If you have an RCD at the garage end, you won't have discrimination between that and the RCBO. Do you need an RCBO (because of cable installation method)? Can you replace it with an MCB?
Less than 3m span so therefore no additional support required. What is the height of the cable? I'm assuming you supplied it via an RCBO because you have no RCD in the main CU and wanted to protect the cable?
Yes height of cable is 3.5m high, and the span across from house to garage is less than 3m so i have not put supports on. Got it on RCD IN GARAGE and 20A mcb and 6A mcb sockets/lights but the main run back to the main consumer board i have put on a 32A rcbo.
As said above, no discrimination between the RCD in the garage and the RCBO in the main consumer unit. I'm no expert but I wouldn't have thought the SWA feeding the garage needed RCBO protection?? Daz
Yeah I understand no discrimination but meeting requirements of 17th edition split boards will be rcd protected on one side and the main switch side either on rcbo's or another rcd so for sake of the assessment it will just having double protection on the rcd side, and i have 32 A protection on 4mm cable and 20 A protection on 2.5mm cable after the garage consumer board.
well, as regards assessment, i would explain that you realise that there is no discrimination, but lacking a hi-integrity CU, that's the best you could do .
Yeah I understand no discrimination but meeting requirements of 17th edition split boards will be rcd protected on one side and the main switch side either on rcbo's or another rcd so for sake of the assessment it will just having double protection on the rcd side, and i have 32 A protection on 4mm cable and 20 A protection on 2.5mm cable after the garage consumer board.
Providing that you're not on TT earthing and that the cable to the garage is armoured or surface run, then you don't need the RCBO at the house end. Change it for an MCB.
No offence intended, but you need to start thinking what's actually required rather than just doing what's "standard".
No such thing as double protection, more like pain in the bum I'll never know which RCD has tripped. Like that it won't comply and thats not good for an assessment...?
At least being an RCBO you wouldn't affect the rest of the installation. I've noticed over the years that many people with a fully RCD protected CU take the supply out then add another RCD in the outbuilding, and to be honest I've never known it to be that much of a pain unless someone very accident-prone lives there
At least being an RCBO you wouldn't affect the rest of the installation. I've noticed over the years that many people with a fully RCD protected CU take the supply out then add another RCD in the outbuilding, and to be honest I've never known it to be that much of a pain unless someone very accident-prone lives there
Fair one, just had 12 years of sparky stuff in the forces takes a bit of time to get used to all these regs and assessments but yes cause it is protected by an RCD at the garage will just have it on a 32A MCB at main board. Cheers for help!
One point if your trying to impress the assessor. I know the 3m unsupported is in BS 7671. However I always support them. A catenary is only a few quid and it makes the job more professional. We`ve all seen damaged unsupported cables even over <3m.. Just a thought.
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