NCCER Load Calculations – Feeders and Services (26401-23) Practice Test

Taps that supply a transformer have a special allowance in the NEC. This rule lets you run a short length of conductors from the feeder to a transformer, and you count both the primary and the transformer’s secondary conductors as part of those taps, with a total length not exceeding 25 feet. Keeping this arrangement as a short tap ensures proper protection coordination and limits voltage drop, without turning the connection into a full feeder run.

That’s why this option is the best fit: it mirrors the exact scenario described in the code—a transformer fed by a short tap (primary plus secondary) limited to 25 feet. The other choices don’t match this specific provision: outside taps aren’t unlimited in length; feeder taps fall under a different rule; and transformer secondary conductors are part of the transformer circuit, not a separate tap supply under this section.