There are several safety related issues concerning plugging appliances either into double adapters, modern multiple extension sockets, or long extension leads. There are multi socket extension cables with room for up to 6 different appliances so it’s very easy to overload.
As long as their combined usage doesn’t exceed 13 Amps you can safely plug in and use up to 6 electrical products. However, it is very easy to overload these devices and many people don’t realise how easy. Overheating and eventually a risk of fire can be caused by as few as just 2 appliances if they use a lot of electricity – eg. washing machine and a kettle.
Using appliances with plug adaptors or multiple socket extension cables
A radio, phone charger, two lamps and a wireless router for example would potentially only add up to less than 3 amps. But you can dangerously overload an extension with just a washing machine and a microwave.
Extension cables with just one socket at the end
An extension cable with just one socket is preferable to a multi socket one. But it’s not ideal to plug a washing machine, dryer or dishwasher permanently into any extension cable because it introduces an extra risk of electrical overheating as well as extra potential bad connections.
Do not connect via an extension lead. Extension leads do not guarantee the required safety of the appliance (e.g. danger of overheating) ”
Many white goods appliances are plugged into extension cables. Anyone deciding to do so should at least use the right type of extension cable. You cannot use a 2 core extension cable which has no earth. If you do, although your machine will work, it is in a potentially lethal condition because it isn’t earthed – see I get electric shocks from the machine.
You must also ensure the cable is rated for 13 Amps. Many extensions have thinner cable than that of the washing machine.
This is an indication that the cable is meant for lawn mowers, lamps etc and not large white goods. If the cable is just as thick or thicker than that of your appliance then it should be 13 Amp and 3 core (with an earth lead).
Don’t assume anything though, check. Using a 5 or 10 Amp rated cable can cause overheating and is dangerous. Using cable that has no earth can kill if your appliance develops an insulation fault.
Don’t use wind up extension cables
Finally, note that extension cables that wind up must be fully unwound when in use. This type of extension cable will have two ratings written on it in amps. You will see that when wound up, or not fully unwound, the unit cannot take as many amps as when it is fully unwound.
For washing machines, dishwashers and tumble dryers (that can draw close to 11 amps) they would need to be fully unwound or they can get hot and overheat. In fact, many of these wind up extension reels are only rated for 10 Amps – so avoid. These cables are designed for temporary use.
Try to avoid extensions and adaptors
There is a dilemma regarding extension leads and adaptors. Firstly, they exist, and are sold in their millions. Therefore they must be safe. Yet it’s likely that any appliance user manual will advise that they are not to be used. This is a puzzling contradiction. If they are dangerous, they couldn’t be legally sold in the UK.
However, manufacturers know that an extension lead is a third party component added to their appliance which can develop faults which they have no control over. Many extension sockets are very cheap, and don’t seem to be made of high quality materials. Some extension cables can also be very long. Extending the length of an appliances mains cable is not ideal.
Do not connect the appliance by an extension lead, multi socket adaptor or similar. These can overheat and are a fire hazard ”
Don’t have extension socket on floor near washing machine
If you have a had a leak, it is not a good idea to have a live electric socket on the floor behind the washing machine or to the side. If you do have to use an extension socket, try to locate the socket somewhere where it couldn’t get wet.
So there we have it. However, as I said, if they are genuinely a fire hazard – how come they are happily sold in their millions – and in virtually every house in the country? The truth is they are an extra potential for something to overheat in high current appliances. If you can, always plug a washing machine, dishwasher, tumble dryer (or any appliance with a heating element inside) directly into a wall socket.
If this is impossible, and you have to use an adaptor or extension cable then use a good quality one. Use one as short as possible. Regularly check the plug where it plugs into the wall socket. Regularly check the individual sockets on the extension lead as well as the appliance’s plug. Look out for discolouring where it’s might be overheating and melting the plastic. Do not ignore anything like that.
Make your own extension cable
When I recently needed an extension cable for my oil filled radiator, I made one myself. You can see from the photo it is only as long as necessary. This would be the safest extension cable to use for a washing machine or other white goods appliance. I just made sure I used a good quality plug, a good quality extension socket, and three core mains cable.
This Amazon page shows a list of 13 amp high Impact Extension Double Sockets that you can add cable and plug to. Alternatively, look for extension leads with short cables, and has few sockets as you need. Try not to use a six gang socket just to plug a washing machine in for example.
Strange fishy smell near washing machine or when appliance is running?
Beware of a strange fishy smell coming from the kitchen or laundry room (unless you have some real fish in there of course).
We experienced such a puzzling smell for several days in our kitchen before I eventually tracked it down to electrical overheating in a plastic 13 amp plug.
A bad connection was causing sparking and burning and the plastic gave off this weird smell. I’m currently getting exactly the same smell when I turn a light on in a room at the back of my garage and I know it’s caused by melting plastic used in plugs, sockets, adaptors and light fittings.
If you get such a strange fishy smell near any of your appliances check the plugs and sockets for dangerous overheating.
Check if you are overloading a socket with this tool
The overload Socket Calculator is brought to you by Electrical Safety First.
