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Outbuildings - multiple consumer units

Former Community Member
Former Community Member
Evening all,


In a situation where I'm shortly going to be rewiring a new house I'm moving into and am hoping someone can provide me with some clarity on the best way to provide power to multiple outbuildings. 

Essentially I had planned to install a main consumer unit indoors and then feed the outbuilding via an RCBO on this consumer unit, i.e. consumer unit to, twin and earth, to junction box internal, to SWA across the garden, to secondary consumer unit in outbuilding - repeat this 2 or 3 times to the various outbuildings I need power in. However when doing a bit of research on the subject there seems to be differing opinions on whether to do this or to install a Henley block at the main incoming supply and then come out of that with one feed to my 'main consumer unit' and another feed out to the 'secondary outbuilding consumer unit' or multiple consumer units. It never occurred to me that this was an option and frankly I'm in a muddle as to what the consensus is on best practice, some mentioning a Switched fuse also.


If anyone could give me their opinion on what the safest and best practice is i'd be extremely grateful! TIA
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  • Former Community Member
    0 Former Community Member
    Sounds sensible, perhaps I worded my original post wrongly, I've got no intention of putting any twin and earth anywhere outdoors. 


    My intention in the largest outbuilding was to have a 32A ring, internal lighting and garden lighting fed from the consumer unit, then for the other two smaller outbuildings I'll be wanting a 16A radial and lighting in each. I don't anticipate ever using anything like 32a or 16a in the respective buildings but if feeding 10mm SWA to the first and 6mm to the second cables are rated more than adequately


    With this and the other replies (thanks all) maybe I'll do Henley block - Fused isolator (40a or 60a) - 10mm SWA - RCD consumer unit (MCBs feeding all 1st outbuilding circuits & 2nd outbuilding Garage consumer unit) - 6mm SWA - 2nd outbuilding garage consumer unit (MCBs feeding 2nd outbuilding circuits & third outbuilding Garage consumer unit) - 6mm SWA - 3rd outbuilding garage consumer unit. The outbuildings are in a layout which makes it relatively sensible to have one feeding another to another, will end up being an L shape cable run. Doing the above should in my mind give me RCD protection through all the outbuildings -however if the 3rd has a fault all three will go out (maybe a split board with the feed to the next building not RCD protected but all the circuits in each outbuilding covered under the RCD section would resolve this?) 


    Anyone have any critique on the above? 

    Thanks again
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  • Former Community Member
    0 Former Community Member
    Sounds sensible, perhaps I worded my original post wrongly, I've got no intention of putting any twin and earth anywhere outdoors. 


    My intention in the largest outbuilding was to have a 32A ring, internal lighting and garden lighting fed from the consumer unit, then for the other two smaller outbuildings I'll be wanting a 16A radial and lighting in each. I don't anticipate ever using anything like 32a or 16a in the respective buildings but if feeding 10mm SWA to the first and 6mm to the second cables are rated more than adequately


    With this and the other replies (thanks all) maybe I'll do Henley block - Fused isolator (40a or 60a) - 10mm SWA - RCD consumer unit (MCBs feeding all 1st outbuilding circuits & 2nd outbuilding Garage consumer unit) - 6mm SWA - 2nd outbuilding garage consumer unit (MCBs feeding 2nd outbuilding circuits & third outbuilding Garage consumer unit) - 6mm SWA - 3rd outbuilding garage consumer unit. The outbuildings are in a layout which makes it relatively sensible to have one feeding another to another, will end up being an L shape cable run. Doing the above should in my mind give me RCD protection through all the outbuildings -however if the 3rd has a fault all three will go out (maybe a split board with the feed to the next building not RCD protected but all the circuits in each outbuilding covered under the RCD section would resolve this?) 


    Anyone have any critique on the above? 

    Thanks again
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