How many watts maximum can we use in a UK wall socket?

josh115

josh115

josh115

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Hi, how many watts can we safely use in a single socket UK wall outlet?

Does it make a difference if we have a double wall socket? (does that mean we can use double the amount of watts?)

Is the maximum amount of power we are able to use calculated per socket or is that for the whole floor? (i think we have two electrical rings in UK homes, one upstairs and one downstairs, is that right?)

Thanks
 
As you asked how much can be used safely, the answer is that it depends on how well made the socket and the plug are.

You are supposed to be able to draw roughly 3kW from a single socket; but if there's any play in the way the socket grips the pins or if the plug is undersized you can get dangerous levels of heat if
it is used for an extended period.

Some people are finding out the hard way that cheaping out on sockets isn't a good idea when charging their electric cars from a domestic socket (and that extension lead ratings are mostly bogus).

You are right that commonly UK homes have two mains socket rings (with kitchens quite often being separate again). In that design the maximum for the ring would be 32A (so about 7.5kW).
You are not expected to draw the maximum power from every single socket on the ring. As for pulling the maximum from both sockets in a double - that'll just expose any weaknesses
in the quality of the socket all the more quickly.

That is not the only way that UK houses may be wired, particularly if older. And there's no guarantee that a particular socket isn't on a spur. Although if done right a socket on a spur should be
a single and can still draw the full 13A.

In short, yes you can plug in a 3 bar electric fire for a few hours without a problem, but if you are going to be drawing large amounts of power for an extended period of time get whatever it
is installed properly.
 
VersionMonkey said:
As you asked how much can be used safely, the answer is that it depends on how well made the socket and the plug are.

You are supposed to be able to draw roughly 3kW from a single socket; but if there's any play in the way the socket grips the pins or if the plug is undersized you can get dangerous levels of heat if
it is used for an extended period.

Some people are finding out the hard way that cheaping out on sockets isn't a good idea when charging their electric cars from a domestic socket (and that extension lead ratings are mostly bogus).

You are right that commonly UK homes have two mains socket rings (with kitchens quite often being separate again). In that design the maximum for the ring would be 32A (so about 7.5kW).
You are not expected to draw the maximum power from every single socket on the ring. As for pulling the maximum from both sockets in a double - that'll just expose any weaknesses
in the quality of the socket all the more quickly.

That is not the only way that UK houses may be wired, particularly if older. And there's no guarantee that a particular socket isn't on a spur. Although if done right a socket on a spur should be
a single and can still draw the full 13A.

In short, yes you can plug in a 3 bar electric fire for a few hours without a problem, but if you are going to be drawing large amounts of power for an extended period of time get whatever it
is installed properly.
Click to expand...

Thanks, i didnt think of this, i have fairly old sockets in that room, so maybe i should upgrade them. Are there any types of sockets you'd recommend? Also im ok to install a wall socket myself aren't i, without the need for a qualified electrician? (as long as i turn off the electricity before hand etc)

would something like this:

https://www.amazon.co.uk/Energenie-...csubtag=06-3663653-11-0000000&geniuslink=true

Help warn me if there are dangerous levels of heat coming from the socket as you mentioned?

So basically, 7.5k is the TOTAL amount of appliances that should be connected for the WHOLE ring. Which means, all the appliances connected in every room should total less than 7.5k watts. Would i then need to workout how much i have connected upstairs in my house to stay under 7.5k W in total?

I will be connecting a ASICS miner, which will be running 24/7. it draws about 235 watts on power connected to a 750 watt gold rated PSU. Actually i was intending to run two Asics miners from this PSU eventually, but would just be starting out with one. When you say get it installed properly, what do you mean by this?

Thanks
 
josh115 said:
Thanks, i didnt think of this, i have fairly old sockets in that room, so maybe i should upgrade them. Are there any types of sockets you'd recommend? Also im ok to install a wall socket myself aren't i, without the need for a qualified electrician? (as long as i turn off the electricity before hand etc)

would something like this:

https://www.amazon.co.uk/Energenie-...csubtag=06-3663653-11-0000000&geniuslink=true

Help warn me if there are dangerous levels of heat coming from the socket as you mentioned?

So basically, 7.5k is the TOTAL amount of appliances that should be connected for the WHOLE ring. Which means, all the appliances connected in every room should total less than 7.5k watts. Would i then need to workout how much i have connected upstairs in my house to stay under 7.5k W in total?

I will be connecting a ASICS miner, which will be running 24/7. it draws about 235 watts on power connected to a 750 watt gold rated PSU. Actually i was intending to run two Asics miners from this PSU eventually, but would just be starting out with one. When you say get it installed properly, what do you mean by this?

Thanks
Click to expand...

Regarding brands of sockets, a quick search would suggest MK are still OK, with recommendations for Crabtree, Hamilton and Schneider Electric. Under the regs you are permitted to replace fittings yourself without having to do the Part-P notification.

I'd avoid that particular power meter, judging by a couple of the review photos.

