Shed/workshop electrics

[Sloper]

I'll soon need to get my new 12x8 shed wired up, but haven't much of a clue about certain things and regulations, so I have some questions!

I've buried 18amp armoured-cable from the house to the shed (about 50ft) and will get a qualified spark to connect it all up. I want to buy as much, and do as much as poss myself though.

First, I need recommendations for a suitable CU - I want to run a 2kw convector heater, 3 or 4 4ft fluorescents and 2 or 3 twin plug-sockets. I may also want to install security lighting on the outside, and possibly at a later date, run power from here to my other shed, just for lighting and a cheap PIR-type alarm.

Would the armoured-cable be best passed through the floor of the shed and connected to the CU inside, or would it terminate in a some sort of box attached to the shed outside?

Also, what type of cable would I use between the house CU and the armoured cable (3 or 4 yds), which I presume will be connected via box on the wall where it enters the house.

Can anyone recommend an electrician in Tameside (east Manchester)?

Also, where can I learn about CUs and relevant terminology (MCBs RCDs etc)?
Sorry for all the questions.

Thanks for any advice.

 

[ChrisRogers]

by 18amp i guess you mean 1.5mm2 SWA?

This is a wee bit too small for the job idealy. What sort of load will those sockets be supplying? And i presume by security lights you mean 500w halogen lights?......

 

[plugwash]

unfortunately current rating isn't the only consideration when sizing cables but diy sheds don't tell you that

is the csa marked on the cable (i suspect its 1.5mm but i could be wrong if its xple or similar)

50 feet is a bit under 20 meters so by my calculations 1.5mm should be just about ok for a 16A cuircuit over that distance

most sparkys would rather not complete someone elses work so i would talk to your sparky before you start doing anything further. also your heater plus a socket

have you filled the trench yet? if not then i would definately lift that cable and put something bigger in (6mm or so should be ok) you don't want to be digging it up again to put more stuff down there

i would always enter wooden outbuildings through the floor as this prevents water entry through the hole

 

[Sloper]

I bought and buried the cable under a patio I layed 2 years ago. I can't remember what it was now... but my wife agrees that 18amp rings a bell? Sorry I can't be specific. I do remember that it was the heavier duty of two types that B&Q supplied.

Sockets will only be for items like a soldering iron, lamps, motorcycle battery charger etc.


Just been out to check the SWA... its 3x2.5mm2 BS5467 600/1000V .

 

[ryanj]

2.5mm^2 SWA is good for 30+amps.

 

[ban-all-sheds]

Not if it's PVC.

And not either type over a distance of 20m.....

 

[alertelec]

But at least it sounds like your cable will be adequate for supplying your new shed. A rough tott up looks like you have a requirement of about 3kw/16a. Thats pretty near the max so you shouldn't consider supplying another shed in the future.

I'm not a sparks so I can't advise on termination but suffice to say, if it was my house I'd get a sparks in at this stage anyway. It'll save you wasting money on the wrong materials. The little things like termination are the tricks of the trade which the sparky learns the hard way through experience handed down over the years. You may be able to buy the correct materials if you are lucky and ask enough questions, but you won't know the correct way of installing it. The major part of the job, laying the armoured is already done anyway.

 

[ban-all-sheds]

But at least it sounds like your cable will be adequate for supplying your new shed. A rough tott up looks like you have a requirement of about 3kw/16a.

Haha! - it's my turn! 3kW is 13A. Face is regained

 

[Sloper]

I agree Alec, that its time to get an electrician in.

Meanwhile though, I'd like to know how a CU that is recommended as a 'garage CU' differ from a normal house one? Can some tell me what features I should look for in one?

Cheers all

 

[plugwash]

the CUs sold as garage CUs seem to generally be waterprrof types also they generally only have a couple of ways and are generally rcd units


personally i would advise against them because they are plastic which means you are relygin on the banjo for earthing (where as with a metal box you have earth continuity through the box as well ) and also i personally would rather have the rcd at the house end (although this is a heavilly disputed topic)

what i would do given your cable size is go from a 20A breaker in the non-rcd side of the CU to a metal 2 module box with a seperate rcd (best not to put otubuilding power on the house rcd) and then fit a small metalclad switch only CU in the shed but every sparky will have thier own preferences for how to do it so if you are getting a sparky in let them supply or at least specify the kit.

 

[Sloper]

Yep. I'll leave the rest to a spark now.

Well, thanks to all for the replies.