2.5 radial on 25A breaker?

[cornburn]

I got to a job on Friday and the board they had put in in 2000 has a 2.5 radial circuit on a 25A breaker? Ref method C, all cabling is in the walls or in conduit. I need to add several sockets tomorrow, do I have to change the breaker to a 20A to do this or am I missing something that could have been taken into account when the circuit was designed? It's only feeding one room with about 15 sockets (only a couple in use) and a water heater next door for tea on a fused spur.

It will have been on rewireables before the board was changed so seems odd they would have put a 25A breaker instead of a 20A. Also I would obviously prefer to minor works it for the small job it is instead of having to try and find a breaker to suit and do a full installation cert. Any thoughts anyone?

 

[acat]

Dont see a problem with that if its reference method C from start to finish CCC of cable is 27amps and 25amp MCB protects cable.


Chris

 

[cornburn]

Sorry my bad, meant not ref method C. It's all in walls and ceiling or in conduit so a mixture of Ref method A and B, so 18.5A or 23A. Doh! Was hoping to get hold of certs from when the board was changed to see if there was a note on there explaining but looks like no chance of that. Would you downrate the breaker or just stick them in and minor works cert it? I could always stick my 3 extra sockets behind a 13A FCU as they'll only be pulling about 3A anyway, just concerned about how much responsibility I'm taking on for the rest of the circuit.

 

[Sintra]

Cover your backside and change to a 20A.

 

[Guest123]

As it's a socket outlet radial circuit, not a fixed load I would definately downrate to a 20A MCB.

 

[acat]

Sorry my bad, meant not ref method C. It's all in walls and ceiling or in conduit so a mixture of Ref method A and B, so 18.5A or 23A. Doh! Was hoping to get hold of certs from when the board was changed to see if there was a note on there explaining but looks like no chance of that. Would you downrate the breaker or just stick them in and minor works cert it? I could always stick my 3 extra sockets behind a 13A FCU as they'll only be pulling about 3A anyway, just concerned about how much responsibility I'm taking on for the rest of the circuit.

Inwhich case I withdraw my last comments and go with the rest 20A MCB have fun filling out the paperwork.


Chris

 

[cornburn]

Bugger. That's what I was thinking. Can't see why the hell they would have used a 25A in the first place? There's no need for what's on it either and surely 16th edition ref methods and max cable capacities still wouldn't have allowed this? Board was updated by a large local contractor about 8 years ago.