Temporary Shed Electrics

[JamesB]

Hi.

I've a need to run a 3KW boiler in my shed (possibly with a light as well). I think 3kW is cutting it a bit close for a standard extension lead. I'm also unable (rented house) to install a proper electical connection to the shed.

I'll only need it for a few hours a month. I was wondering if I could convert a 2 gang house socket to supply the ~14/15A needed and run this to the shed (albeit temporarily) with IEC308 connectors - via an RCD of course? I'm also not happy about taking it off a spur. I do have an upstairs ring which is hardly used.

I'm also not going to take any suggestions of using two mains plugs to a junction box.

Any ideas?

Thanks,

[TMC]

3kw is approx 12.5 amps at 240 volts therefore a good quality extension lead (that is one which will carry 13 amps load when fully unwound would be adequate) If you want to give a bit of a load margin get a 16 amp caravan lead from any caravan or camping shop and buy an adapter lead with a 13 amp plug on one end and a 16 amp blue socket on the other and plug into a 13 amp socket

here is an example

you terminate in the shed is another matter

If it was just the boiler I would connect a 16 amp plug to it

I have however connected a socket bar to a 16 amp cable and then used correctly fused plugs for different appliances but I would not do this with the boiler load being so high

As it is all temporary I would run a second standard lead for other use

Tony

[JamesB]

But we're on ~230V which is 13.05 amps.

If I'm trying to run a light as well, that's about another few mA.

I ask, because I know someone with the same boiler. Every month she's got to replace the mains plugs because of heat damage to them - the sockets occasionally need replacing too.

[dom]

Have you got an unused 16A MCB in your consumer unit? Or a 16A radial that isn't needed that you could disconnect e.g. immersion heater?

Then fit a commando socket to that dedicated radial.

(assuming you're disregarding part P, and your tenancy agreement)

[Roger Mills]

> How you terminate in the shed is another matter

Something like

or would almost do - except that they both have 10A circuit breakers.

I wonder whether either has an industry standard circuit breaker which could be replaced by one with a higher current rating? The whole thing would still be protected by the 13A fuse at the house end, of course.

[JamesB]

There is an 3kW immersion heater that isn't being used, however I'm not entirely convinced that it's wired correctly - it doesn't look hefty enough for it.

No unused circuits in the consumer unit unfortunately - I'm also not allowed to play with that.

Landlord is fine with me changing sockets, etc as needed. I'm not going to play with anything part P covers.

[dom]

You mean the flex (from the switch to the cylinder) or the fixed wiring from the CU?

If the fixed wiring is good, change to a commando socket here. If not, unhooking it from the CU would be wise anyway - then fit the commando socket there.

[TMC]

It appears then that you real problem is how to supply at the house end

I have had over the years many appliances that use 3kw (Kettles fat fryers compressors twin tub washing machines electric fires etc) With good quality plugs and sockets although they get a bit warm I have never had to replace any

As others have said anything other than plugging in to an existing socket will contravene your tenancy agreement

However if the boiler came fitted with a 13 amp plug it is rated to work from a 13 amp socket and should cause no problems

Tony

[JamesB]

Both. It's just standard round cable coming from somewhere in the loft, via a switch to the cylinder. Not sure where it's wired into.

I think I'll try a normal 13A plug to a 16A commando for the time being. If I have trouble with heat, etc I'll think again and maybe pay to get a new circuit in the CU.

Thanks for the advice people.

[John Rumm]

You will probably find that the actual rating is 3kW at 240V, and so it will only draw about 12A at 230V.

A case of needing good quality accessories.

[John Rumm]

Remember part P encourages temporary lash ups in preference to safe permanent wiring!

[Andy Dingley]

Lidl are currently selling extension cables, of excellent quality. Big conductors, nice robust rubber insulation. 25m for 15 quid

[dom]

Yes, I've seen on test how MK hardware offers *consistently* very low contact resistance, and others may or may not.

[dennis]

Some 2.5 mm2 arctic flex should do fine. Its no more than a kettle. If you are still worried run another cheap one for the lights.

[dennis]

My temporary lash up is in 2.5 mm T&E and would pass the regs if it wasn't a temporary lash up.

[Andrew Gabriel]

Guideline for 13A extension lead cable size...

Use 1.25mm^2 for up to 12m Use 1.5mm^2 for up to 15m Use 2.5mm^2 for up to 25m [notice the pattern?]

(You probably won't fit 2.5mm^2 into a standard 13A plug.)

[George (dicegeorge)]

what is MK hardware?

Milton Keynes?

[Owain]