anouther pir question

[Matty o]

Did a pir to day and found the shed was fed from a 16 mcb in the fuse-board in the house then wired in swa to a rcd in the shed then to a socket.

Now this doesn't feel right but cant find a reason why not
you can isolate the socket by using the the rcd locally or at the house the cables protected by the mcb ans as it swa that's fine

 

[telectrix]

is it 2.5mm SWA? as long as cpc intact and readings within limits. OK.

 

[malcolmsanford]

I have to be honest Matty I read this now 3 times and can not see if anything, what is wrong with the circuit. But then it as been a long day out here lol

What don't feel right mate.

 

[telectrix]

it's just a radial with the RCD at the point of use.

 

[malcolmsanford]

Yes see what your saying Tel MCB is providing the SWA with fault/overload protection ....................to the RCD enclosure but your worried about overload protection for the cable and socket outlet?

 

[telectrix]

i'm not worried it's on a 16A MCB at source

 

[malcolmsanford]

I know regulation 433.2.1 specifies that where a reduction in CSA or method of installation, type of cable or conductor, or enviromental change, then overload device should be fitted. I suppose there could be a point argues on several of those cases.

But I agree with you Tel as long as the cable either the SWA or the cable after the RCD can carry 16amps then reg 433.3 can be used.

 

[telectrix]

that's why i asked about the size of the SWA. i would have thought it would be 2.5mm coming off a 16A. if it is, then the circuit shouls all be 2.5. as long as the socket ain't wired in alarm cable!!!

 

[Matty o]

Yes its 2.5 and i was just having a bad day.I would of put a 16a mcb with the rcd and a 20a mcb in the house but like your say everything is covered, the overcurrent is provided by the 16amp mcb at the house end.

 

[SirKit Breaker]

i'm not worried it's on a 16A MCB at source

And its mechanically protected.