Whitegoods Help article

Extension sockets and adapters

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Quick Answer

If an extension lead must be used, it must be 3-core (with an earth wire), rated for at least 13 amps, fully unwound if it is a reel type, and positioned where it cannot get wet. Never use two large appliances on the same extension or multi-socket adapter – the combined current draw can exceed 13 amps and cause overheating.

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Large appliances should be plugged directly into a wall socket

Washing machines, tumble dryers, and dishwashers draw close to 10 to 13 amps and should be connected directly to a dedicated wall socket wherever possible. Extension leads and multi-socket adapters introduce additional connection points that can overheat, and most manufacturer instruction books specifically advise against their use with large appliances.

Extension leads and multi-socket adapters are used in virtually every home, and sold in their millions. They are legal products and can be used safely. The issue with large white goods appliances is specific: the current they draw, combined with the extra connection points and potentially lower-rated cable of an extension lead, creates a genuine overheating risk that a direct wall socket connection does not.

Why Large Appliances Are Different

The problem is not that extension leads are inherently dangerous – it is that they are frequently used with appliances drawing far more current than the lead was designed for, or in combinations that exceed the 13-amp limit of a standard UK wall socket.

Appliance type Approximate current draw Extension lead risk
Washing machine 10 to 13 amps High – near the maximum for a single socket
Tumble dryer 10 to 13 amps High – never combine with any other large appliance
Dishwasher 8 to 10 amps High – leave little headroom for any other device
Microwave 4 to 7 amps Medium – dangerous if combined with any large appliance
Kettle 8 to 13 amps High – never combine with a washing machine or dryer
Phone charger, lamp, router Under 1 amp each Low – safe to combine on a multi-socket extension

A washing machine and a kettle running simultaneously on the same extension or socket will exceed 13 amps and cause overheating. A radio, two lamps, and a phone charger combined will draw less than 3 amps – well within any extension lead’s capacity.

“Do not connect via an extension lead. Extension leads do not guarantee the required safety of the appliance (e.g. danger of overheating).”

Miele washing machine instruction manual

“Do not connect the appliance by an extension lead, multi socket adaptor or similar. These can overheat and are a fire hazard.”

Miele tumble dryer instruction manual

If an Extension Lead Must Be Used: The Requirements

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Must be 3-core with an earth wire

A 2-core extension lead has no earth. Using a large appliance without an earth connection puts the user at risk of electric shock if the appliance develops an insulation fault. See our guide on electric shocks from washing machines for more on why earthing matters.

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Must be rated for 13 amps

Many extension leads use thinner cable than the appliance’s own flex, rated for 5 or 10 amps. If the cable is noticeably thinner than the appliance’s cable, it is not suitable. A 10-amp rated extension used with a washing machine drawing 13 amps will overheat.

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As short as possible

Longer cable means more resistance and more heat generated. Use the shortest extension that achieves the connection needed. Do not coil unused cable – lay it out fully.

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Not positioned where it could get wet

If the washing machine leaks, a live extension socket on the floor behind or beside it becomes extremely dangerous. Position any extension socket at worktop height or somewhere it cannot be reached by water from a leak or overflow.

Reel-Type Extension Cables: A Specific Danger

Extension cables on a reel must be fully unwound before use. Wound cable acts as an inductor – it generates heat when current flows through it. All reel-type extensions have two current ratings printed on the body: one for fully unwound and a lower rating for wound or partially wound. The wound rating is typically around 10 amps – which is insufficient for a washing machine, dryer, or dishwasher drawing up to 13 amps.

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Reel extensions are designed for temporary use only

Do not use a reel-type extension lead as a permanent connection for a large appliance. Even when fully unwound, many reel extensions are only rated for 10 amps – below the requirement for a washing machine or dryer. Avoid them for white goods entirely where possible.

How to Calculate Whether You Are Overloading a Socket

The 13-amp limit applies to the total current draw of everything connected to a single socket or extension. You can check your own combination using the formula below.

Formula

Amps = Watts ÷ Voltage. In the UK, use 240 volts for this calculation. Do not use the fuse rating of the appliance as its amp draw – these are different figures.

The wattage of each appliance is on its rating plate – usually found on the back of the machine, inside the door, or on the underside. As an example: a dishwasher rated at 1930W draws 1930 ÷ 240 = 8.04 amps. A toaster rated at 930W draws 930 ÷ 240 = 3.87 amps. Combined, those two appliances draw 11.91 amps – within the 13-amp limit. Adding a washing machine drawing 10+ amps would take the total well over the limit.

The Socket Overload Calculator from Electrical Safety First can help with this calculation if you prefer not to do it manually.

