VII. Service Equipment — Overcurrent Protection

230.90 Where Required.

Quote
230.90(A)(1)Exception No. 3: Two to six circuit breakers or sets of fuses shall be permitted as the overcurrent device to provide the overload protection. The sum of the ratings of the circuit breakers or fuses shall be permitted to exceed the ampacity of the service conductors, provided the calculated load does not exceed the ampacity of the service conductors.


Can someone explain the wisdom of this?

If this is applied you are leaving it up to the next person to do load calculations for each and every addition to the service.

For all we talk about taps and proper OCP this seems to go against the general requirements.

Bob

Bob Badger
Construction & Maintenance Electrician
Massachusetts