Advice on running power to shed

stiofan85

Hi folks,

Putting in base for a cabin this weekend and digging in conduit for services ahead of that. For electricity I have a couple of options I would appreciate guidance on. Cabin will have washing machine/dryer & need to power some lights and maybe a couple of power tools but nothing heavier. Length of garden is 12m, run through house is ~16m, so say 30m all together.

I've 6sqmm T&E (older type with 2x6 + 1x2.5 earth, unsheathed) run through house from CU to kitchen. It is not connected yet to CU yet - I put it in place in case we put in a cabin in future. I'm trying to figure out best option for running power to the cabin.

Option 1: I have a load of 6sqmm T&E left over which I could run in some 32mm PVC pipe I have left over. Buried down to 2 feet or more if I can get down that far. Lay down warning tape above etc...

Option 2: Run 6sqmm SWA in the 32mm PVC, 2ft down + warning tape.

Option 3: SWA clipped to block wall down length of garden

Obviously will be getting REC in to wire up the cabin with a distro board etc... but just want to sort out the services. Since I've a load of T&E left over it seems wasteful to not use it, but SWA is safer-is it necessary? At 2 feet down below a lawn in a thick PVC pipe I would imagine it is quite unlikely to be damaged. I'll be digging a deep trench to run water down in a separate conduit anyway. Also conscious that the T&E I have is the older type, which may rule it out regardless.

Another question - is it safer to have electric come up under the cabin, or at the back and run up the back wall and into distro board? Under seems less likely to be damaged, but more difficult to access long term.

And finally, should I have an earth rod installed at the cabin? I've seen this mentioned on a couple of sites.

Thanks

Risteard81

stiofan85 wrote: »

Option 1: I have a load of 6sqmm T&E left over which I could run in some 32mm PVC pipe I have left over. Buried down to 2 feet or more if I can get down that far. Lay down warning tape above etc...

Aside from the fact that T&E is completely and utterly unsuitable for burial, the use of the old type T&E cable is prohibited.

You should involve your REC to design this installation for you.

stiofan85

Risteard81 wrote: »

Aside from the fact that T&E is completely and utterly unsuitable for burial, the use of the old type T&E cable is prohibited.

You should involve your REC to design this installation for you.

Thanks.

stiofan85

I'll run the pvc pipe under the foundation. If REC is happy to use it then fine, if not it's not a problem and it is just there

2011

I would only consider using SWA for this. If my memory serves me correctly these cables must be buried at least 3 feet deep to comply with regulations. Without doing any calculations (but with the benefit of experience) I am reasonably sure that a 6 sq. cable would be undersized for the load you have described. The electrical aspect of this project needs to start with a proper design. Penny pinching can result in cutting corners which can have nasty consequences. Please remember you are dealing with a potentially lethal voltage.

stiofan85

2011 wrote: »

I would only consider using SWA for this. If my memory serves me correctly these cables must be buried at least 3 feet deep to comply with regulations. Without doing any calculations (but with the benefit of experience) I am reasonably sure that a 6 sq. cable would be undersized for the load you have described. The electrical aspect of this project needs to start with a proper design. Penny pinching can result in cutting corners which can have nasty consequences. Please remember you are dealing with a potentially lethal voltage.

Thanks, all is understood. I have zero desire to penny pinch, but I do not want to waste either, hence asking.

If something larger is needed, then it'll have to come from the board around the outside of the house. In that case I won't bother running the channel in the ground and just run water, which is less digging and let the REC worry about the wire size. I threw the 6sq as a last minute "just in case" before I closed up the floors and put in the kitchen. It's there and if the REC wants to use it and sign off then fair enough.

I appreciate the advice.

Risteard81

A REC can only sign off their own work. So even if appropriate cable had been used (which it has not) a REC still couldn't certify a cable laid by someone else not under his direction and supervision. (The exception to this scenario being upon the successful filing of a Change of Contractor application.)

stiofan85

Risteard81 wrote: »

A REC can only sign off their own work. So even if appropriate cable had been used (which it has not) a REC still couldn't certify a cable laid by someone else not under his direction and supervision. (The exception to this scenario being upon the successful filing of a Change of Contractor application.)

Thanks. This is very clear.

stiofan85

A couple of months later and the cabin is in and all is looking good...except I can't seem to contact a REC. Is it a difficult time of year or is a small job like this not worth it? Can't seem to get through and anyone I've left messages with has not called back.

If anyone can recommend a REC via PM near Dublin 12 that would be appreciated also.

Thnks

stiofan85

Thought I'd follow up:

Struggled to get a sparks in - most were reluctant when they asked about running cable along the wall to the back of the garden. The one quote I got was for €900 and I agreed to it, but then he vanished.

