147 lines
4.0 KiB
Markdown
147 lines
4.0 KiB
Markdown
---
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id:
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aliases: []
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tags:
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- destiny/permanent
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- occupational
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- status/incomplete
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- type/guide
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- authorship/original
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title: Wiring Method Selection
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---
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# Wiring Method Selection
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Determine where each wiring method can be used.
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NM/SER < PVC < MC < EMT-SS < EMT-Comp < IMC
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Below is an example Wiring Method Selection
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for a [[ibc-construction-types#5-Over-1 Construction|podium]] construction.
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> [!example]
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> Wire Material:
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> * Less than 100A: CU
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> * 100A and larger: AL
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>
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> Outdoors:
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> * Above-ground: EMT-Comp
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> * Underground: PVC w/ Rigid Elbows
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>
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> Levels 1-2 (Type IA):
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> * Concealed: MC
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> * Exposed to Structure:
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> * Up to 2"C: PVC In-Slab
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> * 2-1/2"C and larger: EMT-SS OH
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>
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> Levels 3-5 (Type IIIA):
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> * Concealed: NM/SER
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> * Exposed to Structure: PVC OH
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<!--
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This needs reworking.
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I know PVC is preferable to MC in the case of feeders, subfeeds, and possibly home runs,
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but I think they swap for branch.
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-->
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## Slab Thickness
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Conduits may not be routed through slabs of thickness
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less than 3 times the outer diameter of the conduit.
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| Conduit Size | Minimum Slab Thickness (in) |
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| ------------:| ---------------------------:|
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| 1/2" | 3.0 |
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| 3/4" | 3.5 |
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| 1" | 4.0 |
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| 1-1/4" | 5.0 |
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| 1-1/2" | 6.0 |
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| 2" | 7.5 |
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| 3" | 9.0 |
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| 2-1/2" | 10.5 |
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| 3-1/2" | 12.0 |
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| 4" | 13.5 |
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| 5" | 17.0 |
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| 6" | 20.0 |
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## By Finish
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Cable type raceways (MC, NM, SE)
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may only be used where they will be concealed from view.
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Exception:
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Temporary provisions for unfinished spaces (e.g. core and shell retail)
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## By Construction Type
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Nonmetallic-sheathed cables (NM/SER)
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are not permissible in Non-Combustible (Type I, II) constructions.
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See [[ibc-construction-types]] for more info.
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## By Use-Case
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### Multi-Circuit Homeruns
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> [!quote] Art Baldwin (pp.)
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> Multi-circuit MC is not cost-effective
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> when considering the difficulty of rework.
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> Use conduit, even EMT if necessary.
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* Market Type = Assisted Living: MC-AP may be required.
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## By Specification
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> [!info] Example Specs Relevant to Wiring Methods Selection
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> * 26XXXX - Raceway And Boxes For Electrical Systems
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> * 26XXXX - Conduits For Electrical Systems
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> * 26XXXX - Underground Ducts And Raceways For Electrical Systems
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>
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> * 26XXXX - Low-Voltage Electrical Power Conductors And Cables
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>
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> * 26XXXX - General Requirements For Electrical
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> * 26XXXX - Common Work Results For Electrical
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### Electrical Metallic Tubing (EMT)
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Set-screw fittings may not be acceptable.
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> [!info]
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> EMT has a third coupling type "indenter",
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> which are crimped onto the conduit using a special tool.
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> These are usually only mentioned in specifications
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> to say that they are unacceptable.
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> [!info] Edge Case: Vanderbilt Central Neighborhood Residential College
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>
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> > [!cite] Vanderbilt Central Neighborhood Residential College - Project Specifications (pp.)
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> > Fittings for Type EMT Duct Raceways:
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> > * Coupling Method: Compression coupling or Setscrew coupling.
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> > Setscrew couplings with only single screw per conduit are unacceptable.
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>
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> > [!quote] Joel Jansen via Microsoft Teams @ 2025-10-15 09:33 AM
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> > use set screw 🙂
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### Rigid Polyvinyl Chloride Conduit (PVC)
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Not usually permissible exposed indoors in any construction,
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except in Florida.
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May require rigid stub-ups in certain cases,
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which could make EMT more cost-effective.
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Consult with the Senior Construction Estimator in this case.
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## Flow Chart
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```mermaid
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flowchart LR
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A[Construction Type]
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A -- I, II --> B[Can can be run in slab?]
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B -- No --> D[Concealed?]
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B -- Yes --> PVC
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D -- No --> EMT
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D -- Yes --> MC
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A -- III, IV, V --> C[Concealed?]
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C -- No --> PVC
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C -- Yes --> NM/SER
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``` |