Sockets in my house MELTING my plugs!

Bigtalker

All,

Very quick one - my hoover is destroying all the sockets in my house. the plau keeps melting and burning the socket turning it brown. We replaced the plug and its happening on the new one. I mentioned this to my neighbour and she said the same thing is happening with her hair dryer and straighteners.

Is this something that known to happen for a specific reason? it sounds to me like its the sockets in our houses. They were built 4 years ago.

wait4me

Perhaps the guys on Electrical forum will be better able to help you.

Sounds as if your appliances are drawing too much power from the socket and therefore could be a fuseboard issue. But I'm not an electrican.

olliewexford

the hoover is shagged. its drawing to much power? motors must have a fault ,is the fuse new when you changed the plug ?. dump it before for house goes up, i know non of us are made of money but thats scary . ps be no harm to press the test button on the rcd in the fuse board, even thought that trips for current loss . the mcb (the smaller ones on the board )should trip for current been overloaded.

wildefalcon

need more information:

How old is the house?

When was it (re)wired?

Does it have a modern fuse board?

Have there been any alterations?

It is highly likely that the wiring is dangerous. I would strongly urge you to get a decent electrician in to inspect the wiring, specifically to check for spurs from the ring main, use of 1.5sqmm wire for ring main and a broken ring.

Also to do a "megger" test on the circuit board and earth.

brightspark

Bigtalker wrote: »

All,

Very quick one - my hoover is destroying all the sockets in my house. the plau keeps melting and burning the socket turning it brown. We replaced the plug and its happening on the new one. I mentioned this to my neighbour and she said the same thing is happening with her hair dryer and straighteners.

Is this something that known to happen for a specific reason? it sounds to me like its the sockets in our houses. They were built 4 years ago.

You need to get your socket replaced, there is either a loose wire or a bad contact within the socket.

As the cable may also be damaged you should get an electrician to check it out.

Alternatively was the new plug correctly wired with all connections tight?

A fault with the vacuum would be unlikely to damage the plug (assuming it still runs and is fitted with an appropriate fuse)

wait4me

Bigtalker wrote: »

I mentioned this to my neighbour and she said the same thing is happening with her hair dryer and straighteners.

This is what worries me - the OP says its happening to all the sockets in the house and the neighbour is complaining as well

brightspark

wait4me wrote: »

Bigtalker wrote: »

I mentioned this to my neighbour and she said the same thing is happening with her hair dryer and straighteners.

This is what worries me - the OP says its happening to all the sockets in the house and the neighbour is complaining as well

Perhaps all the sockets were poorly installed with loose connections?
Get a competent electrician in to check it out.

2 stroke

I wouldn't throw out that hoover yet, get an electrician in. I have a similar problem with some sockets added a few years ago. Currenty I'm blaming the sockets, they were purchased in a large hardware store rather than an electrical supplier. The sockets that have something plugged in permanently appear fine, but the ones where items are regularly plugged in/out are showing signs of overheating. I have checked my appliances and none are drawing an excessive load.

Bigtalker

Oh gosh! This all sounds a little scary! I think I might be best placed getting a professional in. The house is only 4 years old with a modern fuse board. Nothing has been re wired or changed in anyway. We did have to change the fuse switch above our cooker as it kept blowing. The electrician at the time said it was a cheap fuse and thats why it was going.

It is true that anything I leave plugged in doesnt melt (airwirck plug ins and the sonar repellent plug ins and lamps and TV etc), just the one off stuff.

wildefalcon

Oh, God.

Celtic tiger wiring.

If you are luck it's only cheap sockets - though I doubt it. Stuff melts because too much current goes through it. Cheap sockets are usually good enough for the job - I've used them on heavy duty applications and have had no problems.


Get a decent experienced electrician in - quick! Show them the sockets, ask them to check the ring main is complete.

bbam

wildefalcon wrote: »

Oh, God.

Celtic tiger wiring.

There'll be more of these coming in the future me thinks...

Give the hoovering a break until it's all checked out.....

cabledude

There could be a couple of things wrong.

1 I don't think it's your appliance. Unless you share a hoover with your neighbour.

2 The problem is obviously with your electrics and indeed your neighbours electrics.

3 You will need to get a RECI or Safe Electric contractor to take a look at your house. Get two or three to call. More than one opinion will be needed.

4 The problem may be undersized wiring. Ring mains for domsetic sockets should use 2.5 mm Twin & Earth cables. Blue and Brown wires with a smaller bare copper wire between the blue/brown. If the cables used are 1.5 mm you are going to have to replace the lot.

