Dummies guide to outside electrics

[trevorh]

Mr DIY (who managed to add a new kitchen ring main recently and now thinks he's an electrician) is looking to power a wooden garden shed, a wooden garden playhouse and my garage.

There are currently no electrics supplied to either. I am looking to add lights and power sockets to all three.

I am proposing add a spur with a 3a fuse to run the lights.

I have a spare slot on my main board, and am thinking (for safety sake) that I will get a 40amp MCB and run either 4.0 or 6.0mm cable to a new consumer unit housed in the garage (which is attached to the house, so I can run this cable under the floor from my main board and out of the air brick into the garage). The garage lights and power can be 'normal' 2.5 cable as it's all undercover, and then run some armoured cable down to the shed, and add another light and power socket, and then run the last bit of armoured cable to the playhouse for lights (and maybe a power socket).

Question is...is there anything wrong with this scenario, or have I missed anything?

If there is anyone out there that's going to comment/shoot me down, please can you do it in English!!!

T.I.A.

 

[mapj1]

Start work before january the 1st, and finish before April, or you will have to involve building control. (part P)
Basically your idea is sound, if the cable ratings are enough when you allow for voltage drop (depends on the lengths, and the likely loads you will be adding) ?You should ensure there is an RCD type breaker to cover any sockets that might power things outside, which is probably all of it, so it needs to be in the miniCU in the garage.

 

[trevorh]

Thanks for the reply.

As for the cable ratings and voltage drop, the shed / playhouse are approx 35 metres from the house.

I can't imagine anything more strenuous than the lights and lawnmower being used at the moment, but as the kids grow up and nag me more and more, then there may be a need for tv/playstation/satalite connections/pc/fridge/dvd player/heaters (and thats just for me!)...

 

[plugwash]

i generally idvise specifying for 40A

6mm is pushing it over 35m at that current so i would think its time for some 10mm SWA

 

[trevorh]

Also - how can I go about switching the CU in the garage off at night from the house, without sticking my head under the cupboard under the stairs every night? It's bad enough getting your shed broken into, without supplying the lights too! Would I need, for example, a cooker type switch in-between the house CU and the garage CU?

Thanks!

 

[andy]

Also - how can I go about switching the CU in the garage off at night from the house, without sticking my head under the cupboard under the stairs every night? It's bad enough getting your shed broken into, without supplying the lights too! Would I need, for example, a cooker type switch in-between the house CU and the garage CU?

Thanks!

yes, that would work

 

[ChrisRogers]

i neater idea would involve a contactor, and a keyswitch mounted in a conveniant location, or even a timer

 

[breezer]

I would advise against that. suppose you put an alarm on it, not a good idea to have it with no mains (yes i know they have battery back up) why not put the lights on a timer

 

[trevorh]

Thanks for your help - I'd better get started before the 1st Jan! Time to order the SWA cable.

Where do you all recommend I should buy from and are there any comments on brands of CU?

I've seen a few debates about certain brands out there. My house CU is Crabtree (it was already here when I moved in 2 years ago so don't start on me!!) - is this a decent enough brand?

Should I keep the new CU concurrent with this, or should I use a metal MK or Hager CU outside?

 

[plugwash]

generally its easier to terminate SWA into metal units and this is generally why i reccomend metal CUs for outbuilding wiring

also i think once you move to metalclad ALL brands get much tougher and less flimsy anyway.