For help finding the rating plate or model number on specific appliance types, see our guides on how to find an appliance model number and where to find the model number on a fridge or freezer.

The Warning Sign: A Fishy Smell Near Appliances

A strange fishy or burning plastic smell near an appliance, plug, or socket that has no other obvious explanation is a warning sign of electrical overheating. Burning or arcing in plastic components – plugs, sockets, adapters, and extension leads – can produce this distinctive smell before any visible damage appears.

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If you smell burning plastic near an appliance or socket

Unplug the appliance and inspect the plug, socket, and any extension lead for discolouration, melting, or scorch marks. A discoloured plug or socket face indicates overheating that must be investigated before the appliance is used again. Do not ignore this warning sign.


Frequently Asked Questions

Can I plug a washing machine into an extension lead?

Ideally not – manufacturers including Miele explicitly advise against it in their instruction manuals. If it is unavoidable, the extension must be 3-core with an earth wire, rated for at least 13 amps, as short as possible, fully unwound if it is a reel type, and positioned where it cannot get wet. Never use the washing machine and another large appliance on the same extension.

Can I plug two large appliances into the same extension lead?

Not if either is a washing machine, tumble dryer, or dishwasher. These appliances draw 10 to 13 amps individually – two together would exceed the 13-amp maximum of a standard UK socket and cause the extension lead to overheat. Even two moderate appliances – a washing machine and a microwave or kettle – can exceed this limit.

How do I know if my extension lead is rated for 13 amps?

Check the rating printed on the body of the extension lead or on the plug. If the cable appears noticeably thinner than the appliance’s own flex, it is likely rated below 13 amps. Do not guess – only use an extension if you can confirm it is rated for 13 amps and has a 3-pin plug with an earth pin.

Does a reel extension lead need to be fully unwound?

Yes, always. Wound cable generates heat when current flows through it. Reel-type extension leads have two amp ratings – one for fully unwound and a lower one for wound or partially wound. The wound rating is typically around 10 amps, which is insufficient for a washing machine or dryer. Always fully unwind a reel extension before use and avoid this type for permanent large appliance connections.

What does a fishy smell near a plug or socket mean?

A fishy or burning plastic smell near an appliance, plug, socket, or extension lead that has no other explanation is a warning sign of electrical overheating. Unplug the appliance and inspect all connections for discolouration, melting, or scorch marks. Do not use the appliance or socket again until the cause has been identified and made safe.

Last reviewed: April 2026.

Discussion

77 Comments

Grouped into 51 comment threads.

Francis 3 replies Hello again, Does 3 way and 3 core mean the same thing? And also what's a 4 way strip? Is that ok to use in an extension? F

Hello again,

Does 3 way and 3 core mean the same thing? And also what’s a 4 way strip? Is that ok to use in an extension?

F

Andy Trigg (Whitegoodshelp)

Likely replying to Francis

Hello Francis. Three way usually refers to 1 of those square adapters that you plug into a socket. They commonly have three sockets. Three core means that the cable has got three cores running through it, live, neutral, and earth. It is vital that any extension cable that is to be used for a white goods appliance is not only three core, but 13 amp. I 13 amp cable is usually fairly thick. A four-way strip is presumably just an extension cable with four sockets at the end.

Justyna Litwin Martinelli

Likely replying to Andy Trigg (Whitegoodshelp)

Hi Andy, your Website is very helpful:) thanks for sharing your knowledge.
I’ve just moved to a flat and there’s no designated space for the fridge in the kitchen, hovewer I moved to the kitchen anyway but there’s no sockets on that wall so I wanted to run an extension cord along the wall and above the door. The extension si 5meters. Do you think that will be OK? Thank you :)

Andy Trigg (Whitegoodshelp)

Likely replying to Justyna Litwin Martinelli

Thanks Justyna. Yes that should be fine as long as it’s good quality and in good condition. Fridges don’t use much electricity so the risk of overheating is far less than on something like a tumble dryer or washing machine. At the end of the day, no matter what manufacturers say about avoiding using extension cables, extension cables exist. They are sold, sanctioned by the government, and they exist solely so that we can extend the length of wall sockets. So as long as they are used sensibly, not overloaded and ideally kept as short as possible there should be perfectly fine.

Erica Ling 3 replies Hello, the only wall socket available for my combi grill/ oven/microwave is about 2 cms too far. All the advice online seems to be to never use an extension with a microwave. Please cheer me up and tell me this aint necessarily so.

Hello, the only wall socket available for my combi grill/ oven/microwave is about 2 cms too far. All the advice online seems to be to never use an extension with a microwave. Please cheer me up and tell me this aint necessarily so.

Andy Trigg (Whitegoodshelp)

Likely replying to Erica Ling

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.

