16amp circuit

[adwt2004]

I have a spare 16amp circuit that used to be used for an immersion heater but I've removed the tank now, what i'd like to know is, could I go off this with a fused one of these

rated at 3 amps for a combi boiler? Or do I need to change the mcb?

 

[dingbat]

That's fine. The MCB is there to protect the cable.

 

[adwt2004]

Cool, thanks for the info!

 

[sparkyspike]

Is that not a 13A rated FCU? I'm prepared to be proven wrong, but should it not also be protected by a suitable MCB, i.e. a 10A?

 

[davelx]

Is a 13A FCU on a ring final protected by a 10A MCB?

 

[dingbat]

Is that not a 13A rated FCU? I'm prepared to be proven wrong, but should it not also be protected by a suitable MCB, i.e. a 10A?

No. The fuse in the FCU limits the load that can be applied downstream of it and hence the current that passes through it.

Also, wouldn't it be fun trying to run a 13A load on a 10A MCB?

 

[adwt2004]

Is that not a 13A rated FCU? I'm prepared to be proven wrong, but should it not also be protected by a suitable MCB, i.e. a 10A?

No. The fuse in the FCU limits the load that can be applied downstream of it and hence the current that passes through it.

Also, wouldn't it be fun trying to run a 13A load on a 10A MCB?

But these fuses are changeable and I was planning on putting in a 3amp one. Is that not a good idea?

 

[davelx]

That's fine

 

[securespark]

Let's be really pedantic & say that if you can fit a 3A breaker, you only need a DP switch for the combi.

 

[ELZ4742]

no more than a 3a in a boiler, as per makers spec.

 

[dingbat]

Is that not a 13A rated FCU? I'm prepared to be proven wrong, but should it not also be protected by a suitable MCB, i.e. a 10A?

No. The fuse in the FCU limits the load that can be applied downstream of it and hence the current that passes through it.

Also, wouldn't it be fun trying to run a 13A load on a 10A MCB?

But these fuses are changeable and I was planning on putting in a 3amp one. Is that not a good idea?

The MCB protects the cable that supplies the fused connection unit.

The fuse in the FCU protects whatever is downstream of it.

The fuses are supposed to be interchangeable, so you can fit one of the appropriate rating for whatever you propose to run from it.

 

[adwt2004]

Thanks dingbat, just didn't want to do it wrong. Thanks for your advice, and every one else too