Wiring Shed

Shadow-Lord

Hi,

There will be a water booster pump, sockets and lighting in the shed.

There is an old type fuseboard in the shed, so no MCBs or RCBOs etc.

The fuseboard in the house is the same.

Which type wiring would be more suitable for the shed.



or

Randyleprechaun

I would think the 2nd option would be the nearest to being right. Although a 40A RCD would be more suitable with a 20A MCB of it for the sockets(wire sockets in 2.5). The size of cable coming from the house and the size of protective device should be given careful consideration also, as technically all devices should get smaller as you go downstream to give correct discrimination.

I can draw a suggested plan if you wish.

Shadow-Lord

Thanks for the info.
The consumer box is full with these in it.

Should I switch the 40 AMP RCBO for a 20 AMP RCBO and go with the second diagram.

If you have a different diagram which you think would be better, that would be great thanks.

jen85

would use the 2nd diagram.
you should change the 40a rcbo to a 20a rcbo as this is for a radial socket circut i take it and should not have a 40a fuse protecting it .
Also if the 16a mcb is souly for the pump id stick a 6a breaker on it although im sure youl have a 3a spur on it when people change fuses in a spur they tend to replace it with the nearest plug top and can end up putting a 13a fuse in it and if it pops again could damage the circutry in the pump.

davelerave

i would feed the booster pump via rcd as well .

Shadow-Lord

I am getting mixed replies here. Can anyone give a definite answer, please.

davelerave

there's a few possible permutations within the rules.i would simply plug the booster pump into an ip66 switched socket for ease of maintenance .

2011

I am getting mixed replies here. Can anyone give a definite answer, please.

The first thing you should do is give some information that will assist us with giving you accurate advice.

1) What is the size of the cable feeding the shed?
2) What type of cable feeds the shed?? (Is it an SWA?)
3) Is the cable buried in the ground?
4) How long is the cable run from the house to the shed?
5) What rating is the water pump? (In watts)

Once the questions above have been answered the next job is to size the main switch fuse for this sub board, and then protective devices for each sub circuit.
As mentioned in a previous post a 20A RCBO (B type 30mA) would be suitable for a radial socket circuit.

The regulations do not require a fixed appliance (such as a water pump) to be fed from an RCD (or RCBO), however doing this would provide additional protection.

i would simply plug the booster pump into an ip66 switched socket for ease of maintenance .

This would work too. MK make a great one. The one shown below even has a built in timer.

Shadow-Lord

The size and type of cable to the shed is unknown.
It was fitted a few years ago.
Its is underground and was put in for a welder.
Cable is about 20m from the house.

Water pump is 1.55 watts

davelerave

you should determine the 'capacity' of supply first(and test supply cable if unsure).should be easy enough .could be a 3*10 if it was for a small welder 20m from house but you would need to check

bauderline

Folks,

In the first diagram here we see a MCB fed off the RCBO which is also feeding a radial socket circuit. Is this safe an acceptable if the RCBO was suitably spec'd ?

P.

davelerave

Not really for final circuits like socket and a pump(in diagram),sockets overload knocking out pump mcb.You might see it if the rcbo was a main incomer for something like a 'tt' board or a caravan

bauderline

A 25amp RCBO should be fine for a radial circuit though ?

P.

mac_iomhair

one word of advice... get a qualified electrician and dont rely on the internet to give you the correct answers.