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. 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. dishwasher and 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. Washing machines, tumble dryers and dishwashers all use so much electricity that they should never be used together on the same wall socket. They usually use between 10 and 13 amps.
Is it OK to use an extension cable 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. Miele for example say in their washing machine instruction book –
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.
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 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.
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.
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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. Neither is adding extra electrical connections between the appliance plug and the wall socket. Here is what my Miele tumble dryer user manual says on the subject –
Do not connect the appliance by an extension lead, multi socket adaptor or similar. These can overheat and are a fire hazard. ”
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.
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.
Very informative, and useful…a simple article like this will save lives.
Is it OK to use extension cables with just one socket at the end to plug a multi-socket lead into if all that’s in the multi-socket lead is a phone charger and a handheld console charger?
The longer a cable ends up, and the more plugs and sockets it has the more there is to go wrong including things overheating due to poor connections. The products you mention don’t use much power at all though so it shouldn’t be overloaded.
Can I safely plug in a landline and fire into an extension socket, or does fire need to be connected via a wall socket. Thanks
Hello Patricia. Ideally a fire should be plugged directly into a wall socket as extension sockets increase the possibility of overheating but if plugged in to a good quality extension it should be ok.
Hi Can I safely plug in a 55 inc. TV, Sky HD box, Sky wireless hub, a Cinema surround system and a Amazon box into a multi socket lead.
Best regards
Brian Gibson
Hello Brian. The main rule of thumb is not to exceed 13 amps. Although it sounds like you would be plugging a lot of things in, none of the items are likely to draw a lot of current so even when combined they may use much less electricity than a single electric fire. The way to check is to look at each appliance’s rating plate which should tell you how many amps it draws, then add them all together to see if they add up to more than 13 Amps.
I’ve just reinstated a very handy overload checking tool provided by electrical safety first (Electrical safety Council). I originally had this tool as part of my article but it went faulty so I removed it. It appears to be working okay at the moment and you can find it at the bottom of the article now.
I’m trying to connect a washing machine and getting no power. First I plugged it into the extension cable that the old machine was connected to. When that didn’t work, I connected it to a standard fixed socket in the wall just to check. Again no power.
The new washing machine has a 10 amp plug while the old one had a 13amp. Could that be the problem and can it be safely cured by putting a 13 amp fuse into the washing machine plug?
Hello Robert. A washing machine needs a 13 amp fuse. A 10 amp fuse is likely to blow. Not immediately, only when the washing machine is heating up the water.
Personally, I would fit anything that draws a lot of power with a 13 amp fuse; TV, washing machine, tumble dryer, anything like that. Also, once you’ve replaced the fuse, get in touch with the manufacturer of your machine to point out their error (or the seller if it’s a refurb).