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I have one electrical socket at home on which I put a plug multiplier (with a very small cord) and I plug two machines on it : a wahsing machine and a tumbler dryer.

I was about to ask a company to add a water heater on that same plug, but I tought it might be too much amps. So I tried to do a bit of calculation.

The circuit breaker on that socket is 16A. Looking online, a washing machine has a maximum power consumption of 2,200 W, so 10A (220 V).

(I looked in the user manual but they did not indicate the maximum power consumption)

It is similar for a tumbler dryer.

So my first confusion is this : if both max consumption is 10A then why my 16A circuit breaker never went off ?

Second question : I read online that I can make my electrical wires burn if I put too many machines on the same socket. However, I thought the circuit breaker was here to protect that from happening (by jumping if the amps used are too much). What am I missing?

Third : I thought of buying a plug that measures power used through that plug. Is that appropriate to measure the instant power consumption (to make sure I am not overloding my socket)?

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    A 16A circuit breaker? I'd like to see a picture please.
    – MonkeyZeus
    Dec 3 '20 at 19:39
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    What country are you in? Electrical systems and the codes that govern them vary, so it'll affect the answers.
    – Nate S.
    Dec 3 '20 at 20:42
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    @J... OP didn't specify a country so I believe USA is de facto on this predominantly American site. OP did end up providing a link to their circuit breaker but it still doesn't tell me what country they are in.
    – MonkeyZeus
    Dec 4 '20 at 13:14
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    Hi all, thanks for your help. This is for Spain (230V, 50Hz)
    – DevShark
    Dec 4 '20 at 17:47
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    @MonkeyZeus No picture, but I can guarantee you that where I live (the Netherlands), 16A is the default for residential circuits; so 16A breakers are incredibly common here.
    – marcelm
    Dec 4 '20 at 22:31
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There are 2 issues here.

First, most socket splitters are cheap. They are made for cell phones, not washer-dryers. And so they tend to burn up even if you use them within their spec, because most of them are complete rubbish - watch "BigClivedotcom" and other teardown videos on Youtube. It would be better if you had proper receptacles fitted from top tier vendors who make receptacles.

Second, it's not "how many things", it's How much those things draw in practical power. You can measure that in amps or VA. (VA is volts x amps). VA more accurately reflects the heating effects on wires. It is similar to "watts" but not the same, especially on motor loads.

So for instance you can have a hundred cell phone chargers because they're like 10 VA each, so 100 phones is 1000 VA or about 4.5 amps. Easy.

But only one large appliance like a dryer.

You seem to have a handle on identifying the appliances' amps or VA and adding up the amps. It's true, you can get away with short term overloads; breakers are designed to allow that so that motors can start etc. Wires have mass, and take some time to heat up, so it is reasonable to allow short term overloads.

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  • Washers and dryers are predominantly heater loads, IIRC, and generally through resistive heating. For resistive heating, Watts and VA's are identical.
    – MSalters
    Dec 4 '20 at 9:26
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    @MSalters -- in North America, that's true for dryers, but that's not true for today's dryers in the rest of the world (where heat pump dryer tech is catching on for efficiency reasons), nor is it really all that true for washers (especially those that don't have built-in heaters or boosters) Dec 4 '20 at 12:50
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    Upvote for referencing Big Clive.
    – Ian Kemp
    Dec 4 '20 at 15:48
  • If it's a gas dryer, it will use electric for tumbling and gas for heat, then it will be highly inductive because of the motor to run the tumbler.
    – Ben
    Dec 5 '20 at 1:25
  • The answer should probably reference 'peak current' vs. 'continuous current'.
    – Ben
    Dec 5 '20 at 1:25
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You're not blowing fuses/tripping breakers because each appliance draws a maximum of 10A (I think that's what you're saying). However, they don't always draw 10A - they usually only draw that much power at startup* - i.e. when the dryer motor starts spinning it may take up to 10A to get it moving, but once moving, it doesn't draw nearly that much to keep going. Same for the washer. So long as they're not both drawing 10A each at the same time your breaker is not going to trip.

I would guess that you're not in the US (16A is not a breaker size used here), but I'd recommend looking at your local code. It may not be to code to have those appliances all on one circuit, to say nothing of having them on a "plug multiplier". I presume that this is some sort of power-strip - multiple outlets that you can plug into one outlet in the wall.

Generally speaking, fixed appliances such as washer/dryer and especially a water heater should be on their own dedicated outlets if not dedicated circuits.


*It's like your family car. The engine may produce 150BHP, but it doesn't do that all the time. It may only produce that much power at 7000RPM - you probably don't accelerate that hard, so you never get that much. However, the tach indicates a higher RPM (thus, higher BHP) during acceleration than while you're cruising down the motorway.

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  • I'm in a 16A sort of area - yes, I'd agree proper sockets for each device are an immediate good start (as noted elsewhere, most 4-way adapters are rubbish). While you've got an electrician doing that, have them check the wiring - it's quite possible you can upgrade the 16A breaker with a 32A one - but it depends on the wiring and what's normally put on the rest of the circuit. I suspect those three devices are still a bit of a tall order for one circuit, but again, a professional will advise. Dec 4 '20 at 9:24
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    In particular, the washing machine will only draw that much when heating the water, though the motor draw when spinning up will be a few amps
    – Chris H
    Dec 4 '20 at 9:25
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Not an ideal setup you have now, and you are correct to be doubtful about adding yet more load onto it.

"Why hasn't it tripped the 16A breaker" comes down to "The ACTUAL load of your ACTUAL washing machine and dryer, and whether you use them in series (one after the other) or both at the same time (put a load in the dryer and start the washer again.)