5 But hopefully for you it's cheap fixtures and fittings. Switches, roses sockets breakers could be to blame. Your electrician will also check your MCB's and the RCD. He/She should also check the rating on the main switch fuse. If the sockets are cheap imports you will need to replace them with BS approved items. Get your contractor to ensure only up to standard materials are used.

Don't be concerned. Get an electrician a.s.a.p.

Best of luck.

delly

Moved from DIY to electrical

brightspark

@OP Some of the posts here are misleading and though they mention problems that the posters may have experienced are very unlikely to be relevant to your situation.

The fault you have describe is localised heating of the plug/socket.

A bad connection whether within the socket or as a result of loose terminations causes the plug-socket to have a high resistance.

Current squared multiplied by resistance equals watts
watts in this case equals HEAT which causes the melting described


The fault you described is not caused by

• undersized wiring, (the wires would heat not the plug/socket)
• Switches, roses sockets breakers (again they would heat not the plug socket)
• broken ring (theoretically the same as undersized wiring)
• Stuff melts because too much current goes through it (a domestic vacuum cleaner is hardly likely to be drawing in excess of 13A and still be working!)

(of course, given the poor standard of some electrical work I've seen, it's possible that some of the above issues exist in your house as well, but they won't cause your plugs to melt!)

In my opinion the fault is either a batch of bad sockets installed in your house (and your neighbours) or lots of poorly terminated sockets (which were probably all installed by the same person).

The fact that the airwirck plug ins and the sonar repellent plug ins and lamps and TV arn't affected may be due to the fact that all those items are relatively low wattage items so the I^2 R loss across the plug-socket is insignificant.

Zimmerframe

brightspark wrote: »

In my opinion the fault is either a batch of bad sockets installed in your house (and your neighbours) or lots of poorly terminated sockets (which were probably all installed by the same person).

Exactly what that man said, there is nothing, other than junk sockets or loose terminations in the socket box that could cause your issues.

xxtallaghtxx

I'd get onto who ever you and neighbour bought your houses from too. Together. If its sub standard work there should be some kind of come back like a "warranty" if you know what im trying to say.

exaisle

.....or seriously low voltage....

paddymick

The problem is cheap crappy sockets,I`d take a stab in the dark and say they are Powermaster..Ive came across alot of them giving the same trouble and my wholesaler had to stop selling them..

I wouldnt think there is anything wrong with your hoover either.

brightspark

exaisle wrote: »

.....or seriously low voltage....

Can you please explain how low voltage can cause plugs to melt?

Bigtalker

Ok guys - thanks for all this. I spoke to my neighbour. She had an electrician in and he said it was cheap sockets and replaced them all for her. We have one coming this Sat to have a look.

Dissapointing as this year alone we have had to replace our 4 year old gas bioler, found issues in our roof, sanded down the windows as the paint was peeling off and now the wiring. Whats next?!!

Celtic Tiger house building!!

brightspark

Bigtalker wrote: »

Ok guys - thanks for all this. I spoke to my neighbour. She had an electrician in and he said it was cheap sockets and replaced them all for her. We have one coming this Sat to have a look.

Dissapointing as this year alone we have had to replace our 4 year old gas bioler, found issues in our roof, sanded down the windows as the paint was peeling off and now the wiring. Whats next?!!

Celtic Tiger house building!!

don't forget to change any damaged plugs before using them in the new sockets

Bruthal

Bigtalker wrote: »

All,

Very quick one - my hoover is destroying all the sockets in my house. the plau keeps melting and burning the socket turning it brown. We replaced the plug and its happening on the new one. I mentioned this to my neighbour and she said the same thing is happening with her hair dryer and straighteners.

Is this something that known to happen for a specific reason? it sounds to me like its the sockets in our houses. They were built 4 years ago.

Thats purely and simply rubbish sockets. The contacts are not gripping the plug pins properly. Replace all sockets is likely needed.

Edit. Just seen post #20.

And as brightspark said, replace any plugs that have any signs of burnt or overheated pins.

cabledude

If the contractor used cheap sockets, it would be reasonable to assume that they possibly used cheap stuff everywhere. I would not like to have cheap electrical items or fittings in my house. Quite obviously cheap roses are not going to make your sockets heat up!!!! Or MCB's for that matter.

