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Dertt

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Hi everyone.

Just built a man cave and am now adding electric to it.My proposal is;

swa on a 32amp mcb from my cu running out and being buried to the cave(25m run)

My cu is a TT arrangement on the earth.

I plan to bring 6mm swa into a cu in the cave.The maximum watts used at any one time would be approx 5000.

My question is do i use a 3 core swa(earthed from the first cu and then earthed again at the second with a TT arrangement or can i use 2 core and just earth at the cave with another TT arrangement.

There will not be any water pipes in the cave(timber)and there will only be relatively low wattage power tools, heater and led lighting.

I have messed with electrics from time to time but am not an expert on some matters.

Thanks.

 
Personally, i would use 2 core and just TT it at the shed end..

Ok, i know that 2 rods linked would give a lower Ra,......  BUT in my opinion at least, it would also mean that an earth fault that could potentially "liven up" all exposed conductive parts [and bits bonded to them] in ONE installation, would ALSO "liven up" the OTHER installation in the same way too.

Given the reliability of RCD's [not very] this is the last thing you want to happen...

[But that is just my opinion] Them that know better will be along soon!!

john...

 
Good point.when the electrian did the rewire on the house 20 years ago he put a spike into the ground so I was just assuming it was tt.

what is part p?

 
Part p is a building reg.. As you are running a cable out to a shed you are supposed to get building regs approval. This will be complicated and cost you more than getting an electricain to do the job for you. If it were me and you feel confident enough to do the job, i would forget about part P..

One MAJOR snag you have got though is you have not got the correct equipment to test the finished job to see that it is safe. "Working" and "safe" are two entirely different things....

john..

 
Ok.thats really helpful.didnt know about this site but it's an eye opener for the likes of me.thanks everyone so far.

 
assuming you are TT I would rod both ends and use 2 core SWA to shed. However, at some point you may wish to sell your house,in which case a Part P registration to building control and a cert for works will be needed. For that you need a registered electrician. Now, if you contact a few electricians and ask nicely, you may find one that is prepared to sign off works after you have done most of the work. I do this sometimes, but only if asked upfront. Ask me after the work has been done and I'll tell you to go away. This is because I like to supervise the work that people want my professional signature on to ensure it has been done properly. Under these circumstances, my preferred option is to allow customer to do all the donkey work like pulling in cables, and do all the finishing works - it saves you money, saves me doing the boring bit, but means I can sleep easy knowing the termination of sockets etc etc has been done to decent standard.

 
Yes,agreed on all fronts.i have been there before with certification.i was able to get a friend who was certified to check before covering up.i don't blame anyone who says er,"go away"when asked if they would certify it without seeing anything on the first and second fix!

 
Personally I think I'd check on the price of the cable, sometimes 3 core is cheaper that 2 core, if it is just buy 3 core and only use 2 cores.

 
Ok.thanks.i'll look around tomorrow.didnt know there was so much involved.not sounding boring but it's all quite interesting.

 
I was given a cu with an power rating of 100 amps rcd(brand new)

now I am running an armoured 6mm cable from the cu in the house off a 32amp mcb.the new cu in my man cave is also a split load 2 rcds with 63amp breakers on them.i will not be using more than 4000 watts at any one time.is this cu ok to use or should I get a smaller one before the spark comes around to test it.it was free though.bought from screwfix.

 
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