How many watts can you pull safely from a wall socket?

Craterloads · 27 Dec 2013 at 23:11

As above, what's the safe amount you can pull from a single / double socket?

And correct me if I'm wrong but each floor will be on a ring so you could use that amount off each floor?

So if it's 2000w for example, you could pull 2000 watt on each ring / floor?

I know it's more than 2000 as my portable heater uses that much plus have my pc/tv in same room.

jamesfreddie · 27 Dec 2013 at 23:13

13A Per socket, so 13x240 = 3120 Watts.

Then what ever your MCB is that you have fitted in the ring is the maximum draw on all the sockets.

Fuzz · 27 Dec 2013 at 23:14

Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points.

Volts
Amps
Watts

240v
13 amps
3119.9 watts

itchy · 27 Dec 2013 at 23:16

Rule of thumb for safety no more than 3kw/3000watts.

Craterloads · 27 Dec 2013 at 23:17

Cheers, cutting it close then with 2000w heater plus everything else.

Amleto · 28 Dec 2013 at 00:36

that's peak power. You should probably stick to RMS for a/c power ~ 2200W

HardwareGeek · 28 Dec 2013 at 00:39

Double sockets are rated for 20A draw, over this long term will burn the socket out, so 2 x 13A long term and you might have problems.

In theory and 32A ring you can pull 230 x 32 = 7360 watts

Ps. Best to look at your fuse box and hope its labelled correctly for finding out if you have a ring for each floor, you could have one ring total for whole house, 1 ring for house and 1 for kitchen or each floor or wing / side of house separate or wired front and back all depends.

Normally you can get away with 1 ring for kit and 1 for house as tvs and other elecs dont use much

darael · 28 Dec 2013 at 00:40

As far as I know, 3000w per socket until you reach the ring's maximum allowance.

BaDBoY_uK · 28 Dec 2013 at 00:40

1.21GW

bitslice · 28 Dec 2013 at 00:52

HardwareGeek said:
Double sockets are rated for 20A draw, over this long term will burn the socket out, so 2 x 13A long term and you might have problems.

In theory and 32A ring you can pull 230 x 32 = 7360 watts

^^
Just confirming this as the only correct answer.

Single socket, 13A
Double socket, 20A (BS1353)

Ring main with breaker will supply a maximum of 32A via connected sockets.

Put the heater into a socket on its own, plug your PC's extension block into the other socket.

Amleto said:
that's peak power. You should probably stick to RMS for a/c power ~ 2200W

Not sure what you are looking at here?

Mains voltage is 240v RMS, you use that figure for calculating power.

/

stuie · 28 Dec 2013 at 18:44

Ive always worried about all this as to me having a 32amp ring main ran off 13amp cable seems like a recipe for disaster

grumpysculler · 28 Dec 2013 at 18:58

Fuzz said:
240v
13 amps
3119.9 watts

You should really use the EU standard of 230V (+10% -6%) for sums. Actual wall voltage is likely to be around 239V however (415 line voltage)

stuie said:
Ive always worried about all this as to me having a 32amp ring main ran off 13amp cable seems like a recipe for disaster

Who says the ring main is wired with 13A cable? The wiring regs don't. It's 2.5mm core stuff which is rated to about 27A. In normal operation, you have two of these in parallel so you could deliver about 54A (really a bit less) before melting cable.

Mynight · 28 Dec 2013 at 19:00

I was under the impression that a ring main is a single 2.5mm run in series between sockets :confused:

Fuzz · 28 Dec 2013 at 19:34

A ring main is exactly that. A cable comes out of the consumer unit goes to first socket, comes out of first socket onto the next socket, etc etc etec until you run out of sockets then the cable goes back to the consumer unit in a ring or circle.

Ha, just looked at my consumer unit and none of my circuits are rings, they are all radial

Something Else · 28 Dec 2013 at 21:29

Up to about 3000w you are fine.

Thats why on household items you won't find anything with more than a 13amp fuse or requiring more than 3000w of power.

Traffic_Warden · 28 Dec 2013 at 22:31

240v
240v
240v
240v
240v

:mad:

230v!!!!!!!

Jokester · 28 Dec 2013 at 22:35

UK mains voltage isn't normally 230v, when we harmonised with Europe all they did was make the tolerance big enough on the 230V spec to include our nominal 240V.

Fuzz · 28 Dec 2013 at 22:44

Traffic_Warden said:
240v
240v
240v
240v
240v

230v!!!!!!!

Shove it up your pooper.

Traffic_Warden · 28 Dec 2013 at 22:50

Jokester said:
UK mains voltage isn't normally 230v, when we harmonised with Europe all they did was make the tolerance big enough on the 230V spec to include our nominal 240V.

Yes but in the current wiring regulations, 230v is used for ALL calculations when it comes to cable selection etc.

240v is not used anymore in equations & calculations, at all. If it is being used, then it's not to the current wiring regulations at all.

Fuzz said:
Shove it up your pooper.

<snip>

230V _AC_

I never said you didn't have 240v coming out of your socket. I've seen 250v and 220v before... but 230v is for calculations....

Unicorn · 28 Dec 2013 at 23:27

240v AC is what comes out your socket and in the uk its at 50HZ freq (Well close as we can get it)

Could be certain when i did my 17th edition it was still down as 240v but i could be wrong.. Maybe thats my rule of thumb as usual.

@Mynight

Indeed. In theory it maybe should be done in parallel but iv never done it or seen anyone who has. 2.5mm T&E In series between cables and tbh most times iv seen this done especially on old builds it has just been.. A ring under the floorboards in the main hallways and tapping off into each room