The "Maximum load of an appliance as found on the internet" will usually differ from the "actual load of a particular appliance in your house," and the particular appliance in your house is the one that matters to the circuit breaker in your house.

If you only use the appliances one after the other, both could be drawing 15.99 amps and not trip the breaker.

If you use them at the same time, presumably the combination of the two is somewhat less than 16 amps, or at least is that, as you use them. There might be some combination of settings and options you don't use which might cause an overload, or there might not be.

In any case, it would be advisable to run a new circuit for a water heater rather than adding an additional load onto the circuit in question. It's also generally preferable to provide a socket for each major/permanent appliance, rather than running two of them off of a multiplier on a single socket. Depending on your location, it might even be legally required.

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I think there are at least three factors at work here, cycling heat elements, motor load current, and circuit breaker style.

The dryer won't operate at full current all the time, most have heat elements that cycle to maintain setting. Even high temp doesn't operate full time at full current.

The labels on motors are typically FLA, full load amperage. It is the current at full load. Start up current is much higher, but drops quickly as the motor reaches full speed. Except for some low current motors the current will be less than full load when loaded to less than full load.

The last factor is breaker design, there is wide variation of trip timing for fuses and breakers. I don't know what is in use, but the typical circuit breaker used in residential panels are what is described as thermal-magnetic. The magnetic function trips quickly under short circuit condition, and thermal effect trips on overload. Most often the thermal trip is on an inverse time curve, high overloads trip quickly, low overloads trip slowly. Each model of breaker is a little different but many will hold 110% and some up to even 125% indefinitely. You may be able to locate the trip characteristics of your breakers online.

So when you combine these factors it is not surprising that you haven't experienced settings and loads that would trip the breaker.

Wires are specified to have a safety factor, for instance the typical 20A circuit in the US uses wire rated by UL for 25 or 30A, which a major portion of that rating is resistance of damaging the insulation by heat caused by current. You are likely pushing the limit, but if the breaker hasn't tripped then the wire has likely not suffered much damage.

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Note that your two appliances are motor driven. Motors use power in proportion to the mechanical load presented. (while startup load may be high the motors have start capacitors for that) If you wash few clothes the current the washer uses is lower than if you wash many clothes if you dry few clothes the current used is less than if you dry many clothes or at a hotter setting. The max current setting on the appliance is also not a hard and fast one, either. It COULD be based on the max load that will cause the thermal overload in the motor to trip - or it could be a fictitious marketing bit of rubbish - for example I have an air compressor that proudly claims to be a "5 HP" compressor that is powered by a motor that has a max current draw of 15A at 120v - nowhere near "5 HP" As long as the appliance ACTUALLY draws LESS than the claimed max, it's safe to use since the manufacturer is basically pushing responsibility for safe usage off on the consumer with no downside on a large appliance.

A water heater is a resistance device and it's load has nothing to do with how cold the water is in the tank - it's either "on full" or it's "off full"

Depending on the breaker is dangerous. Breakers are for emergency protection in case common sense fails. Frequently tripping them leads to breakers that fail and don't trip at all when you really need them.

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  • Air compressors and vacuums are poor examples as there horsepower rating is usually based on locked rotor current not full load amps as code requires. In years past your water heater analogy was accurate but less so today with electric that use SCR’s , and heat pump style that run at variable rates.
    – Ed Beal
    Dec 15 '20 at 16:13
  • All good points. Baseboard heaters now are also headed that direction since they have come out with smart digital thermostats for them that also use PWM. Dec 16 '20 at 12:59
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220V grid,16A breaker looks like a continental Europe.

I use exactly the same setup with washing machine and dryer plugged in a single 16A socket protected by the same 16A breaker for quite a while (~10 years). No single breaker trip, ever.

The reason why this works:

  1. the washing machine and the dryer are usually used sequentally - you have to wash something in order to dry it afterwards.
  2. neither the washing machine nor the dryer run always at their rated power.

The washing machine uses the heater element (the most power-hungry part) for a few minutes after the start and then cuts it off. Only the motor and the valves are used afterwards, the motor consumes few tens of watts when rotates the drum during the washing cycle and 200-400W when spins.

The dryer also heats up the air inside for less than a minute and then cuts the heater off, switching it on only for a short periods to maintain the temperature. If the dryer is heatpump-based, the rated power is consumed only for 1-2s when the compressor starts, then it draws like 400-500W and is also interrupted periodically.

  1. The breaker, as well as the wires and the socket, have some tolerance for temporary overloads.

Yes, the breaker is expected to protect everything else from overload, but a 16A breaker will allow for 1-2 minutes 20A load. In your setup, this never happens even if you time the both machines to turn on their heaters together.


A plug that measures the consumed power is a useful device - especially if you like to know where the electricity bill goes. Most of them have a memory for a maximum load, show the instant measure as well as accumulating function (just like the electricity meter used by the utility company).


A water heater on the same circuit is a big NO. (but see below)

Water heaters are usually 2000-3000W (9-13A, volume or tank heaters) or 6000-10000kW (25-40A, instant or tankless heaters).

What's more, a volume water heater usually draws its rated power for prolonged periods (hours) so you cannot really expect it not to coincide with other appliances drawing power.

The only way a water heater can safely coexist with some other appliance is time separation - say, water heater has power-on timer. It turns on only between 04:00 and 06:00 early in the morning when no one would use neither the washing machine nor the dryer. (Yes, I did use this setup for a while with no ill effects other than not having hot water for more than two showers)

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