But it doesn't sound like you are planning to draw anywhere near dangerous levels. That 235W rating is about 1A, so is a fraction of the maximum; even running two should still be OK (from the point of view of the socket/plug, at least).

Problems only start when you get up around the 10A+ mark - so around ten times what you are proposing using. Poorly made sockets may not grip the pins of the plug properly, meaning there's only a small contact area; which causes
a heat build up when a large current flows over it. There are also some badly made plugs that have too-small pins or even a loose fuse holder that can have the same effect. Generally, though, such problems only show up when used at
that level for extended periods of time (like charging an electric vehicle for 8 hours at a time).

But like I said, if you stick to the levels you are suggesting you won't have a problem. A power meter would give you some reassurance about the amount of power you are drawing, but that 750W PSU is likely to go bang before you could
draw too much power from even an old socket. A power meter won't tell you about heat, but if everything is as it should be then neither the plug nor the socket should get warm to the touch when in use (wall warts being a different matter as it's the transformer
that's getting hot rather than the pins (hopefully)).

My reference to getting it installed properly was to suggest that if you were planning to draw up to the maximum on multiple sockets, a safer approach would be to get an electrician to install a dedicated circuit with the equipment appropriately wired in. But it doesn't sound like you are.

The 32A/7.5kW for a typical domestic ring main would be the maximum for all appliances turned on at the same time. It's unlikely you'll get close unless you are using several convector/fan heaters (in which case you'll get very warm unless your house is very big (and then you'll probably have multiple rings; not just upstairs/downstairs)).
 
VersionMonkey said:
Regarding brands of sockets, a quick search would suggest MK are still OK, with recommendations for Crabtree, Hamilton and Schneider Electric. Under the regs you are permitted to replace fittings yourself without having to do the Part-P notification.

I'd avoid that particular power meter, judging by a couple of the review photos.

But it doesn't sound like you are planning to draw anywhere near dangerous levels. That 235W rating is about 1A, so is a fraction of the maximum; even running two should still be OK (from the point of view of the socket/plug, at least).

Problems only start when you get up around the 10A+ mark - so around ten times what you are proposing using. Poorly made sockets may not grip the pins of the plug properly, meaning there's only a small contact area; which causes
a heat build up when a large current flows over it. There are also some badly made plugs that have too-small pins or even a loose fuse holder that can have the same effect. Generally, though, such problems only show up when used at
that level for extended periods of time (like charging an electric vehicle for 8 hours at a time).

But like I said, if you stick to the levels you are suggesting you won't have a problem. A power meter would give you some reassurance about the amount of power you are drawing, but that 750W PSU is likely to go bang before you could
draw too much power from even an old socket. A power meter won't tell you about heat, but if everything is as it should be then neither the plug nor the socket should get warm to the touch when in use (wall warts being a different matter as it's the transformer
that's getting hot rather than the pins (hopefully)).

My reference to getting it installed properly was to suggest that if you were planning to draw up to the maximum on multiple sockets, a safer approach would be to get an electrician to install a dedicated circuit with the equipment appropriately wired in. But it doesn't sound like you are.

The 32A/7.5kW for a typical domestic ring main would be the maximum for all appliances turned on at the same time. It's unlikely you'll get close unless you are using several convector/fan heaters (in which case you'll get very warm unless your house is very big (and then you'll probably have multiple rings; not just upstairs/downstairs)).
Click to expand...


Thanks for that mate, puts my mind at ease. I guess i will cross the road of an electrician if i need to in the future. But just for reference, would it be expensive to hire someone to install a dedicated ring, how much am i looking to get something like that fitted?

I'll look for a better power metre also, it was just the one they recommended from the above link posted by inogen.

Also ill probably replace the sockets with some of the ones you suggested just to be on the safe side.
 
Quality of sockets wont make any difference if the ring they are on isn't up to scratch.

If you have a modern consumer unit is present with RCBO's and SPD's then you can be assured that to install one of these, you'd have had proper tests on the wiring up to 500V which highlights any issues with the wiring before they install a modern consumer unit.

Modern consumer units and associated RCBO's are so sensitive that if any faults are present they will trip instantly - hence the test electricians do before installing them.
 
MagicBoy said:
Someone skipped science at school.

240V * 13A = 3120W.

Theoretically.
Click to expand...

I believe I used terms like "roughly" and "about". As @james.miller already pointed out It's A Bit More Complicated Than That.

josh115 said:
Thanks for that mate, puts my mind at ease. I guess i will cross the road of an electrician if i need to in the future. But just for reference, would it be expensive to hire someone to install a dedicated ring, how much am i looking to get something like that fitted?

I'll look for a better power metre also, it was just the one they recommended from the above link posted by inogen.

Also ill probably replace the sockets with some of the ones you suggested just to be on the safe side.
Click to expand...

Cost of a separate circuit depends on where you are in the country and what's already there and exactly how you want the new circuit arranging.

Use the power meter to get an idea of the actual current draw of the equipment and then plug the equipment in directly to a socket.

