info needed on shed supply

[timwood1234]

I have been given some 3 core 4mm SWA cable 45 metres long, i have a sparky friend who is willing to supply my shed down the garden approx 35 metres away from my house fuse board.

He has said if i get the parts he will install free so what do i need ie a fuse size in the house? do i need a fuse board in the shed?

My sprky friend is in australia at moment so cannot contact him.

 

[sparkyspike]

That cable is only good for 20A*, so you will need to fuse down to 20A at the house, and use a garage board (16+6A fuse board) in the shed, or use a fused spur for the lighting circuit.

You need to ask your electrician about isolation and earthing, as these are both important when taking a supply to an outbuilding.

What are you doing in the shed (if that's not too personal a question!)? Is it just a standard wooden toolshed? Do you know what kind of supply/fusebox you have in the house? Do you know if you have RCD protection?

*16A max, if you are using the full length of cable.

 

[JohnD]

I know the chap you mean, he's often mentioned on here.

Best thing is to wait till he gets back, if you can't e-mail him.

 

[ban-all-sheds]

That cable is only good for 20A*

Not according to 4D4A.

 

[Taylortwocities]

My version of 4D4A doesn't say 20amps either

 

[ColJack]

I believe that he's calculated the load that corresponds to the max volt drop for that given length of run and given cable size.. ( hence why he lowers this to 16A when extra length is added.. )

 

[ban-all-sheds]

According to a certain P.Cook it is never acceptable to use a fuse or circuit breaker as a load limiting device...

 

[jockspark]

dudley moore said the same thing

 

[plugwash]

According to a certain P.Cook it is never acceptable to use a fuse or circuit breaker as a load limiting device...

The question then becomes where do you draw the line between an overload protection device and a load limiting device.

With a supply for say fixed equipment the design load is obvious (though you still have to decide how much diversity to apply) but with a general purpose socket supply it could be virtually anything depending on the assumptions you make.

 

[ban-all-sheds]

Simple - overload protection is for an obvious reason - to protect the cable. If you're trying to limit the load for other reasons then deliberately arranging for the protective device to operate isn't on.

 

[Taylortwocities]

Its a reverse cable selection process.

have been given some 3 core 4mm SWA cable

Normally you calculate the load & protective device (etc) and then select the cable required.... [/quote]

 

[scarypants]

Interesting topic, but back to a more serious point
when do!
Derek and Clive turn up?

 

[scarypants]

View media item 10865I knew they where on their way and not in Aussie with everyone else![/img]

 

[timwood1234]

I have had a look in my house fuse box and from what i can see its a MK sentry box, the main switch says 63amp 30ma so i take it thats an RCBO covering the whole box? next to the main switch is 4 other smaler switches x1 says 6amp when i turn it off the lights go off in the whole house, x2 say 32amp from what i can make out they do the plugs? and x1 says 40amp which does nothing i believe it had something to do with an old electric shower no wires out of this one.

So will that 40amp fuse be ok for my electrician to wire into or do i need to obtain a 20amp fuse? where would i get one?

 

[MasterAbacus]

Defo worth waiting for you mate to return until you buy anything... esp if your not sure where to buy a 20amp Fuse / Relay from.... pmsl....