But the point I was trying to make is that cheap materials may have been used generally across your installation. When you get the electrician in, get him to check absolutely everything. Also get him to check the whole fuse board to make sure everything is tightened properly. Most of them will do this but then again the lad who did the job in the first place wasn't very concerned about what he put in. My mothers house had an extention built on 4 years ago and they fitted an extra electric shower. When the contractor installed the contactor for the shower he did not tighten the nuetral wire enough. After a while the shower stopped working. When I looked in to the board the contactor was burnt jet black. Frightening. All because this lad was weak on the screwdriver.

Best of luck...

cabledude

brightspark wrote: »

@OP Some of the posts here are misleading and though they mention problems that the posters may have experienced are very unlikely to be relevant to your situation.

The fault you have describe is localised heating of the plug/socket.

A bad connection whether within the socket or as a result of loose terminations causes the plug-socket to have a high resistance.

Current squared multiplied by resistance equals watts
watts in this case equals HEAT which causes the melting described


The fault you described is not caused by

• undersized wiring, (the wires would heat not the plug/socket)
  

Hypothetically speaking, if 1.5 T&E were used in error couldn't this cause the wiring and in turn the sockets to heat???

M cebee

cabledude wrote: »

Hypothetically speaking, if 1.5 T&E were used in error couldn't this cause the wiring and in turn the sockets to heat???

no can't see it happening

it's usually just a local socket /plug issue

3kw heating loads and the like don't help much

Bruthal

brightspark wrote: »

Can you please explain how low voltage can cause plugs to melt?

Probably heard that motors can trip overloads if the voltage is a little low. That can happen on a loaded motor alright, as the slip increases with reduced voltage. Would have no bearing on sockets though, even with motors plugged in. Meaningless.

wildefalcon

robbie7730 wrote: »

Probably heard that motors can trip overloads if the voltage is a little low. That can happen on a loaded motor alright, as the slip increases with reduced voltage. Would have no bearing on sockets though, even with motors plugged in. Meaningless.

If the voltage drops, and the wattage remains the same, then the current (amps) increases.

Higher amps, higher temperatures.

brightspark

wildefalcon wrote: »

robbie7730 wrote: »

Probably heard that motors can trip overloads if the voltage is a little low. That can happen on a loaded motor alright, as the slip increases with reduced voltage. Would have no bearing on sockets though, even with motors plugged in. Meaningless.

If the voltage drops, and the wattage remains the same, then the current (amps) increases.

Higher amps, higher temperatures.

Even if you were correct in saying that the wattage stays the same with a consequential increase in current.....the fuse in the plug top should blow before the plug top melts. I have seen 13A plugs used on welders, complete with gutter bolt instead of the fuse, that show no sign of melting.

M cebee

just a bad lot of sockets here by the look of it


-if you've a 3kw heating load and you drop from 230 to 220v

the wattage drops from 3000 to 2750 watts if i recall

-current also drops

-a 1.5 t+e wouldn't affect plug really just voltage drop and readings

Bruthal

wildefalcon wrote: »

If the voltage drops, and the wattage remains the same, then the current (amps) increases.

Higher amps, higher temperatures.

Thats completely incorrect. When voltage reduces, the resistance of the item or appliance is what remains the same, so the amps reduce, and so the wattage is less.

l will use an immersion as an example.

If its 3kw rated at 230v, then it will only be 3kw at the 230v.
3000w/230v = 13 amps

230v/13A = 17.7 ohms. This is fixed, and is what rates the immersion at 3kw only at 230v

Same immersion At 240v
240v/17.7 ohms = 13.6 amps
240v x 13.6A = 3.26 kw.

Now connect 115v to it.
115V/17.7 ohms = 6.2 amps

115 x 6.5 amps = 747 watts. Notice when the voltage is halved, the watts will be 1 quarter. If voltage is doubled to a fixed resistance, the wattage will be 4 times higher.

For an immersion to be 3kw at 115 volts.
3000w/115v = 26 amps
115v/26A = 4.42 ohms.

So the 3kw 115 volt immersion would be 1 quarter of the resistance of the 230v 3kw one.

So halving the voltage to a 230v 3kw appliance does not keep the appliance at 3kw and have a higher current to compensate. A 115v 3kw appliance will have a resistance 4 times lower than a 230v one, so it is designed to be 3kw only at the 115v.

Connect this 115v immersion to 230v and it would be 12kw, until it burnt out.

If the above 3kw 115v immersion was fed from a 230v/115v transformer, the secondary side would have 26 amps flowing into the immersion, and the primary side would have 13 amps, with both sides operating at 3kw. So the higher voltage side has a lower current flow. This is what can cause the confusion you are possibly having.

maxfresh

Get a sparks to check out the wiring ,ive seen sockets wired in 1.5 flex :eek:

sincere113

wildefalcon wrote: »

If the voltage drops, and the wattage remains the same, then the current (amps) increases.

