---
id: feeders
aliases: []
tags:
  - occupational/systems/feeders
  - type/guide
---
# Feeders

## Info

### Routing and Structural Considerations

#### Shear Walls

Shear walls, like those around stairwells and elevator shafts,
may be routed through with special permission.

#### Post-Tensioned Slabs

> [!example]
> STRUCTURAL SLAB IS AN 8-INCH THICK
> UNBONDED POST-TENSIONED TWO-WAY SLAB UNLESS NOTED OTHERWISE.

> [!cite] Joel Jansen 2025-08-15, in reference to Belle Meade Plaza (pp.)
> No affect on takeoff. Routing in slab still possible.

> [!cite] Joel Jansen 2025-08-21, in reference to Belle Meade Plaza (pp.)
> PT slabs do have some affect on takeoff.
> 3in conduit can not be run in an 11in PT slab.

#### Pan Deck Slabs

> [!example]
> STRUCTURAL SLAB IS 3 1/2 INCHES OF NORMALWEIGHT CONCRETE
> ON 3-INCH COMPOSITE STEEL DECK UNLESS NOTED OTHERWISE.

> [!cite] Joel Jansen 2025-08-15, in reference to Belle Meade Plaza (pp.)
> Do not route in slab.

#### Fire Rated Feeders

PDI estimating practice is to run all "emergency" feeds
(life-safety or just standby)
in a 2-hour rated assembly.
This usually requires no change to takeoff for high-rises
since electrical riser rooms are themselves fire-rated.

* RHW-2 insulated conductors in conduit -- "Lifeline Cable"
* 2-hour rated metal clad cable -- "Vitalink"

### Formatting

All feeder takeoff descriptions should be prefixed with `<parent> TO <child>`

> [!cite] Joel Jansen, in reference to Omni Hotels Raleigh, pp.
> It is acceptable to use typicals for identical feeders
> (i.e. meter centers fed from bus plugs)
> so long as the typical is in the Feeders `Area`.

## Sequence

### 1. Preparation

Read about the project specifications and construction type:
* Deck thickness
* Wiring methods
* Conductor material
* Wire terminations (set-screw acceptable or compression required?)

Locate:
* Riser Diagram
* Feeder Schedule (if present)
* Main Electrical rooms and panel locations

### 2. Takeoff

Run parallel to building lines
and route through corridors where possible.

> [!important]
> All takeoffs in Systems with names including "site"
> should be in "Site" Area, Phase, and Bid Item breakdowns.

For adjacent panels, use a minimum 10ft length.

#### Adders

Use the difference in elevation between equipment
or 10ft, whichever is greater.

Add an additional 5ft (total 15ft) for site runs
(primaries, secondaries, etc.).

#### Primaries

Usually only empty conduit if included.

#### Secondaries

##### Wiring on Vault Racks

Where secondary conductors run on racks in utility vaults
manually set the length of conduit,
measure the wire length,
add 20ft in addition to previously mentioned adders.

#### Feeders

`Area` = "01 - Feeders/Risers Building"
for all feeders, no matter the location.

#### Bus Duct

`COMMON ASSEMBLIES`/`DISTRIBUTION`/`BUS DUCT`

#### Cable Support

> [!quote] 300.19 Supporting Conductors in Vertical Raceways.
> **(A) Spacing Intervals -- Maximum.**
> Conductors in vertical raceways shall be supported
> if the vertical rise exceeds the values in Table 300.19(A).
> At least one support method shall be provided for each conductor
> at the top of the vertical raceway or as close to the top as practical.
> Intermediate supports shall be provided
> as necessary to limit supported conductor lengths
> to not greater than those values specified in Table 300.19(A).

> [!cite] Table 300.19(A) Spacings for Conductor Supports
>
> | Conductor Size                   | Aluminum or Copper-Clad Aluminum | Copper |
> | -------------------------------- | --------------------------------:| ------:|
> | 18 AWG through 8 AWG             |                            100ft |  100ft |
> | 6 AWG through 1/0 AWG            |                            200ft |  100ft |
> | 2/0 AWG through 4/0 AWG          |                            180ft |   80ft |
> | Over 4/0 AWG through 350 kcmil   |                            135ft |   60ft |
> | Over 350 kcmil through 500 kcmil |                            120ft |   50ft |
> | Over 500 kcmil through 750 kcmil |                             95ft |   40ft |
> | Over 750 kcmil                   |                             85ft |   35ft |

`ITEM DATABASE`/`CONDUIT & FITTINGS`/`CABLE SUPPORT / WEDGES`/`... COMPLETE FITTING`/...

#### Grounding

See [[grounding]].

#### Sleeving

See [[sleeving]].

### 3. Review
