Testing & TroubleshootingQuestion 509 of 521
A branch-circuit breaker trips instantly every time it is reset, with nothing plugged in. Continuity from hot to ground reads near 0 ohms. What is the most likely fault?
a.Simple overload from too many appliances
b.An open neutral
c.A short circuit (hot-to-ground or hot-to-neutral) in the wiring
d.Undersized service transformer
Explanation
Instant tripping with no load, plus a near-0 ohm hot-to-ground reading, points to a bolted short circuit providing a very low-resistance fault path. An overload (a) needs connected load and trips on a time delay, an open neutral (b) would not trip the breaker, and transformer sizing (d) does not cause instantaneous branch trips.
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