Questions about electricity

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Fishnut
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Questions about electricity

Post by Fishnut » Tue Sep 14, 2021 9:38 am

My sister and I are in a silent minor war and I'd like to know who is right. It's about sockets where you can turn them on and off (e.g.).

I leave them switched on when I'm not using them. She insists on having them off, even when there's nothing plugged into them. This frustrates me because I don't realise and then wonder why things won't work/charge. My leaving them on clearly frustrates her because she thinks they're wasting electricity. It's been too long since I studied anything relevant to be able to make a case for or against this. So my questions are:

1) Do sockets without anything plugged into them draw any electricity when they're switched on?
2) Do sockets with something plugged into them but not being currently used (e.g. unused kettle) draw any electricity?
3) Do sockets with chargers plugged into them but not being currently used draw any electricity?
4) If the answer to any of the previous questions are "yes" are any of these draws enough to impact an electricity bill?
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Re: Questions about electricity

Post by bob sterman » Tue Sep 14, 2021 10:17 am

I think the answers are...
Fishnut wrote:
Tue Sep 14, 2021 9:38 am
1) Do sockets without anything plugged into them draw any electricity when they're switched on? NO
2) Do sockets with something plugged into them but not being currently used (e.g. unused kettle) draw any electricity? NO for kettle, toaster etc. YES for TV, PC, etc
3) Do sockets with chargers plugged into them but not being currently used draw any electricity? YES
4) If the answer to any of the previous questions are "yes" are any of these draws enough to impact an electricity bill? IT DEPENDS!

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Re: Questions about electricity

Post by Gfamily » Tue Sep 14, 2021 10:19 am

Fishnut wrote:
Tue Sep 14, 2021 9:38 am
My sister and I are in a silent minor war and I'd like to know who is right. It's about sockets where you can turn them on and off (e.g.).

I leave them switched on when I'm not using them. She insists on having them off, even when there's nothing plugged into them. This frustrates me because I don't realise and then wonder why things won't work/charge. My leaving them on clearly frustrates her because she thinks they're wasting electricity. It's been too long since I studied anything relevant to be able to make a case for or against this. So my questions are:

1) Do sockets without anything plugged into them draw any electricity when they're switched on?
2) Do sockets with something plugged into them but not being currently used (e.g. unused kettle) draw any electricity?
3) Do sockets with chargers plugged into them but not being currently used draw any electricity?
4) If the answer to any of the previous questions are "yes" are any of these draws enough to impact an electricity bill?
1) No
2) Not if it's not got a 'Standby' mode
3) It may, but
4) If the charger isn't warm to touch, I wouldn't worry.
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
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Re: Questions about electricity

Post by shpalman » Tue Sep 14, 2021 10:25 am

Fishnut wrote:
Tue Sep 14, 2021 9:38 am
My sister and I are in a silent minor war and I'd like to know who is right. It's about sockets where you can turn them on and off (e.g.).

I leave them switched on when I'm not using them. She insists on having them off, even when there's nothing plugged into them. This frustrates me because I don't realise and then wonder why things won't work/charge. My leaving them on clearly frustrates her because she thinks they're wasting electricity. It's been too long since I studied anything relevant to be able to make a case for or against this. So my questions are:

1) Do sockets without anything plugged into them draw any electricity when they're switched on?
2) Do sockets with something plugged into them but not being currently used (e.g. unused kettle) draw any electricity?
3) Do sockets with chargers plugged into them but not being currently used draw any electricity?
4) If the answer to any of the previous questions are "yes" are any of these draws enough to impact an electricity bill?
1. No
2. No (unless it's something like a TV with a standby setting and an led lit up on it, but standby power is a lot less than it used to be)
3, 4:

https://what-if.xkcd.com/35/
For example, people worry about leaving disconnected chargers plugged into the wall for fear that they’re draining power. Are they right? You can use heat flow to come up with simple rule of thumb: If an unused charger isn’t warm to the touch, it’s using less than a penny of electricity a day. For a small smartphone charger, if it’s not warm to the touch, it’s using less than a penny a year.
molto tricky

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Re: Questions about electricity

Post by tenchboy » Tue Sep 14, 2021 10:41 am

Be aware also, and this with by Fire-Monitor badge on, that anything that is left plugged in on standby might create a fire source if it becomes old or faulty and thus hot; or is a cheap import that has bypassed trading standards (I'm thinking of those christmas toys that create a roaring flame when left switched on to charge up overnight).
I have an old lappy that sometimes cycles between warm and very warm: it is never left plugged in overnight.