How to work out how many amps your appliances use
If the Electrical Safety First tool above doesn’t help, or you want to make more accurate calculations you can work it out for yourself. It’s easy enough. You need to work out how many amps each appliance uses and make sure the combined total does not exceed 13 amps.
The amps an appliance uses can be worked out by dividing the wattage by the voltage (Amps = watts divided by voltage). In the UK the voltage is officially 230 volts (but in practice can be up to 240 volts). So a 1000 watt appliance divided by 240 (volts) is 4.16 amps. Do not go on what fuse the appliance takes, that is not how many amps it uses.
Electrical appliances have a rating plate showing how many watts it uses (see list below for help finding it). The photo above shows the rating plate of my toaster. It says it uses 780 – 930W. It’s unusual to show a range, but clearly we need to use the highest so we start with 930W (Watts). If we divide 930 by 240 (volts) we get 3.875. So the toaster uses 3.87 Amps.
My dishwasher’s rating plate (on the inside of the door) says it uses 1930W. So 1930 divided by 240 is 8.04. The dishwasher uses 8.04 Amps. The toaster and dishwasher running from the same socket would use 11.91 Amps. This is below the 13 Amp maximum.
Help finding appliance rating plates
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Hello Erica. I can see that one electrical safety site says “Don’t power microwaves using extension leads” but they don’t say why not, which is unsatisfactory. I don’t know of any reason why you can’t, other than as general advice it’s best to avoid extension leads on appliances that draw a lot of power as it introduces extra parts to potentially have a poor connection and overheat. For that reason alone if it’s not strictly necessary it’s best to avoid. To be honest I also find a lot of these extension leads don’t seem to be particularly well made.
Extension leads are designed to extend the reach of a 13 amp wall socket – that’s what they do. Unless it says in the extension lead’s instructions not to use with specific appliances I don’t see what the problem is.
If washing machines and tumble dryers can be plugged into extension leads, a microwave doesn’t use any more power and is often on for far less periods. If you need to use one make sure it’s a good quality one and as short as possible and rated 13 AMPs. To be sure I would try asking Electrical Safety First what the reason is behind their advice to not use one with a microwave.
The best way to use an extension socket in your case would be for someone who knows what they are doing to make up a short lead from 13 Amp cable, a plug and a single extension socket which can still be bought separately rather than a large overly long bought one with more sockets than you need.
Thanks, Andy. Will get one made up.
Hi Erica. Please note I’ve just spent some time working on my article. I’ve rephrased several things for the better and hopefully clarified a lot of things. I’ve also added a large new paragraph you should read called “Try to avoid extensions and adaptors”.
Hi. I have just purchased a single electric oven which I bought as it said it did not need installation as it was on 13amp plug. However the plug cable is too short and does not reach the plug socket on the wall. I have an extension lead for 13amp appliances and will only have the oven plugged in. Would this be safe as in the instructions it advises not to use extension cable. Please help
Hello Alexandra. In a perfect world you’d have the mains lead on the oven replaced with a longer one that reaches. But extension leads were invented to allow us to plug in things that would otherwise not reach. They can’t be intrinsically unsafe or they wouldn’t be around. However, manufacturers’ don’t like them and advise against using them.
Extension cables and leads are a source of potential problems and are likely to vary in quality. Their main concern is likely to be that an oven uses a lot of power, so if you used an extension socket and then plugged any other appliance in with it then it could cause an overload situation. The other concern is that it introduces extra connections at the extensions’s sockets that could cause overheating problems if they weren’t good quality and good connections.
Try to use an extension cable as short as possible. Consider getting the cable on the extension cut down to be just long enough to reach or try to buy one as short as possible or get one made up for you. They are by design usually quite long and you don’t want one that’s way too long. Finally keep an eye on it. Keep checking it to make sure the plug isn’t getting hot and starting to burn. Regularly unplug the oven from the extension and check the plug and socket and also check the extension cable’s plug and the wall socket.
So why don’t they make leads on appliances a lot longer? Some are hardly worth the bother so you have to use an extension lead…
Mains leads are as short as they think they can get away with because it’s cheaper. If they cut 1 inch off all their washing machines that can save them millions of inches of mains cable. It’s annoyingly the same with everything these days including my phone charging cable. Over the 40 years I’ve been in the appliance trade I reckon appliance mains cables have shrunk by a good couple of feet or more. They might have even halved if I think about it, but slowly over many years.
Hi, I have a fridge freezer and a chest freezer but only one socket, can I plug them both into a 13 amp extension lead?
Hello Julie. For some reason the overload calculator tool in my article doesn’t show fridges. Presumably because they vary too much in how much electricity they use. I would think they would OK but the only way to be sure is to work it out. I’ve added several new paragraphs to this article underneath the tool explaining how to work out how many amps your appliances use.
1 have a new double socket extension. When I have the small chest freezer on and then work tumble drier it fuses. Please explain why.
Hello Elis. A tumble dryer will use almost 12 amps. There’s not much left in a 13 amp socket. If the chest freezer uses more than a few amps it will overload the socket. I would assume that the combined amps that those two appliances use is greater than 13 amps.