One for the electricians.

[Diggerg]

Looking to run a supply to my shed. I have a spare dis board that used to run the storage heaters with 5×16 amp mcb's. The run is about 15 metres and I plan to install a 40 amp garage unit in the shed. Can I remove mcb nearest the main switch and replace with a 40 amp. Was planning on using 10mm twin and earth.

 

[london_lhr]

Hi,
I am NOT an electrician but you can use 6mm2 twin and earth for up to 9Kw.
You should also use armoured cable buried "X"mm deep from your house to your shed. (not sure how deep though!)
From the consumer unit in your shed, you can run 6mm2 twin and earth to your control panels or plugs that are rated to handle the current.
I stand to be corrected on this information.
You would probably only need a 30Amp mcb, depending on the amount of current you plan to draw from the unit.
My setup has two 5.5Kw elements with only ONE in use at a time.
Current draw is approx 23Amps in my situation.
Hope this info helps.

 

[Diggerg]

Hi. Thanks for the reply. Will be coming out of the did board straight through the wall and conduit along house then across a 8 foot gap with a straining wire and into shed.

 

[GAZ9053]

Is your main DB RCD protected? As an external building req protection.

 

[Diggerg]

No as the garage unit will have a rcd in it. The board I am using is a spare one to main board as it's the old economy 7 board.

 

[GAZ9053]

Fair enough, personally i prefer RCD at the source so it protects the whole install but regs just req rcd protection if you did at source you do not need one in the shed.

 

[Diggerg]

Was going to run ring main off the 32 amp breaker and lights and stc1000 off the 6amp.

 

[GAZ9053]

what are you powering with the stc? will it pull more than 6A? ring and lights ok for size, 2.5 T&E for ring and 1.5 T&E for lights?

 

[danb]

I have t + e from the cu through the house then into SWA uup to the shed clipped. I have the supply from a rcbo on the non RCD side. I could have gone with no RCD until the shed cu but I'd prefer the protection on the cable run especially with younguns around.

Atm I have 2.5mm off a 20a rcbo which is fine for one element plus the fridges but I'm in the process of going to a 10mm run so Ihave no rrestrictions on brewdays etc.

 

[Diggerg]

Stc will be running fermentation fridge. I could put rcbo in cu and still have rcd in shed unit.

 

[danb]

I have rcd in the shed cu also and when tested it was fine.

 

[LeithR]

One word of warning.
It sounds like you are planning to do the work yourself which I applaud. There is a BUT however, you might be invalidating your house insurance if you do not get a qualified electrician to inspect/test and sign off/certify the work after you have finished.

 

[GAZ9053]

One word of warning.
It sounds like you are planning to do the work yourself which I applaud. There is a BUT however, you might be invalidating your house insurance if you do not get a qualified electrician to inspect/test and sign off/certify the work after you have finished.

Yes the work does come under part P of the building regs. If rcbo in house then RCD is not req in the shed they could also false trip with 2 on the circuit

 

[Diggerg]

I have several friends who are sparkys that can test it. Just doing install then get it tested. I was an electricians mate for 5 years but just wanted to be sure.