Bringing electricity to garden room

Xcellor

Looking for a bit of advice. Planning to put garden room in back garden about 25-30 meters from house. I'm assuming that will need to connect into consumer unit rather than a spur off an outdoor socket ? Or what is the usual? I'm getting an electrician in just want to know if I can get ahead and run cable. Anyone who has done something similar? Will be 3 double sockets / 4 lights / electric heater and powering TV laptop cross trainer.

Cheers.

helimachoptor

I had a log cabin install in 2020, run of about 40m from the board to the cabin.

10square swa, has 8 downlights, two external lights, 4 double sockets.

in the winter there’s a 2000w heater and laptops/screens/lights on and no issues.

We got an extension built and the electricians said an isolator switch was now required so that was added.

in terms of costs, can’t really help as it was a friend and he did it for a few pints.

Xcellor

https://www.boards.ie/discussion/comment/122150805#Comment_122150805

thanks I was thinking 6mm would probably be enough. How did he route the cable from the box to outside, it's a thick cable!

helimachoptor

we had a converted garage where the box was. So over the garage roof and then drill through the brickwork, the box was pretty close to the exterior of the house so wasn’t very messy

Board Walker

I have a steel shed where i do a bit of cutting and grinding etc. I just came off a socket in the corner of the kitchen and ran a 4sq SWA underground.

It would be an absolute ordeal to get the CU as there is a steel RSJ int he kitchen. I have a 10A and a 20A RCBO in the shed protecting the two circuits.

Now this was acceptable once upon a time but not any more and i fully intend on running a new cable from the CU when we extend the sun room in two years time but technically its fine.

Xcellor

https://www.boards.ie/discussion/comment/122160436#Comment_122160436

I have a shed and ran a cable from outdoor electrical socket to a shed but this was much shorter distance and shed is only for chest freezer and a light but given the extra distance involved ~25 meters and having electric heater and a few other devices I want the proper job done here. Don't want new log cabin burning down the day after installation :)

Board Walker

https://www.boards.ie/discussion/comment/122168442#Comment_122168442

If you're that worried then just leave it to the professional :)

Mine was only 7 meters away.

I believe you will need armoured cable if you intend to run it underground. Will definitely be a sparks job.

Xcellor

https://www.boards.ie/discussion/comment/122168491#Comment_122168491

Yep ! Will get a professional to do it.

monseiur

Open trench about 18 inches (450mm) deep from house to garden room. Place SWA cable in trench, back fill half way up then lay warning tape in trench which reads ''Buried Electric Cable'' or similar, then complete back filling. If you have a concrete path cut a 3 inch (75mm) wide channel with con saw or angle grinder and chip out.

Depending on house layout etc. one option is to run cable up the exterior wall (perhaps near a down pipe to conceal) and into attic and down to CU unit.

Double check with your electrician re. size of SWA cable required and allow for volt drop etc.

Xcellor

https://www.boards.ie/discussion/comment/122171565#Comment_122171565

Attaching an image, the red box is where the consumer unit is and the opposing wall is probably the best route to bring it out as then it can run behind a wall along the garden edge. The cable would run above skirting below radiator and given its low down and behind sofa isn't really a massive eye sore.

I suppose the other option is to try and fish a cable up to the attic from ground floor and then come out on the side of the wall. Attic isnt very accessble though low pitched roof and with insulation i suspect it would be a pig to go down that route.

I dont see a neat option to run it at the front of house really.

Xcellor

wire route.jpg

image.

CrazyEric

https://www.boards.ie/discussion/comment/122173857#Comment_122173857

Where is the incoming meter box??

Xcellor

https://www.boards.ie/discussion/comment/122176011#Comment_122176011

The meter box is on the other side of the house so would be further away. I hadn't really considered that as an option but is it possible to take another feed from that and connect to a new customer unit in the garden room?

drury..

https://www.boards.ie/discussion/comment/122176063#Comment_122176063

No not allowed

monseiur

Your suggestion seems all wrong to me. Remember we're talking about an SWA cable which may be the size of a 3/4 inch water hose (depending on load) not something the size of a phone cable. Have a chat with your electrician most are imaginative in cases like this and experienced in pulling cables under floor boards, up cavity walls, across awkward attics etc. - it is their, almost, daily bread & butter.

Board Walker

https://www.boards.ie/discussion/comment/122176063#Comment_122176063

Christ no. The only thing that can be tapped off of that is EV Chargers and theres a special set up for it.

Just let the spark at it.

Calahonda52

https://www.boards.ie/discussion/comment/122188282#Comment_122188282

an FYI undate to regs, meter box for ev's no longer allowed

Xcellor

https://www.boards.ie/discussion/comment/122183319#Comment_122183319

ya I suppose I'm just wanting to make it as straightforward as possible.. the consumer unit appears to channel all cables upwards, is it the norm that at least some of them would go through wall cavity to attic? I have a cable fish if I could investigate that and find the exit point in the attic might be the best option. Attic space is really limited.

Xcellor

I had a look up in the attic to see if I could figure out where the cables from the consumer unit run to in attic and discovered following

20240529_102522.jpg

This looks like where the majority of cables are running through, some quite heavy gauge cable which I'm assuming are for the electric shower and maybe immersion, twin earth, coax and some old alarm cable.

This route looks the easiest to get a cable from. Ill remove a bit more of the plasterboard and see if I can fish something through to the top of the consumer unit. then the cable could run through attic and come out at the side of the house which would be a neater job.