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Re: Questions about electricity

Post by Gfamily » Tue Sep 14, 2021 10:56 am

On the other hand, you need to remember that 'being right' doesn't mean you win the argument.
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
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Re: Questions about electricity

Post by Fishnut » Tue Sep 14, 2021 10:58 am

The biggest thing that get left turned on at the socket overnight (kitchen equipment aside) is my laptop charger, though it's not plugged into my laptop (unless I forget to stop it from charging). My sister has a extension board in her bedroom with various chargers plugged into it that doesn't get turned off but god forbid I forget to turn the kitchen socket off even when there's nothing plugged in it.
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Re: Questions about electricity

Post by Martin_B » Tue Sep 14, 2021 11:10 am

Do you have small, but curious children in the house? The sort who might get hold of something conductible and poke it into the hole in the wall?

Even though I don't have any small but curious children in my house I turn off unused sockets anyway, simply because I think it's a good habit to get into for the very very remote chance of something going wrong when my friend's small but curious children are around. I know that it's an over-abundance of safety, but for the effort involved it's turning a very very remote chance into practically zero.*

[* I also know that the probability of the socket having a short circuit which ends up causing a fire is probably greater than any other risk, and I don't know if turning the switch off will reduce this probability or increase it, but it *feels* like it should reduce the risk.]
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Re: Questions about electricity

Post by Fishnut » Tue Sep 14, 2021 11:22 am

No, we have no small and curious children, nor any chance of having any since both sister and I are childfree. We are not in the habit of having them around, and our friends' kids are all beyond the age of sticking things in sockets out of naivety. Plus the sockets most often in contention are above the kitchen counter so out of reach of small hands.
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Re: Questions about electricity

Post by lpm » Tue Sep 14, 2021 11:29 am

Children don't stick things in sockets. It's one of the great myths.

The actual risk to children is from old appliances with damaged wiring.
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Re: Questions about electricity

Post by shpalman » Tue Sep 14, 2021 11:31 am

Do other countries even have switches on wall sockets? Italy certainly doesn't.

(Maybe Mauritius does, they use the same plugs as the UK, I don't remember.)
molto tricky

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Re: Questions about electricity

Post by Woodchopper » Tue Sep 14, 2021 11:43 am

Similar follow-up question.

I spent the summer living with my parents in law (saved paying rent).

They unplug all appliances when they aren't in use (except the freezer, fridge and things that need to be left on standby for them to function normally) because leaving the toaster, kettle, washing machine etc plugged in is a fire risk. Their plugs don't have separate switches (as they don't live in the UK).

I found this to be a bit irksome as I've never encountered an appliance that went on fire when not in use but plugged in. But I got with the programme, and I can see that there could be a fire risk if there was an equipment failure.

Back home I'm perhaps recklessly leaving things like the toaster plugged in when not in use. Am I being complacent? Or are they over cautious?

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Re: Questions about electricity

Post by Woodchopper » Tue Sep 14, 2021 11:44 am

shpalman wrote:
Tue Sep 14, 2021 11:31 am
Do other countries even have switches on wall sockets? Italy certainly doesn't.

(Maybe Mauritius does, they use the same plugs as the UK, I don't remember.)
Tends to be the UK and some former colonies. The rest of the world doesn't bother.

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Re: Questions about electricity

Post by Gfamily » Tue Sep 14, 2021 11:46 am

UK sockets are amongst the safest in the world as the two current-carrying holes have shutters to thwart children with pointy things.
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
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Re: Questions about electricity

Post by Boustrophedon » Tue Sep 14, 2021 12:32 pm

I hate switched sockets. FFS! you can just unplug things.
I have to admit to a prejudice which a attribute to my childhood and my Father. Dad had mild but annoying OCD. One symptom of this is that he would obsessively turn things off.
The standard lamp in the lounge was unusable, having been plugged into a switched socket, having a typical on off switch on the bulb holder and a f.cking in-line switch on the flex. You will note that two of these give no indication of their state, Dad would switch them all off.
The kettle would be turned off, the socket turned off and the plug pulled, every single f.cking time it was used.

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Re: Questions about electricity

Post by Boustrophedon » Tue Sep 14, 2021 12:40 pm

shpalman wrote:
Tue Sep 14, 2021 10:25 am
Fishnut wrote:
Tue Sep 14, 2021 9:38 am
My sister and I are in a silent minor war and I'd like to know who is right. It's about sockets where you can turn them on and off (e.g.).

