Adding new ring main to shed

[maturin23]

Hi all,

I'm considering putting in an additional ring main in my shed/summerhouse that doubles as a two-person office.

We're about to insulate the walls/roof and now would be a good time to put extra sockets in. Currently using extension leads and 4 way blocks which is messy and potentially unsafe.

I'm planning on a group of eight sockets by each desk (2) and a group of six by the server.

There are 6 blank 'slots' on the Consumer Unit.

Most of the sockets will be powering PC/monitors/routers. Perhaps a couple of electric radiators and a kettle.

The power cable from the house to the shed was specced to cope with a kiln and the main fuse on the shed Consumer Unit is rated at 100A, so I think we've got enough capacity.

I'm keen to try and do this myself - any advice?

[Rosscow]

Don't electrocute yourself

[Ganglandboss]

maturin23 said:

Hi all,

I'm considering putting in an additional ring main in my shed/summerhouse that doubles as a two-person office.

We're about to insulate the walls/roof and now would be a good time to put extra sockets in. Currently using extension leads and 4 way blocks which is messy and potentially unsafe.

I'm planning on a group of eight sockets by each desk (2) and a group of six by the server.

There are 6 blank 'slots' on the Consumer Unit.

Most of the sockets will be powering PC/monitors/routers. Perhaps a couple of electric radiators and a kettle.

The power cable from the house to the shed was specced to cope with a kiln and the main fuse on the shed Consumer Unit is rated at 100A, so I think we've got enough capacity.

I'm keen to try and do this myself - any advice?

What is the size and length of the cable run to the shed? what size breaker protects the cable to the shed? Is there a consumer unit in the shed?

If you add any new circuits, it will be considered notifiable under part P of the building regs.

[maturin23]

Starting in the shed there is a consumer unit with individual circuits for the kiln, the existing 6 sockets and the lighting. There a 7 unused spaces for RCDs.

The shed unit is connected to the house via a 25m run of 30mm diameter armoured cable (I think it's rated at 90A). This was professionally installed to power the kiln and cost well over a grand.

The cable comes into a small Hager unit in the house with a 63A/30mA RCD.

This unit connects to the meter (ie not through house CU).

[sjj84]

Can you not extend the ring that is already in the shed? You're allowed to add sockets into an existing ring without the worry of Part P.

[megaphone]

The fact that you have to ask basic questions means you shouldn't be messing with electrics. However putting in sockets is not rocket science, you'll need some 2.5mm twin and earth and the suitable breakers for the consumer unit, 32 amps maximum. You could run the whole lot off one ring however I would put the server on it's own ring.

I suggest you run in the wires then get an electrician in to connect up.

[MGTS]

Two thoughts, not particularly related to your question but point well worth thinking about:

"Home plug" adapters for Internet access over your electricity circuits probably won't work down to the shed on this different circuit (they dont on mine) which leads me on to the next point, which is I would install a dedicated Internet cable and phone line cable at the same time as putting electric cable in. These cables will cost maybe twenty quid but will save you a whole host of troubles in the future

[tr7v8]

megaphone said:

The fact that you have to ask basic questions means you shouldn't be messing with electrics. However putting in sockets is not rocket science, you'll need some 2.5mm twin and earth and the suitable breakers for the consumer unit, 32 amps maximum. You could run the whole lot off one ring however I would put the server on it's own ring.

I suggest you run in the wires then get an electrician in to connect up.

I'd suggest a UPS for the server, assuming it is business critical. Dependent on server this may need a hardwired or different feed.

[maturin23]

Megaphone - you may be right, but I'm interested to find out how involved it may be.

I'm fairly capable when it comes to car electrics and microsoldering and I can follow instructions carefully. I also know when to call in a pro

Re phone line and internet; good call, but we already have a dedicated ethernet cable to the house and all our telephony is done via IP.

We already run the server of a UPS, but if the power goes down so does our VOIP system (we just use mobiles instead). Business is low volume high margin stuff and this office is admin only so a little down time is not enough of a problem to warrant significant extra spend.

[Brite spark]

megaphone said:

The fact that you have to ask basic questions means you shouldn't be messing with electrics. However putting in sockets is not rocket science, you'll need some 2.5mm twin and earth and the suitable breakers for the consumer unit, 32 amps maximum. You could run the whole lot off one ring however I would put the server on it's own ring.

I suggest you run in the wires then get an electrician in to connect up.

2.5mm may be too small or need to be down rated at the breaker if the shed is insulated, and the cables are in contact with the insulation.

[Brite spark]

maturin23 said:

Starting in the shed there is a consumer unit with individual circuits for the kiln

The shed unit is connected to the house via a 25m run of 30mm diameter armoured cable (I think it's rated at 90A). This was professionally installed to power the kiln and cost well over a grand.

The cable comes into a small Hager unit in the house with a 63A/30mA RCD.

This unit connects to the meter (ie not through house CU).

How much power does the kiln use? Is it one the same supply as the house (from the meter)

Is the 63A Hagar board feeding the shed?

Where have you got the size of the swa as 30mm (is this a guess of conductor size or overall diameter of swa) and rated current of 90A from?

Have you got a water and gas feed to the shed from the house supply?

Edited by Brite spark on Wednesday 10th October 11:29

[maturin23]

Brite spark said:

How much power does the kiln use? Is it one the same supply as the house (from the meter)

I don't actually know (it's the wife's) but it's not been switched on for 4 years! There will never be a point where we are in the office with all PCs/heaters/kettle running AND the kiln being fired up. It's on a 40A RCD. The house and shed are powered by one mains cable coming into the house (one bill). This splits after the meter.

Brite spark said:

Is the 63A Hagar board feeding the shed?

Yes - just the shed.

Brite spark said:

Where have you got the size of the swa as 30mm (is this a guess of conductor size or overall diameter of swa) and rated current of 90A from?

Size is the overall diameter and rating is based on what I can recall when it was installed. I may be wrong as the main RCD in the shed is 100A.

Brite spark said:

Have you got a water and gas feed to the shed from the house supply?

No - neither (is that question relating to earthing?)

I think this might be getting a little involved - the kiln is never used but the shed has capacity to power it AND we're already using what we need for the office (this is about replacing a few 4 block extension cables with some more wallk sockets.).

I think I'll just get a sparky in, business is flying so the cost is only a pride issue - if that makes sense!

[mattdaniels]

As mentioned, it needs to be Part P certificated so you can't realistically DIY. (if all the wiring is "get attable" and you have a friendly sparks you could in theory DIY up to the consumer unit then get the sparks to come in, do the final connection and test everything and sign it off but they are not supposed to do this IIRC).

One thing you might consider is a separate consumer unit for the outbuilding itself, which can be fed from the main supply or switched to a generator supply, depending on how business critical your stuff is.

[BigBen]

MGTS said:

Two thoughts, not particularly related to your question but point well worth thinking about:

"Home plug" adapters for Internet access over your electricity circuits probably won't work down to the shed on this different circuit (they dont on mine) which leads me on to the next point, which is I would install a dedicated Internet cable and phone line cable at the same time as putting electric cable in. These cables will cost maybe twenty quid but will save you a whole host of troubles in the future

Homeplug adaptors should work across circuits, there is nothing other than distance to stop them working between properties on the same phase, which I presume is interesting in some blocks of flats.

However a dedicated line will be miles better