Andy Trigg (Whitegoodshelp)

Likely replying to Erica Ling

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”.

Andy Trigg (Whitegoodshelp) 2 replies Yes Dennis.
Francis

Likely replying to Andy Trigg (Whitegoodshelp)

Hi Andy,

I am looking at connecting my tumble dryer, which is several inches short of the socket, via a single socket extension. The extension cable length I am looking at will either be 20 or 50cm so quite short. I will ensure it is 13 A and 3 core. Is this correct and adequate? Further, the extension will connect to a twin socket on the wall. Do I need to refrain from using the other wall socket at the same time the dryer is on, as that shouldn’t be a problem?

Many thanks – this is an excellent site that will hopefully help resolve my issue!

Kind regards

Andy Trigg (Whitegoodshelp)

Likely replying to Francis

Hello Francis. Yes that’s correct. Ideally the extension lead should be as short as possible. You could cut the extension cable down so it’s not overly long and fit a good quality plug to it. Especially if it’s really long. If you wanted to be fastidious about it you could make your own extension cable by cutting it to length as just described and replacing the block extension sockets with a single extension socket. In fact I’ve just found a pretty good single socket extension cable here

https://www.amazon.co.uk/SMJ-Electrical-B1W2MP-Trailing-Polybag/dp/B0076V71TY/ref=pd_lpo_vtph_107_bs_t_1?_encoding=UTF8&psc=1&refRID=AVZTEDBBNEWQH6FT91CQ

With an appliance drawing so much current the ideal is no extension socket. But if one is required the shorter the better and preferably a single socket instead of those multiple sockets.

Regarding using both sockets at the same time there seems to be conflicting advice and opinion about it. To be totally safe ensure nothing else is plugged in that also draws a lot of current such as a fire, dishwasher or washing machine. According to one source twin sockets can endure only 13 Amps but other sources say they can take much more. You may find this thread of interest
26 amps from twin 13 amp socket

If necessary, you could plug 2 appliances in if you could ensure they didn’t run at the same time.

Steve 2 replies This is probably a stupid question but I have a washer and dryer that I want to plug into the same plug. I am aware of the one device per plug rule. However, the plug is hidden behind the washer and it's a nightmare to get at it if I want to swap plugs. As such, is it a problem if I run both washer and dryer through an extension lead to the same plug but only ever run one at a time? Both appliance cables have 13a fuses, so does the extension cable, the wall plug is 25a. I am renting so can't change the electrics. Thanks,

This is probably a stupid question but I have a washer and dryer that I want to plug into the same plug.

I am aware of the one device per plug rule.

However, the plug is hidden behind the washer and it’s a nightmare to get at it if I want to swap plugs.

As such, is it a problem if I run both washer and dryer through an extension lead to the same plug but only ever run one at a time?

Both appliance cables have 13a fuses, so does the extension cable, the wall plug is 25a.

I am renting so can’t change the electrics.

Thanks,

Andy Trigg (Whitegoodshelp)

Likely replying to Steve

Hello Steve. There’s no one device per plug rule. The rule is only related to the amount of power drawn by any combination of devices. The maximum is 13 Amps. A washing machine and dryer will greatly exceed 13 amps so they should not be run at the same time from any wall socket or extension lead. However, plugging them into the same extension lead will do no harm other than allow the two appliances to potentially be put on at then same time causing overloading. If you are in a position to ensure that never happens then you could leave them both plugged into the same socket.

Conversely you could have 6 devices all running from an extension socket with no issues if they are all devices that use very little power and their combined consumption is less than 13 amps (in the UK).

Steve

Likely replying to Andy Trigg (Whitegoodshelp)

Thanks Andy, that’s what I thought! I was just getting confused from reading other forums and thought I’d check!

Sheogorath 2 replies @ Andy Trigg: You're right. I've double checked the fuse in my TV and it's only 5 amps, which seems to work well enough. I must have had a false memory when writing my previous post.

@ Andy Trigg: You’re right. I’ve double checked the fuse in my TV and it’s only 5 amps, which seems to work well enough. I must have had a false memory when writing my previous post.

Andy Trigg (Whitegoodshelp)

Likely replying to Sheogorath

Thanks Sheogorath, heating elements use all the power. Everything else is relatively minor in comparison.

Sheogorath

You’re welcome, Andy. Truth is, I probably got the TV mixed up with my mum’s hairdryer, which seems like a small appliance not requiring much power, but does have a 13 amp fuse if I recall correctly from when I checked (which I do in case they ever need changing, which they haven’t thus far).