I leave them switched on when I'm not using them. She insists on having them off, even when there's nothing plugged into them. This frustrates me because I don't realise and then wonder why things won't work/charge. My leaving them on clearly frustrates her because she thinks they're wasting electricity. It's been too long since I studied anything relevant to be able to make a case for or against this. So my questions are:

1) Do sockets without anything plugged into them draw any electricity when they're switched on?
2) Do sockets with something plugged into them but not being currently used (e.g. unused kettle) draw any electricity?
3) Do sockets with chargers plugged into them but not being currently used draw any electricity?
4) If the answer to any of the previous questions are "yes" are any of these draws enough to impact an electricity bill?
1. No
2. No (unless it's something like a TV with a standby setting and an led lit up on it, but standby power is a lot less than it used to be)
3, 4:

https://what-if.xkcd.com/35/
For example, people worry about leaving disconnected chargers plugged into the wall for fear that they’re draining power. Are they right? You can use heat flow to come up with simple rule of thumb: If an unused charger isn’t warm to the touch, it’s using less than a penny of electricity a day. For a small smartphone charger, if it’s not warm to the touch, it’s using less than a penny a year.
I use smart phone chargers (well just the works) to give a safe, cheap 5V for my doorbells, where the actual bell is 240V via an optically isolated relay.
“This wasn't just plain terrible, this was fancy terrible. This was terrible with raisins in it."
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Re: Questions about electricity

Post by science_fox » Tue Sep 14, 2021 12:57 pm

Woodchopper wrote:
Tue Sep 14, 2021 11:43 am
Similar follow-up question.

I spent the summer living with my parents in law (saved paying rent).

They unplug all appliances when they aren't in use (except the freezer, fridge and things that need to be left on standby for them to function normally) because leaving the toaster, kettle, washing machine etc plugged in is a fire risk. Their plugs don't have separate switches (as they don't live in the UK).

I found this to be a bit irksome as I've never encountered an appliance that went on fire when not in use but plugged in. But I got with the programme, and I can see that there could be a fire risk if there was an equipment failure.

Back home I'm perhaps recklessly leaving things like the toaster plugged in when not in use. Am I being complacent? Or are they over cautious?
There is a very small, but non-zero, risk of lightning strike causing such a surge that it can blow even switched off but still connected devices. I'm not sure if this is more of a fire risk than having the sockets blow anyway.

Agree with above answer to OP
Only things that are warm or have a permenantly on LED will be drawing power. You can get a smart meter (or a measuring socket) and note the lack of consumption.
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Re: Questions about electricity

Post by Sciolus » Tue Sep 14, 2021 1:05 pm

Woodchopper wrote:
Tue Sep 14, 2021 11:43 am
Similar follow-up question.

I spent the summer living with my parents in law (saved paying rent).

They unplug all appliances when they aren't in use (except the freezer, fridge and things that need to be left on standby for them to function normally) because leaving the toaster, kettle, washing machine etc plugged in is a fire risk. Their plugs don't have separate switches (as they don't live in the UK).

I found this to be a bit irksome as I've never encountered an appliance that went on fire when not in use but plugged in. But I got with the programme, and I can see that there could be a fire risk if there was an equipment failure.

Back home I'm perhaps recklessly leaving things like the toaster plugged in when not in use. Am I being complacent? Or are they over cautious?
I mostly do that (but cba unplugging the kettle, because it doesn't have a switch). It's a balance of a low-probability, high-consequence risk against a low-cost mitigation measure. I also avoid using the washing machine when I'm not in the house, as they, like toasters, have a rather poor reputation for fire risk. It's a judgement call in the absence of decent data.

And I have a fire blanket by the kitchen door, ever since that time grilling sausages without sufficient attention.

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Re: Questions about electricity

Post by dyqik » Tue Sep 14, 2021 4:31 pm

shpalman wrote:
Tue Sep 14, 2021 11:31 am
Do other countries even have switches on wall sockets? Italy certainly doesn't.

(Maybe Mauritius does, they use the same plugs as the UK, I don't remember.)
Not in the US.

They also don't generally have tamper proof sockets (they are becoming more prevalent), so you can stick pretty much anything small enough into a socket with no real force.

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Re: Questions about electricity

Post by nekomatic » Tue Sep 14, 2021 6:54 pm

In my mind switches on sockets are a) so you can switch off an appliance that doesn’t have its own switch (rare nowadays) without unplugging it, and b) to remove the risk of touching live parts as you insert or remove the plug (much less nowadays as the live and neutral pins on plugs are insulated to half way up, which they didn’t use to be).

I still switch them off before unplugging and get twitchy if I see one switched on without something plugged in though.

