17th ed consumer unit, which mcb for where?

guydewdney

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cant seem ti find any proper guidance on what circuits should be on rcd#1 vs #2..... Looking at doing upstairs on 1 and down on 2, with lights on their own rcbo(s) and the disabled lift on an rcbo. Still confused about cable (armoured, buried) to garage with garages own rcd.


Any pointers?
 

Meldrew2

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Lights on one, sockets on other. Otherwise you plug in faulty appliance and fall down stairs in dark.
 

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guydewdney said:
cant seem ti find any proper guidance on what circuits should be on rcd#1 vs #2..... Looking at doing upstairs on 1 and down on 2, with lights on their own rcbo(s) and the disabled lift on an rcbo. Still confused about cable (armoured, buried) to garage with garages own rcd. Any pointers?

Cable to garage above the ground and armoured... Otherwise it has to be buried to complex standards so future resident or workman doesn't put a power tool through it...
 

sallison1504

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17th edition says to apply discrimination. Upstairs lights, downstairs sockets on one RCD, and downstairs lights, upstairs sockets on the other RCD. If you don't know this, I would highly recommend you don't start playing with the electrics.
 
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guydewdney

guydewdney

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Thats what i thought, as if downstairs item blows rcd, it would be nice to have lights to be able to see whats wrong!

A very short bit of the outside cabling is twin and earth in a very inaccesable area. Then two core swa to garage and greenhouse (with their own earths and rcds). Decided against exported earth.

Thanks for the advice, but ive done all the electrics here, inc three phase, and five inverters. The last electrician couldnt trace a fault, and blamed 'leaking electricity'........... who would you rather trust? My last job was an aerospace electrical design engineer.
 

Meldrew2

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My last job was an aerospace electrical design engineer.

There's a few essential differences - but your skills should be more than adequate. A copy of the IEE "on site guide" to BS7671 might be a useful reference.

BTW "leaking electricity" sounds very strange - but could it be an expression for low insulation resistance between phase & earth?
 
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guydewdney

guydewdney

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No, the guy was just a moron. It turned out to be a roofing nail joining two of four conductors in a lighting circuit. So we just used the other two, unaffected, wires ( or rip down the brand new ceiling in a 40' long barn conversion.....) only runs one led gu10 fitting anyway.

17th ed spiral bound edition ordered from ebay for seven quid, lol.
 

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