Julie Fielden 1 reply Hello Would you have any idea about the best way to set up electrical appliances in a caravan awning? I'm looking to have 2 freezers a tumble dryer a dishwasher and washing machine. Separately there will be an air fryer and a nutri bullet and induction hob would be very grateful for your advice thankyou

Hello
Would you have any idea about the best way to set up electrical appliances in a caravan awning? I’m looking to have 2 freezers a tumble dryer a dishwasher and washing machine. Separately there will be an air fryer and a nutri bullet and induction hob would be very grateful for your advice thankyou

Andy Trigg (Whitegoodshelp)

Hello Julie. I can’t really advise much because I have no idea about what kind of electricity supply you have installed and its limits. If by any chance you have a normal supply with several plugs, it should be no different from a normal house or kitchen. In other words, each 13 amp plug can take literally 13 amps maximum.As tumble dryers, dishwashers, and washing machines all you was very close to 13 amps when heating up, they need to be in their own separate socket. Something like a couple of freezers would usually be able to be plugged into adapters or extension leads although ideally everything would have its own socket. You can get a good idea of how many amps certain appliances use here https://www.twothirtyvolts.org.uk/socket-overload/

Linda 1 reply Hi I need to plug my washing machine into an extension lead can you let me know which one to use that will be safe

Hi I need to plug my washing machine into an extension lead can you let me know which one to use that will be safe

Andy Trigg (Whitegoodshelp)

Hello Linda. The best method would be to make one yourself, or get one made up by someone who knows what they are doing. I’ve just updated my article adding a section called, “Make your own extension cable” with a link to some extension sockets that could be used. Alternatively, it’s difficult to be sure what to buy because there are so many rubbish quality electrical products online, even on the big famous sites.

Try to use one with as short a cable as possible. And try to use one with a few extension sockets as possible. In other words, if your washing machine’s cable is just a couple of feet short of a wall socket. Use an extension cable with just 1 m, and not six gang 3 m cable. If you need to order online I would look on somewhere like Screwfix who should always be selling pretty decent quality products.

If you buy one from a DIY store, again you should expect that they would be at the very least reasonable quality.

Adrian 1 reply I have been very reluctant to use any socket adapter even for low rated appliances. An old fire fighter told me that they spoil the jaws on your socket and cause fires that way. I have never found any evidence to back this up, I was looking for some today when I found your website. Presumably if you had anything to say on this you would have mentioned it above.

I have been very reluctant to use any socket adapter even for low rated appliances. An old fire fighter told me that they spoil the jaws on your socket and cause fires that way. I have never found any evidence to back this up, I was looking for some today when I found your website. Presumably if you had anything to say on this you would have mentioned it above.

Andy Trigg (Whitegoodshelp)

Hi Adrian. My old neighbour was a fireman, and he told me the same over 25 years ago. I would think one would need to be heavily overloaded though, and with appliances that use a lot of electricity. Maybe people plugged in a washing machine and dishwasher – that would overload for sure.

Here is a good example of what they mean –
https://www.whitegoodshelp.co.uk/wordpress/wp-content/uploads/2022/12/Mains_adaptor.jpg

That is one of my adaptors with a large wi-fi adaptor plugged in. It is heavy, and as you can see, it causes the adaptor to drop. The live and neutral prongs in the wall socket are likely to be slightly prized further apart. This could create a small gap between the top of the prongs on the plug and the top of the prongs inside the socket.

So if a large amount of current is drawn there could be small sparks jumping across the gap, which under certain circumstances could create heat.

However, even though I sometimes also plug an electric oil heater into it, I’ve never noticed any excess heat, and I’ve checked. Under normal circumstances, the hi-fi Amp and wi-fi adaptor hardly draw any power at all, and I can’t imagine how it could create any dangerous heat. However, I hope that’s a good explanation :)

Wendy Boddey 1 reply Got a 10 amp can I run my fridge freezer off it x

Got a 10 amp can I run my fridge freezer off it x

Andy Trigg (Whitegoodshelp)

Likely replying to Wendy Boddey

Hello Wendy. A 10 amp extension lead? Yes a fridge freezer shouldn’t use anywhere near 10 Amps. I wouldn’t use a washing machine, dishwasher or tumble dryer from it though.

Caroline 1 reply Hi I want to know if it's safe to plug a tabletop fridge and a kettle into the same 2 socket extension cable?

Hi I want to know if it’s safe to plug a tabletop fridge and a kettle into the same 2 socket extension cable?

Andy Trigg (Whitegoodshelp)

Likely replying to Caroline

Hello Caroline. To be sure you would need to work out the exact wattage of both appliances and divide by the voltage to get how many amps they use combined. The instructions are in my article. However, most kettles are likely to use very close to 13 amp so shouldn’t really be run with any other appliance.

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