Radial Circuit to Garage Spur

Discussion in 'Electricians' Talk' started by RelayUK, Feb 5, 2020.

  1. RelayUK

    RelayUK New Member

    Hi all,

    My house has an odd configuration, each room has a 15amp radial circuit for the sockets and two sockets per room.

    I want to get power to my attached garage.

    I was thinking of connecting from a socket in the nearest room to the garage and put in a consumer unit. The consumer unit will run the garage sockets.

    I noticed consumer units have a 64amp or 32amp RCD master switch. Does this matter as the radial would trip anyway? I'd use a 16amp RCD for the sockets.

    Just for information, the garage will run a freezer, washing machine, dryer, and the odd tool. If you've read this far, I should point out the main house fuse board uses fuses so it's not RCD protected - I'll get this upgraded in the future when I can afford it, but power to the garage is needed ASAP.

  2. Dam0n

    Dam0n Screwfix Select

    I'm not a sparky but that seems like strange wiring

    Are your sockets taken off your lighting or something?

    Can you not run to the garage using a spare way in the cu? If not, I would use this time to upgrade the cu and add a separate way for the garage.

    What you plan to run in the garage will probably trip a 16amp mcb if run together. Add to this 2 more sockets in use and you've easily got an overload situation. You'll be replacing fuse wire every 5 minutes.

    Also, I'm pretty sure you'll need to be rcd protected and even if not you should sort that out as a priority anyway.
  3. RelayUK

    RelayUK New Member

    Thanks for the feedback. The lights have their own circuit, as does the usual things like cooker, boiler, shower. The house has 4 zones (rooms) each with a 15amp fuse. I will be upgrading to a consumer unit with RCD as soon as I can and I'd like to run the cable from the garage to that new unit, but that can be done when that job happens.
  4. Dam0n

    Dam0n Screwfix Select

    Why dont you just run a extension cord from one of the sockets to the garage and connect everything up for the moment. You'll get 13amps but that's not much less than the cu is capped at and at least if it blows it blows a plug fuse rather than the fuse wire for the house. Then when it's time to do the cu do the garage properly at the same time.

    Seems excessive to spend all that money on a cu with proper ways for the garage and to just connect it up to the back of a socket with a 15amp fuse.
  5. Hans_25

    Hans_25 Screwfix Select

    If you have radial circuits for the sockets on a 15amp fuse, why not just extend a radial (or two) into the garage and add sockets to it. (or as Damon has just said, add an extension lead!)

    Sounds like your setup could do with a bit of updating, adding RCD protection would be a start.
  6. Comlec

    Comlec Screwfix Select

    As a temporary measure, until your CU upgrade, extend your radial circuit to the garage and put in one of these
    Then add a few of these to the load side of the RCD/FCU
    Hans_25 and RelayUK like this.
  7. RelayUK

    RelayUK New Member

    Thanks all,

    I'd love to just run an extension cable but unfortunately it would cross the hallway and be a trip hazard and could also get caught in the door and damaged.

    The reason for putting an RCD in the garage is partly so I can isolate the garage and protect it with an RCD ASAP. Later on the garage consumer unit will be running other stuff like a Ring trnasformer, PoIP, and other low voltage systems.

    I know I need to RCD protect the house, and I will, but I've been quoted £550 + vat + £150 earthing and I don't have that just yet (lots of other stuff needs doing and I just moved in).

    The question I guess is, will running the garage consumer unit off a 32amp RCD cause any problems if, for example, I managed to load 20amps in the garage. My thoughts are that a fault would trip the RCD, and an overload (in this case 20amp) would blow the fuse in the main board.
  8. RelayUK

    RelayUK New Member

    I like that solution, it would solve my problems. RCD protection and no overloading guaranteed. A temporary fix until I get a new main consumer unit for the house- thank you

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