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circuit-breaker allegedly "getting more sensitive"

Former Community Member over 4 years ago

OK, usual caravan park issues with more pitches than incoming supply, so client has acknowledged this by installing 10 A circuit-breakers for each 16 A outlet. With 24 pitches on a presumed 80 A single-phase cut-out, he has got away with it..... so far, but he doesn't close for winter....

He has a few regulars that complain about the 10 A circuit-breaker being too sensitive so client believes them and has fitted new 10 A circuit-breakers ready for this weekend.

Considering that a 10 A circuit-breaker will run at 11.3 A continuously and 16 A for about 10 minutes, I'm more inclined to think that the "shed puller's" use of the 2 kW built in heater, 2 kW supplementary fan heater, fridge and domestic 3 kW kettle plus entertainment equipment are more likely....

But, has anyone carried out any tests on circuit-breakers to prove/disprove the alleged reduced rating? Or links to any such reports?

Regards

BOD

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0 Alcomax over 4 years ago

I was under the impression Alcomax that the thermal element of the circuit-breaker (CB) was the same irrespective of it being B, C or D and only the magnetic in-rush was different. The replacement of the CB with a C or D wouldn't alter the time of an overcurrent caused by too many heaters/kettles etc but would only help if say a tool transformer or welder were connected by not responding to the high inrush current.

Yes Bod, but the anecdotal consideration was for instantaneous operation, not time for an overload, as, in practice, the [bodge] remedy does result in less claims of the MCB being "too sensitive" for campsites. Not very BS7671, but the wiring and points are already in and the customers want the electric to stay on more often than not. It is not just the number of potential loads that may "overload", it is overload of a very short duration when everything is on demand at the same time. So 30 amps instantaneous, a C type is more likely to stay in than a B type. Your client has "10 amp " points, that is fairly typical of an owner using the CB as a means of limiting how much electric a pitch is using for the usual fixed nightly sum, so there is a trade off.
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0 Alcomax over 4 years ago

I was under the impression Alcomax that the thermal element of the circuit-breaker (CB) was the same irrespective of it being B, C or D and only the magnetic in-rush was different. The replacement of the CB with a C or D wouldn't alter the time of an overcurrent caused by too many heaters/kettles etc but would only help if say a tool transformer or welder were connected by not responding to the high inrush current.

Yes Bod, but the anecdotal consideration was for instantaneous operation, not time for an overload, as, in practice, the [bodge] remedy does result in less claims of the MCB being "too sensitive" for campsites. Not very BS7671, but the wiring and points are already in and the customers want the electric to stay on more often than not. It is not just the number of potential loads that may "overload", it is overload of a very short duration when everything is on demand at the same time. So 30 amps instantaneous, a C type is more likely to stay in than a B type. Your client has "10 amp " points, that is fairly typical of an owner using the CB as a means of limiting how much electric a pitch is using for the usual fixed nightly sum, so there is a trade off.
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circuit-breaker allegedly "getting more sensitive"

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