With the load you are talking about you are unlikely to have a problem with the sockets unless they are obviously worn.

A cautious approach would be: Inspect the plug - make sure the pins are a normal size and that the fuse is properly in the holder and gripped well.
Inspect the socket - make sure there is no damage to the exterior and when you put the plug in it should stay in firmly with no movement.
Run the miner for 8-10 hours (not overnight, do it while you are awake and in the house) and check if the plug or socket feel hot to the touch immediately afterwards.
If normal then let it run but periodically inspect both plug and socket for signs of damage.
 
Woodsta888 said:
Quality of sockets wont make any difference if the ring they are on isn't up to scratch.

If you have a modern consumer unit is present with RCBO's and SPD's then you can be assured that to install one of these, you'd have had proper tests on the wiring up to 500V which highlights any issues with the wiring before they install a modern consumer unit.

Modern consumer units and associated RCBO's are so sensitive that if any faults are present they will trip instantly - hence the test electricians do before installing them.
Click to expand...

True, but this:

https://www.speakev.com/threads/near-miss-charging-from-a-13a-household-socket.139542/

is an example of what I was cautioning against as the OP was asking about the maximum current draw from a socket. That example was probably down to a dodgy extension lead, but examples of socket failure are also out there (and wouldn't necessarily trip an MCB,).

Fortunately it sounds like the OP isn't planning on running a full-on mining farm from a single multi-way adapter; so they should be OK. Unless their house is 100 years old and still has the original wiring...
 
VersionMonkey said:
True, but this:

https://www.speakev.com/threads/near-miss-charging-from-a-13a-household-socket.139542/

is an example of what I was cautioning against as the OP was asking about the maximum current draw from a socket. That example was probably down to a dodgy extension lead, but examples of socket failure are also out there (and wouldn't necessarily trip an MCB,).

Fortunately it sounds like the OP isn't planning on running a full-on mining farm from a single multi-way adapter; so they should be OK. Unless their house is 100 years old and still has the original wiring...
Click to expand...


I wasn't trying to take anything away from what you said at all.

I was just affirming that the OP could look at his consumer unit and depending on the type, could assess how old his wiring was and whether to be cautious on whether to take a socket draw to the max. Modern unit will mean house has been tested before and after installation.

Though that link you posted does show a house that's only 2 years old! Dunno if that was the plug or socket that went in that pic.
 
Thanks everyone, sorry for the late reply

Woodsta888 said:
Quality of sockets wont make any difference if the ring they are on isn't up to scratch.

If you have a modern consumer unit is present with RCBO's and SPD's then you can be assured that to install one of these, you'd have had proper tests on the wiring up to 500V which highlights any issues with the wiring before they install a modern consumer unit.

Modern consumer units and associated RCBO's are so sensitive that if any faults are present they will trip instantly - hence the test electricians do before installing them.
Click to expand...

Thanks, how do i know if my unit is present with RCBO'S and SPD'S? I had a look at my consumer unit and its a Crabtree type SB6000, Says 63A RCCB, 30 mA trip. Is that good?
 
VersionMonkey said:
I believe I used terms like "roughly" and "about". As @james.miller already pointed out It's A Bit More Complicated Than That.



Cost of a separate circuit depends on where you are in the country and what's already there and exactly how you want the new circuit arranging.

Use the power meter to get an idea of the actual current draw of the equipment and then plug the equipment in directly to a socket.

With the load you are talking about you are unlikely to have a problem with the sockets unless they are obviously worn.

A cautious approach would be: Inspect the plug - make sure the pins are a normal size and that the fuse is properly in the holder and gripped well.
Inspect the socket - make sure there is no damage to the exterior and when you put the plug in it should stay in firmly with no movement.
Run the miner for 8-10 hours (not overnight, do it while you are awake and in the house) and check if the plug or socket feel hot to the touch immediately afterwards.
If normal then let it run but periodically inspect both plug and socket for signs of damage.
Click to expand...

Thanks mate, good idea about running it during the day to test it out, will definitely do that first. I'll also inspect the plugs but i may just change them anyway because they are definitely old in comparison to the ones we have around the rest of the house

Just for reference, is there any reason why i can't install a double wall socket into where there are single wall sockets in that room?
 
Last edited:
josh115 said:
Just for reference, is there any reason why i can't install a double wall socket into where there are single wall sockets in that room?
Click to expand...

Yes. If the socket is on a spur (i.e. fed by a single cable) rather than part of the ring then it should stay as a single. If you are thinking of changing things around (instead of just swapping like-for-like), it might be worth asking on a DIY or electrician's forum once you've checked out how things are connected to be sure you've got every eventuality covered.
 
VersionMonkey said:
Yes. If the socket is on a spur (i.e. fed by a single cable) rather than part of the ring then it should stay as a single. If you are thinking of changing things around (instead of just swapping like-for-like), it might be worth asking on a DIY or electrician's forum once you've checked out how things are connected to be sure you've got every eventuality covered.
Click to expand...

Thanks mate, ill see what i can find out there
 
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