Replacement breaker help. 1 March at 7:41PM edited 1 March at 9:09PM in In my home (includes DIY) MoneySaving 14 replies 458 views

dil1976

Ectophile said:

ThisIsWeird said:

H143, are you trying to up-rate the MCB, or swap a 20 for a 20? If the former, can we ask why? Are you sure it's a good idea?

The one shown should be a direct replacement. I understand the 'B' before the rating number indicates a 'type' - how fast it responds, like the slow & fast-blow fuses you can get. Not sure which way.

The "B" is the speed rating.  You won't see "A" breakers, so "B" is the fastest.  Slower ones are "C" or "D".

In this country, we usually use "B" ones unless there's a good reason to use a slower one.

It is nothing to do with the "speed" its all to with the fault current curve which is to complicated to explain, but needless to say a B can take longer than a C to trip depending on fault currents.. There also no standard ones as different types are used in different scenarios.

WhiskersTheWonderCat

chris_n said:

You can't just assume you can change a 6A MCB for a 20A, the wiring and fittings may not be rated for 20A. MEM circuit breakers are readily available from many places.

This!

It is very unwise to simply swap a 6A MCB for a 20A. You could be creating a fire hazard. I'm also sure that it's illegal to work on a consumer unit if you aren't a certified professional.

dil1976

WhiskersTheWonderCat said:

chris_n said:

You can't just assume you can change a 6A MCB for a 20A, the wiring and fittings may not be rated for 20A. MEM circuit breakers are readily available from many places.

This!

It is very unwise to simply swap a 6A MCB for a 20A. You could be creating a fire hazard. I'm also sure that it's illegal to work on a consumer unit if you aren't a certified professional.

Its not illegal to carry out any work on a electrical installation in the UK regardless of your back ground, however should something go wrong you would need to be able to prove your competence in a court should you end up there, ignorance isn't a defence

Mutton_Geoff

There is no suggestion the OP wants to change a 6A to 20A, perhaps the 20A one is out of shot in the photo?