One for the electricians

[mushtafa]

It's almost time to run power to my new shed and I have two options;
1. Run a separate circuit from the consumer unit.
2. Install fused spur from the kitchen circuit.

Is this spur suggestion OK? Or shall I just bite the bullet and install a new circuit?

 

[thezappa]

Not an electrician but surely a feed from the consumer unit is going to be safer.
If you are having a light and potentially a power outlet, having its own fuse on the distribution board is better.

 

[gpuerrilla]

How much power are you needing in the shed?

Typical install would be run SWA from a small DB.

 

[The Artfull Bodger]

Not an electrician, but whenever i've worked in places with remote power, it usually has its own consumer unit. Hopefully an electrician will come by and advise you, otherwise speak to an electrician. Working on gas and seeing some peoples ideas of what is acceptable can occasionally be borderline lethal! Electrics can be the same.

 

[mushtafa]

I agree, the consumer unit run will be safer, but it's more work, more wire, and more expense. If a pro said the fused spur was acceptable I would take the easy route.

As for power usage, a socket or two, a strip light, and perhaps a couple of LED downlighters. Nothing serious. It's a storage shed, not a workshop. May plug some power tools into it, but nothing a normal extension lead wouldn't handle.

I'll be running armoured cable either way, it's only 1m from the house, but it'll be buried under the slabs

 

[LuckyBenski]

Fused spur can only have 1x point (single or double socket) on surely.

Add an RCBO to your consumer unit and another RCD/RCBO setup to a little CU in the shed, IMO.

 

[robj20]

Fused spur can only have 1x point (single or double socket) on surely.

Add an RCBO to your consumer unit and another RCD/RCBO setup to a little CU in the shed, IMO.

RCDs don't with like that, pointless having more than one on the same circuit.
If you wanted an RCD in the garage you would need to take a feed from the main consumer unit before the RCD.

 

[200sols]

Fused spur can only have 1x point (single or double socket) on surely.

Add an RCBO to your consumer unit and another RCD/RCBO setup to a little CU in the shed, IMO.

Fused spur can have as many points after the fuse as you like, you could have 100 double sockets if you want but all limited to that 13a fuse.

 

[200sols]

I agree, the consumer unit run will be safer, but it's more work, more wire, and more expense. If a pro said the fused spur was acceptable I would take the easy route.

Why would it be safer? The reason to run from CU a dedicated supply would be if you wanted to draw lots of power, it doesn't sound like you want to do that so a 13a fuse spur is more than acceptable. The safety aspect comes from running the cables and terminating the armour correctly.

 

[aVdub]

I agree, the consumer unit run will be safer, but it's more work, more wire, and more expense. If a pro said the fused spur was acceptable I would take the easy route.

As for power usage, a socket or two, a strip light, and perhaps a couple of LED downlighters. Nothing serious. It's a storage shed, not a workshop. May plug some power tools into it, but nothing a normal extension lead wouldn't handle.

I'll be running armoured cable either way, it's only 1m from the house, but it'll be buried under the slabs

Not a Sparks, have installed rings, radials and fused spurs (all signed off) and if only 1m from the house and not drawing more than 13amp, then imo fused spur is more than enough and as @200sols wrote above "Fused spur can have as many points after the fuse as you like"

 

[thebandit]

One point on the fused spur, you are more likely to get RCD trips (earthing/ residual current ) on an outside cable run and this would take out the kitchen ring (and any other on the same busbar) with fridge and freezer etc, so whilst the spur is technically legal from a regs view point its not best practice. As people have said above a sparky would probably install a new CU close to the point the cbale exits the building for the outside run, but a new ring/spur from the existing CU not on an existing circuit (RCD) with its own RCBO (MCB and RCD in one) would be next best.

 

[Mysterae_]

The handy thing with a spurred feed tripping something in the house is then at least you know something is tripping in the shed , otherwise how would you know if you don't go in there very often. Important if you have a freezer or something you don't want to lose power to.

A spur is fine, it's what I did. Broken in to the back of a socket in the garage, ran it to an IP rated enclosure to terminate and run the SWA cable from:

Then took the SWA underground (compliant with the regs) to the shed 5 metres away where I installed a mini RCD unit:

Two circuits - one for lights, one for sockets. I ran the cables in the shed in copex for tidiness and protection.

The only issue you may run in to is when testing the earth, you may need an earth rod planted in the ground but for your short run I'd be surprised. Make sure you get it tested.

A new circuit from the consumer unit is the ideal and best practice but the effort and cost of doing so was just to much - chasing numerous walls, then plastering and decorating.

 

[Cornubia]

By far the best solution is to install a new circuit from the consumer unit. If done correctly this mitigates further hazards and nuisance from a fault in the shed impacting other circuits in the house e.g. a fault in the shed tripping the kitchen circuit and causing the freezer to defrost.

Depending on the size and load required in the shed this could be accomplished in a couple of different ways:

1) Submain from the consumer unit in the house to a consumer unit in the shed with separate lighting and socket circuits. These final circuits should have RCD protection meaning the submain can omit this requirement if installed appropriately e.g. earthed mechanical protection. The benefit from this is any fault in the shed would be self contained and allows for multiple circuits in the shed depending.

2) Circuit from the consumer unit in the house feeding sockets and lighting via fused spur in the shed. If installed from a RCBO in the house consumer unit this would again ensure any faults in the shed are self contained whilst keeping the installation cost lower by omitting the second consumer unit.

Either way the addition of a circuit in notifiable works (Part P) and should always be carried out by a competent person.