
Insulation
Level
133
Percent
Insulation
Level
173
Percent
Insulation
100 Percent Insulation Level
133 Percent Insulation Level
173 Percent Insulation Level
100 Percent Insulation Level
133 Percent Insulation Level
173 Percent Insulation
Level mm mils mm mils mm mils mm mils mm mils mm mils
1 7.11 280 8.76 345 11.30 445 — — — — — —
@@ -169,11 +136,22 @@ Thickness of insulation for shielded solid dielectric insulated conductors rated
##### 311.10(C)(1) 100 Percent Insulation Level.
Cables shall be permitted to be applied where the system is provided with relay protection such that ground faults will be cleared as rapidly as possible but, in any case, within 1 minute. These cables are applicable to cable installations that are on grounded systems and shall be permitted to be used on other systems provided the above clearing requirements are met in completely de-energizing the faulted section.
Cables shall be permitted to be applied
where the system is provided with relay protection
such that ground faults will be cleared as rapidly as possible but, in any case, within 1 minute.
These cables are applicable to cable installations that are on grounded systems
and shall be permitted to be used on other systems
provided the above clearing requirements are met
in completely de-energizing the faulted section.
##### 311.10(C)(2) 133 Percent Insulation Level.
Cables shall be permitted to be applied in situations where the clearing time requirements of the 100 percent level category cannot be met and the faulted section will be de-energized in a time not exceeding 1 hour. Cable shall be permitted to be used in 100 percent insulation level applications where the installation requires additional insulation.
Cables shall be permitted to be applied
in situations where the clearing time requirements
of the 100 percent level category cannot be met
and the faulted section will be de-energized in a time not exceeding 1 hour.
Cable shall be permitted to be used in 100 percent insulation level applications
where the installation requires additional insulation.
##### 311.10(C)(3) 173 Percent Insulation Level.
@@ -310,8 +288,7 @@ One or more of the methods in 311.16(B)(1) through (B)(4) shall be used for mark
##### 311.16(B)(1) Surface Marking.
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.).
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.).
##### 311.16(B)(2) Marker Tape.
@@ -450,24 +427,21 @@ Under engineering supervision, conductor ampacities shall be permitted to be cal
conductor temperature (°C) ambient temperature (°C) dielectric loss temperature rise dc resistance of conductor at temperature, T component ac resistance resulting from skin effect and proximity effect effective thermal resistance between conductor and surrounding ambient c a d dc c c ca
* $T_{c}$ 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 (ΔT ) is negligible for single circuit extruded dielectric cables rated below 46 kilovolts.
> The dielectric loss temperature rise ($\Delta T_{d}$)
> is negligible for single circuit extruded dielectric cables rated below 46 kilovolts.
#### 311.60(C) Tables.
@@ -518,8 +492,7 @@ MV-105
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).
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
@@ -577,8 +550,7 @@ MV-105
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).
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
@@ -629,8 +601,7 @@ Type MV-105
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).
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
@@ -739,8 +710,7 @@ MV-105
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).
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
@@ -778,8 +748,7 @@ MV-105
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).
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
@@ -837,8 +806,7 @@ MV-105
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).
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
@@ -873,8 +841,7 @@ MV-105
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).
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
@@ -930,8 +897,7 @@ MV-105
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).
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
@@ -991,9 +957,8 @@ MV-90
MV-105
One Circuit \[See Figure 311.60(D)(3),
One Circuit \[See Figure 311.60(D)(3), Detail 1.\]
Detail 1.\]
8 64 69 — —
6 85 92 90 97
4 110 120 115 125
@@ -1009,9 +974,8 @@ Detail 1.\]
750 585 630 565 610
1000 670 720 640 690
Three Circuits \[See Figure 311.60(D)(3),
Three Circuits \[See Figure 311.60(D)(3), Detail 2.\]
Detail 2.\]
8 56 60 — —
6 73 79 77 83
4 95 100 99 105
@@ -1027,9 +991,7 @@ Detail 2.\]
750 460 495 440 475
1000 525 565 495 535
Six Circuits \[See Figure 311.60(D)(3),
Detail 3.\]
Six Circuits \[See Figure 311.60(D)(3), Detail 3.\]
Conductor
@@ -1085,9 +1047,7 @@ MV-90
MV-105
One Circuit \[See Figure 311.60(D)(3),
Detail 1.\]
One Circuit \[See Figure 311.60(D)(3), Detail 1.\]
8 50 54 — —
6 66 71 70 75
4 86 93 91 98
@@ -1121,9 +1081,7 @@ MV-90
MV-105
Three Circuits \[See Figure 311.60(D)(3),
Detail 2.\]
Three Circuits \[See Figure 311.60(D)(3), Detail 2.\]
8 44 47 — —
6 57 61 60 65
4 74 80 77 83
@@ -1139,9 +1097,7 @@ Detail 2.\]
750 370 395 355 385
1000 425 460 405 440
Six Circuits \[See Figure 311.60(D)(3),
Detail 3.\]
Six Circuits \[See Figure 311.60(D)(3), Detail 3.\]
8 38 41 — —
6 48 52 50 54
4 62 67 64 69
@@ -1197,9 +1153,7 @@ MV-90
MV-105
One Circuit \[See Figure 311.60(D)(3),
Detail 1.\]
One Circuit \[See Figure 311.60(D)(3), Detail 1.\]
8 59 64 — —
6 78 84 88 95
4 100 110 115 125
@@ -1215,9 +1169,7 @@ Detail 1.\]
750 530 570 545 585
1000 600 645 615 660
Three Circuits \[See Figure 311.60(D)(3),
Detail 2.\]
Three Circuits \[See Figure 311.60(D)(3), Detail 2.\]
8 53 57 — —
6 69 74 75 81
4 89 96 97 105
@@ -1233,31 +1185,11 @@ Detail 2.\]
750 430 465 430 465
1000 485 520 485 515
Six Circuits \[See Figure 311.60(D)(3),
Detail 3.\]
Six Circuits \[See Figure 311.60(D)(3), Detail 3.\]
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.
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).
##### 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)
###### Figure 311.60(D)(3) Cable Installation Dimensions for Use with Table 311.60(C)(77) Through Table 311.60(C)(86).
%% TODO %%
I' =
##### 311.60(D)(4) Ambient Temperature Correction.
I =
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:
T = where: ampacity corrected for ambient temperature ampacity shown in the table for T and T temperature rating of conductor (°C) new ambient temperature (°C) ambient temperature used in the table (°C)
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)
Temperature Rating of Conductor Ambient
Temperature
(°F)
90°C 105°C
10 or less 1.26 1.21 50 or less
11–15 1.22 1.18 51–59
16–20 1.18 1.14 60–68
21–25 1.14 1.11 69–77
26–30 1.10 1.07 78–86
31–35 1.05 1.04 87–95
36–40 1.00 1.00 96–104
41–45 0.95 0.96 105–113
46–50 0.89 0.92 114–122
51–55 0.84 0.88 123–131
56–60 0.77 0.83 132–140
61–65 0.71 0.78 141–149
66–70 0.63 0.73 150–158
71–75 0.55 0.68 159–167
76–80 0.45 0.62 168–176
81–85 0.32 0.55 177–185
86–90 — 0.48 186–194
91–95 — 0.39 195–203
96–100 — 0.28 204–212 c a c a a
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.).
| 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.
@@ -1930,3 +1801,23 @@ Ampacities for conductors and cables in air shall be as specified in Table 311.6
#### 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.).
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