Garage supply

Discussion in 'Electricians' Talk' started by MechanicalDan, May 25, 2018.

  1. MechanicalDan

    MechanicalDan New Member

    Hi all. I'll start this by saying I'm not an electrician, I am however a vehicle tech specialising in auto electrics and hybrid/ev vehicles (300vdc with 3ph inverters) right.. with that out the way I'll begin.

    I want to add a shower supply and a garage supply. I have an 80a one supply to a split load board (1 spare way on the main switch side). I had an electrician out who quoted but I'm not sure his design is "man" enough.

    His design was got a 50a rcbo in the spare way. Run 10mm swa (14 meters clipped direct) to a 6 way board to run the 9.5kw shower. 2 dbl sockets and a 40a mcb to run another 12 meters underground to the garage (6mm swa) which will have another board with a TT.

    Im intending on doing some welding, spraying and installing a 4 post lift in the future.

    My worry is, if my compressor starts while someone is in the shower it'll trip the 50a supply.

    My idea was to install a 4 way ip65 board next to the meter cabinet (connected using a Henley block and meter tails) then have a 100a main switch and 2x 50a mcbs.1 to the shower cu. 1 to the garage. 2 runs of 10mm swa (clipped direct for 10m then buried under concrete).

    Which way would you guys go?

    Im getting either building control (add they're coming on site anyway for the garage build) or a spark with 3rd party to sign it off but I'm still designing at the min.

    Sorry for the long post.

  2. peter palmer

    peter palmer Well-Known Member

    I would certainly go the Henley block way, 2x switch fused isolators would be better than a pair of 50A MCBs but the cost and space are a lot more. Why is the shower feed so far away from the original mains unit? is it in the middle of the garden or something.
  3. MechanicalDan

    MechanicalDan New Member

    The shower is diagonally opposite the cu and meter. I either take up all the floors and fish across a single story pitched roof with no access or go around the outside.. I'll look into the switch fuses. 50a each sound ok? I think i could go closer to 60a but it seems pointless given my dno fuse is 80a.

  4. Coloumb

    Coloumb Well-Known Member

    What's the rating of the cut out? How many watts for the shower and comp? by rule of thumb and mcb will carry 1.45 its load for an hour. Do you really expect to draw around 72a for that long? I expect your leccy bill will be stupendous if you do.
  5. MechanicalDan

    MechanicalDan New Member

    I've just bought a 9.5kw mira shower. I may in the future buy an electric or hybrid car. They pull 10a for up to 6 hours straight. So having the capacity on either shower or garage supplies would be handy.
  6. Coloumb

    Coloumb Well-Known Member

    So that's around 50a and no one stays in the shower more than 15 minutes or so
  7. Coloumb

    Coloumb Well-Known Member

    Also you have just a shower in some sort of out house?
  8. MechanicalDan

    MechanicalDan New Member

    The outhouse is the other side of the bathroom wall. So I could just drill through and I'm there.
  9. MechanicalDan

    MechanicalDan New Member

    Been thinking about this and looking at what materials come up as site left overs.. Could I use 10mm 4 core with a pair of mcbs in my house cu then what is effectively a split load board in the outhouse with 1 pair feeding the shower and sockets on an rcd then the other pair going into a main switch then out to the garage on 10mm 2 core?

    Just a thought.
  10. Peterdevon

    Peterdevon Active Member

    Why not just run 25mm split con from your 100A switch fuse to the first board

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