Electrical Feeder
The conductors that carry power from the service to the panels.
Quick Answer
An electrical feeder is the set of conductors between the service equipment or another power source and the final branch-circuit overcurrent device, typically feeding a panel, switchboard or transformer. Feeders are taken off in linear feet from the one-line diagram and riser, with conduit, conductors and terminations priced separately.
The Full Picture
The definition is about position in the system. Under the OSHA electrical definitions, a feeder is all the circuit conductors between the service equipment or other source and the final branch-circuit overcurrent device. A service brings power from the utility to the building, feeders move it to panels and equipment, and branch circuits take it from there to the outlets.
The one-line diagram is the main document for feeders. It shows each feeder as a line between equipment with a label for the number of conductors, the conductor size and the conduit, and the breaker or fuse that protects it. The riser diagram shows the vertical route of those feeders between floors and electrical rooms. Plans show the horizontal routing, and the spec sets the conductor material and wiring method. Feeder schedules often combine the sizes in one table.
The takeoff unit is the linear foot of the run, multiplied by the conductors in the feeder. A feeder with parallel sets multiplies again. Conduit, supports and pull boxes are priced against the same run. Terminations are counted EA, one set at each end, with lugs or connectors sized to the conductor. Horizontal lengths come from scale, and vertical lengths from floor-to-floor heights on the riser. Both need an allowance for offsets, bends and the extra length at each end.
Feeders are among the largest single lines on an electrical estimate, so errors weigh heavily. Typical misses are measuring the horizontal run from the wrong location of the panel, not counting the vertical rise, forgetting the neutral or ground conductor, and missing a feeder size change on a revised one-line. Long feeders may also need pull boxes, and fire-rated shaft penetrations need sleeves and firestopping.
Real Examples
Common Misconceptions
People assume: A feeder is any large wire in the building.
Actually: A feeder is defined by position: it runs between the source and the final branch-circuit breaker. Big conductors on the load side of that breaker are branch wiring.
People assume: Feeder length is simply the scaled length on the plan.
Actually: Plan scale gives the horizontal run only. The vertical rise comes from the riser diagram and floor heights, and offsets and end allowances come on top.
Does MeltPlan Solve This?
Partially — adjacentFeeder routes and lengths are measured from the plans, one-line diagram and riser, and MeltPlan's takeoff service covers that measuring: AI pulls quantities from the plans, and US-based experienced estimators review and adjust them. Conductor sizing and the routing judgment stay with your estimator.
Get feeder lengths measured from your electrical plans →Frequently Asked Questions
What is an electrical feeder?
A feeder is the set of conductors that carries power from the service equipment or another source to the last overcurrent device in a branch-circuit panel. It usually feeds panels, switchboards and transformers.
Where do I find feeders on the drawings?
The one-line diagram lists each feeder with its conductors, size and protection. The riser diagram shows the vertical route and the plans show the horizontal routing.
How is a feeder measured in a takeoff?
It is measured in linear feet of run, then multiplied by the number of conductors and by parallel sets. Terminations are counted EA at each end.
What is the difference between a feeder and a service?
A service delivers energy from the utility to the building's wiring system. Feeders start at the service equipment and distribute power onward to panels.