/ Field knowledge · NEC 100 · Sparky Edition
Not every conductor leaving a panel is a feeder.
NEC Article 100: not every conductor leaving a panel is a feeder. The final branch-circuit overcurrent protective device is the boundary.
Educational 2026 NEC Article 100 terminology. Confirm the adopted edition. This is not a conductor size or voltage-drop calculation. Distinct from service vs feeder.
- A feeder consists of conductors between the service equipment, separately derived system source, or other power-supply source and the final branch-circuit overcurrent protective device.
- A branch circuit consists of conductors between the final overcurrent protective device protecting the circuit and the outlet(s).
- An OCPD (breaker or fuse) opens a circuit when current exceeds permitted limits.
In a path such as service → switchboard → panelboard → RTU disconnect → RTU, the final branch-circuit OCPD — not a casual label — establishes the boundary. That affects conductor and OCPD selection, panel schedules, load calculations, voltage-drop, grounding/bonding, and reuse of existing circuits.
“This is a feeder”
Ask two follow-ups: what is the final branch-circuit OCPD, and what outlet/load does it serve? Do not classify an existing circuit from an assumed route alone. For an existing building, test rather than infer circuit origin when that fact controls scope or safety — using qualified personnel and required safe-work procedures.
Source: Sparky branch/feeder · tool: OCPD screen · service: service boundaries.
What to send
The one-line and which load the renovation team is calling a “feeder.”
If the renovation team called it a feeder
Send the one-line. Masterbuild will say where the final OCPD actually sits — or the label was a guess.
Send Project Background+1 (786) 398-6940 · osmany.portal@masterbuildconsulting.com
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