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Re: Questions about electricity

Post by IvanV » Tue Sep 14, 2021 7:03 pm

Gfamily wrote:
Tue Sep 14, 2021 11:46 am
UK sockets are amongst the safest in the world as the two current-carrying holes have shutters to thwart children with pointy things.
I think this is just typical British pride and self-justification. Our ridiculous electrical wiring system that results in us walking around with unnecessarily large heavy plugs, that use lots of copper, is justified because it's "the best".

I suspect the reason we require all these safeguards at the socket, that the rest of the world dispenses with, is because you can more easily get a big electrical shock off a UK socket. The UK ring main system is brilliant for getting a reliable voltage to your socket, but for just the same reason it is also brilliant for giving you a big electric shock.

It's like going, look, there are all these safeguards stopping you falling in this pool, this is a much safer pool. But that's because this is the pool with sharks in.

There are a number of human-interface issues with awkward British plugs, which present shock risks that are less likely to occur with easy to use continental plugs. The main issue is that is much physically harder to push a British plug fully home, presenting greater risk of the plug not being fully pushed in at the first attempt.

If you stick something in the earth hole, it opens up the shutters. So a common way of getting a shock is when the plug is only part way in, when the longer earth pin has opened the shutters, but the other pins are only partly inserted, and their exposed shafts are now live. There is a lot of physical resistance to pushing a British plug home. That shutter mechanism can be very stiff, and also those fat pins go into electrical clamps that can be quite stiff to lever open. So you are much more likely to end up with a British plug only partly inserted. This happens particularly when the socket doesn't have perfect access, it's half way under a bed or in a gap behind a cupboard, as is common.

So I have fairly often, for some reason or another not got a stiff plug in fully in one go, and then I'm groping around to try and finish the job off under a bed or behind a cupboard, and managed to touch a live pin. It is all very easy to say, switch the socket off before you do this. But if the switch is the far side of the poorly accessible plug, it can be difficult to operate the switch once the plug is in the socket.

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Re: Questions about electricity

Post by monkey » Tue Sep 14, 2021 7:04 pm

dyqik wrote:
Tue Sep 14, 2021 4:31 pm
shpalman wrote:
Tue Sep 14, 2021 11:31 am
Do other countries even have switches on wall sockets? Italy certainly doesn't.

(Maybe Mauritius does, they use the same plugs as the UK, I don't remember.)
Not in the US.

They also don't generally have tamper proof sockets (they are becoming more prevalent), so you can stick pretty much anything small enough into a socket with no real force.
And you sometimes get the fun of sparks if you're plugging in something with no switch.

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Re: Questions about electricity

Post by nekomatic » Tue Sep 14, 2021 7:22 pm

You can get European sockets with shutters; shutters on good quality UK sockets are operated by equal pressure on the live and neutral pins, not by inserting the earth pin; and what is it about a ring main that gives you a worse shock?
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Re: Questions about electricity

Post by Millennie Al » Wed Sep 15, 2021 1:11 am

Fishnut wrote:
Tue Sep 14, 2021 9:38 am
4) If the answer to any of the previous questions are "yes" are any of these draws enough to impact an electricity bill?
That depends on the appliance. You can test it yourself with somethoing like this: https://www.amazon.co.uk/Xpork-Monitor- ... B08K7G4XCH (found randomly - not a recommendation for that particular one) and for most items the answer isit is insignificant. I once tested a desktop PC and it consumed 11W when off (that's because you can send it a message over the network to tell it to turn on ("wake on LAN") which means it must remain slightly active. That would consume 96 units (kWh) per year which would cost you less than £20 per year. I just tested a laptop power supply when not connected to its laptop and git under 1W, so < £2/year. So even if you had a handful of such items, you'd be unlikely to notice any difference to you bills.
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Re: Questions about electricity

Post by Millennie Al » Wed Sep 15, 2021 1:23 am

Woodchopper wrote:
Tue Sep 14, 2021 11:43 am
Back home I'm perhaps recklessly leaving things like the toaster plugged in when not in use. Am I being complacent? Or are they over cautious?
You are perfectly reasonable. The risk is non-zero but minuscule. Your parents in law may remember older equipment and older wiring - or even be merely acting on their parent experiences. When there were things like valve TVs there was some risk, but nowadays its too small to worry about. The risk is so small that if someone's phone charger catches fire it may well become newsworthy worldwide.

With regard to switches on sockets, these are useful for turning off several things at once - for example, if you have an extenstion which powers a PC, monitor, and printer. They are also useful in the extremely rare situation when you try to pull out a UK plug and the top comes off in your hand, exposing the live pin. This, again, is only relevant to older appliances (or those which you had to wire up yourself), as nearly everything now comes with a moulded plug that cannot come apart.
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