Higher amps, higher temperatures.

robbie7730 wrote: »

Thats completely incorrect. When voltage reduces, the resistance of the item or appliance is what remains the same, so the amps reduce, and so the wattage is less.

.......................

You're wrong Robbie7730.....Wildefalcon is correct


Wildefalcon is correct because he states that the power (wattage) is the same..... In your example you are changing the power aren't you?

Example;-

Power (W) = Voltage X Current (I).

If W = 2000, Voltage is 200 (just for arguments sake for this example), then I = W/V = 2000/200 = 10A......

But like Wildefalcon states

"If the voltage drops, and the wattage remains the same, then the current (amps) increases"

So if now our Voltage is 100V;-

Again I = W/V = 2000/100 = 20A.

As you can see the current must go up to maintain 2000W power.....

M cebee

no that's not how it works

sincere113

M cebee wrote: »

no that's not how it works

In order to deliver the same amount of power to a load, if the input voltage reduces then the current must increase right?

M cebee

the power drops when voltage drops

rating of appliances is for a nominal voltage ie:230

sincere113

M cebee wrote: »

the power drops when voltage drops

rating of appliances is for a nominal voltage ie:230

Yes I agree that your statement is correct. What you are saying is correct that in practise if the supply voltage drops then output power drops proportionally.

However, what I am saying is that if the power consumed is constant and the voltage drops then the current drawn must increase. That is theoretically sound.

I work in an industry that provides a product which provides a power supply to a load. The power delivered must remain constant. e.g. 100W. The ESB (or whoever) electrical supply from the wall socket fluctuates greatly over the period of a day (210V-260V), so our product draws varying amounts of current depending on the supply voltage to maintain an output of 100W.

cast_iron

sincere113 wrote: »

However, what I am saying is that if the power consumed is constant and the voltage drops then the current drawn must increase. That is theoretically sound.

Perhaps, but makes no sense in the context of this thread, as there is no reason to think why the power would be constant. Which is probably why robbie assumed whitefalcon's input meant something other than what he was saying.

sincere113

cast_iron wrote: »

sincere113 wrote: »

However, what I am saying is that if the power consumed is constant and the voltage drops then the current drawn must increase. That is theoretically sound.

Perhaps, but makes no sense in the context of this thread, as there is no reason to think why the power would be constant. Which is probably why robbie assumed whitefalcon's input meant something other than what he was saying.

Yes we're maybe going abit OT but there are products which are designed to work off a residential supply which must deliver and maintain a specific power level. These products draw more current as the input voltage drops to a specific level and then they 'drop out' for safety purposes. It's all in PSU designs....

Therefore it is wrong to assume in all cases that as the nominal supply voltage drops that the power consumption drops and the particular product does not draw more current. Intentional or not, or in fact it is relevant to the OP query, wildefalcons statement is correct.

paddymick

sincere113 wrote: »

Yes we're maybe going abit OT.

That seems to be a common theme in these threads,The OP`s question will get answered quickly in the first few posts then the next few pages are like a competition to see who has the biggest gonads when it comes to electrical knowledge!!

Im not bashing just making an observation:)...

.G.

paddymick wrote: »

That seems to be a common theme in these threads,The OP`s question will get answered quickly in the first few posts then the next few pages are like a competition to see who has the biggest gonads when it comes to electrical knowledge!!

Im not bashing just making an observation:)...

Your wrong there Paddymick.

Utterly wrong:D

M cebee

2011 and robbie are the biggest troublemakers:D

M cebee

sincere113 wrote: »

Yes I agree that your statement is correct. What you are saying is correct that in practise if the supply voltage drops then output power drops proportionally.

However, what I am saying is that if the power consumed is constant and the voltage drops then the current drawn must increase. That is theoretically sound.

I work in an industry that provides a product which provides a power supply to a load. The power delivered must remain constant. e.g. 100W. The ESB (or whoever) electrical supply from the wall socket fluctuates greatly over the period of a day (210V-260V), so our product draws varying amounts of current depending on the supply voltage to maintain an output of 100W.

you're talking bout these gadgets
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=LE1200I&tab=features

it's hardly relevant here anyhow

brightspark

sincere113 wrote: »

Yes we're maybe going abit OT but there are products which are designed to work off a residential supply which must deliver and maintain a specific power level. These products draw more current as the input voltage drops to a specific level and then they 'drop out' for safety purposes. It's all in PSU designs....

