85 lines
2.4 KiB
Markdown
85 lines
2.4 KiB
Markdown
---
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id:
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aliases: []
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tags:
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- occupational/systems/subfeeds
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---
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# Subfeeds
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## Sequence
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### 1. Estimate preparation
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1. Read about the project specifications and construction type
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* Delivery Method: (Plans & Specs, Design Build, Design Assist, Preliminary Budget)
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* Deck Thickness
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* Corridor Ceiling type
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2. In the drawings, locate:
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* Unit Panel Schedules
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* Unit Load Calculations
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* Riser Diagram
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* Subfeed schedule (if present)
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### 2. Takeoff
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1. Determine wiring method
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| Construction Type | Wiring Method | Subfeed Options |
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| ----------------- | ------------- | --------------- |
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| 1,2 | MC Cable | MC, PVC, EMT |
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| 3,4,5 | NM Cable | SER, EMT |
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%%
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TODO: Create flow chart for wiring methods.
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Some cases to mention:
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* Deck thickness (minimum 3x conduit outer diameter)
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* Renovations (may not be able to run in slab)
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%%
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2. Route subfeeds to the Meter Centers using appropriate adder lengths
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Add an additional 10ft for makeup when using MC cable.
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> [!tip]
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> Identify if and where typicals can be used
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3. Assign material to lengths and apply Voltage drop if applicable
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4. Pigtail Adaptors and Wireway Troughs if applicable
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#### Pigtail Adaptors
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![[burndy_AYP300.png]]
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Pigtail adaptors are used where feeder wires exceed the range of panel lugs.
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| Load Center Size | Max Feeder Size |
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| ---------------- | --------------- |
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| 100A | 2/0 AWG |
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| 125A | 3/0 AWG |
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| 150A | 4/0 AWG |
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| 225A | 300 kcmil |
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| 400A | 500 kcmil |
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`ITEM DATABASE`/`WIRE & CABLE ACCESSORIES`/`WIRE LUGS & SPLICING`/`PIGTAIL ADAPTORS...`/`ADAPTOR STRAIGHT PIGTAIL - ...`
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> [!info]
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> "Pigtail adaptor" is the most common name and spelling for the device,
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> however it's something of a misnomer, having nothing to do with pigtails
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> (a short length of wire),
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> the name likely stemming from the device being used in lieu of a pigtail.
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#### Meter Center Troughs
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Only for PVC subfeeds where we own voltage drop.
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- `Area` = "Typical - Building Levels With Meter Centers"
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- `System` = "Electrical"
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- `Phase` = "Sub Feeders"
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`ITEM DATABASE`/`DISTRIBUTION`/`BUDGET ITEMS $ & LBR`/`METER CENTER WIRE TROUGH ($400/E)`
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### 3. Extension (Review and Checking)
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1. Use the extension tab to determine the Correct Quantity
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