Spoke to a friend of a friend who's an electrician and he advised me to put 6sqmm SWA in the pipe under the ground and make it easy on whoever is doing the work. Did that, and the next guy I phoned was happy with how the cable was run and did the work for €570. I think the SWA was €60 for 20m.

So in the end, SWA in a pipe nearly 3 feet under the ground worked out well. Sparks is local and came back to replace a faulty breaker and seems reliable so now I've a local electrician for other things. He's coming back to do a periodic inspection report as my earth rod is old and not suitable. Good to have someone reliable and local to call on.

Thanks for the advice.

sealgaire

stiofan85 wrote: »

Thought I'd follow up:

Struggled to get a sparks in - most were reluctant when they asked about running cable along the wall to the back of the garden. The one quote I got was for €900 and I agreed to it, but then he vanished.

Spoke to a friend of a friend who's an electrician and he advised me to put 6sqmm SWA in the pipe under the ground and make it easy on whoever is doing the work. Did that, and the next guy I phoned was happy with how the cable was run and did the work for €570. I think the SWA was €60 for 20m.

So in the end, SWA in a pipe nearly 3 feet under the ground worked out well. Sparks is local and came back to replace a faulty breaker and seems reliable so now I've a local electrician for other things. He's coming back to do a periodic inspection report as my earth rod is old and not suitable. Good to have someone reliable and local to call on.

Thanks for the advice.

HI, was the 6mm enough? I'm doing the same, shed to run washing machine, dryer & a freezer. Don't know if its 6mm or 10mm i need.

stiofan85

sealgaire wrote: »

HI, was the 6mm enough? I'm doing the same, shed to run washing machine, dryer & a freezer. Don't know if its 6mm or 10mm i need.

6mm has since been checked by another sparks for a safety certificate and no problem. I'm moving house now and in the new one I asked for a 6mm to be run and electrician advised I only need 4mm. If I was doing it myself again I'd go for 6mm just to have the extra capacity

Bruthal

stiofan85 wrote: »

6mm has since been checked by another sparks for a safety certificate and no problem. I'm moving house now and in the new one I asked for a 6mm to be run and electrician advised I only need 4mm. If I was doing it myself again I'd go for 6mm just to have the extra capacity

Dont think id ever run a 4 square instead of 6.

stiofan85

Bruthal wrote: »

Dont think id ever run a 4 square instead of 6.

I asked about using 6sqm on here and was told to consult an REC to design the installation.

I asked an REC to design the installation and he said 4.

Bruthal

stiofan85 wrote: »

I asked about using 6sqm on here and was told to consult an REC to design the installation.

I asked an REC to design the installation and he said 4.

I just wouldnt run 4sq to a shed sub board. If I was ever involved in such matters again.

Maybe he had a load of it to use up.

stiofan85

Bruthal wrote: »

I just wouldnt run 4sq to a shed sub board. If I was ever involved in such matters again.

Maybe he had a load of it to use up.

In the new house it's only a light and a socket to charge a drill. Worst load would be circular saw. Don't think he intends on putting in a sub board afaik.

stiofan85

sealgaire wrote: »

HI, was the 6mm enough? I'm doing the same, shed to run washing machine, dryer & a freezer. Don't know if its 6mm or 10mm i need.

Last post may have been confusing - I asked the sparks in the new house about putting in 6sqm wiring to the shed with a light and socket, potentially to put in a washing machine down the line but most likely just a few power tools. He said 4 was enough. When I did the original shed I had a 6sqmm cable through the house already and I ran 6sqmm swa in a duct to match that and that seems to be the better move, per bruthal's point. It also gave me extra capacity down the line. I don't think there's a big price difference between the cables so go with the 6sqmm over the 4 for sure, but again I'm not an electrician and this is just my experience

Stoner

stiofan85 wrote:

Last post may have been confusing - I asked the sparks in the new house about putting in 6sqm wiring to the shed with a light and socket, potentially to put in a washing machine down the line but most likely just a few power tools. He said 4 was enough. When I did the original shed I had a 6sqmm cable through the house already and I ran 6sqmm swa in a duct to match that and that seems to be the better move, per bruthal's point. It also gave me extra capacity down the line. I don't think there's a big price difference between the cables so go with the 6sqmm over the 4 for sure, but again I'm not an electrician and this is just my experience

Look plenty of people have run these loads from a 2.5.sq

It depends on how many things are running at the same time and..

the most important thing here is the distance between the load and the consumer unit.

I imagine that is why the op was advise to speak to a rec so that run can be determined.

The longer the run the higher the voltage drop. You often need a significantly larger cable to run the same equipment if the shed is further away from the consumer unit.

6.sq is a more robust cable if you are running it outside.

Most kitchens have two number 2.5.sq cables to run dryers, dishwasher etc. The extra csa in the cable is to cater for the longer runs some might have to their sheds.