Therefore it is wrong to assume in all cases that as the nominal supply voltage drops that the power consumption drops and the particular product does not draw more current. Intentional or not, or in fact it is relevant to the OP query, wildefalcons statement is correct.

It's not relevant to the OP query at all, the OP query concerned melted plugs which are not caused by undervoltage/overcurrent.

AND the OP mentioned a hoover, are your power supplies ever installed in vacuum cleaners?
(I'm guessing they are 'Switched Mode Power Supplies')


We are now in excess of 40 posts, the OP stated back in post 20 that they are getting an electrician in and that their neighbour with a similar problem had cheap sockets replaced.

Can we not take it for granted that anyone who answers a post in this forum understands Ohm's law etc.?

Let's stop the guessing games here and wait for the OP to report back and let us know what the electrician discovers.

Bruthal

sincere113 wrote: »

.......................

You're wrong Robbie7730.....Wildefalcon is correct

Here is what wildefalcon said

wildefalcon wrote: »

If the voltage drops, and the wattage remains the same, then the current (amps) increases.

But the wattage cant remain the same. Your confusing this with electrical science questons to find currents in different situations.

For the wattage to remain constant as voltage reduces, the load resistance has to reduce as the voltage reduces. That doesnt happen.

As i said earlier, a motor is an example of an item which can draw higher current when it has its voltage reduced, when the motor is driving a load. But in general, wattage reduces as voltage reduces, and any decent electrical loads in houses will be heating element type loads.

For wattage to remain the same as voltage reduces, and so current increases, the appliance impedence has to reduce, which happens in motors as the rotor speed reduces. But motor loads in domestic situations are small.

Bruthal

sincere113 wrote: »

In order to deliver the same amount of power to a load, if the input voltage reduces then the current must increase right?

To deliver the same amount of power with a lower voltage, requires the item to be specifically designed for the voltage in question.

A 9kw 230v shower will not be 9kw if the voltage reduces to 220v. It is only 9kw at 230v.

Calculating 9kw at 115v and getting double the current of a 230v 9kw shower, is simply because the 115v one will have elements of 4 times lower resistance than the 230v version.

It does not mean if you connect the 230v 9kw shower to the 115v that you now get double the current. The current will be half, and so the output will be 2.25kw

Bruthal

cast_iron wrote: »

Perhaps, but makes no sense in the context of this thread, as there is no reason to think why the power would be constant. Which is probably why robbie assumed whitefalcon's input meant something other than what he was saying.

Whitefalcon said if the voltage drops, but the wattage remains the same, then the current increases. Thats not what happens with appliances in real life.

sincere113

robbie7730 wrote: »

Here is what wildefalcon said

But the wattage cant remain the same. Your confusing this with electrical science questons to find currents in different situations.

For the wattage to remain constant as voltage reduces, the load resistance has to reduce as the voltage reduces. That doesnt happen.

Yes it does in some products.

Some domestic products provide quite tight output power levels irrespective of input voltage. Thats my point exactly. If I need a product which provides a tightly specified output power level, but the nominal voltage varies over the course of a day your saying its not possible to deliver a specified output power because the device can not change its impedance. THAT IS WRONG..... Its also best to refer to impedance rather than resistance when talking about ac applications.

Your examples are correct because those examples are power rated at a nominal voltage as someone mentioned earlier in the thread. However some products have a rated power over a range of input voltage.

Brightspark:
Intentional or not, or in fact it is relevant to the OP query

Sorry, I meant to say or in fact if it is relevant, meaning its not very applicaple to the OP. However it is relevant as I corrected someone with incorrect information.

Bruthal

sincere113 wrote: »

Yes it does in some products.

Some domestic products provide quite tight output power levels irrespective of input voltage. Thats my point exactly. If I need a product which provides a tightly specified output power level, but the nominal voltage varies over the course of a day your saying its not possible to deliver a specified output power because the device can not change its impedance. THAT IS WRONG.....

Where did i say its not possible? You say if you need a product which has a regulated supply. What appliances in the usual domestic setup have regulated supplies? Now we are talking about appliances, not laptop transformers/power supplies.

Its also best to refer to impedance rather than resistance when talking about ac applications.

It passed you by that i refered to resistance in the examples of heating elements, and impedence in the motor references. An element has practicaly no reactance at 50hz, so resistance is good enough for elements. What is the PF of an immersion element? I`d say its 1. If its 1, then its impedence = its resistance.

Its astonishing you mention impedence, as if to use it as another method to argue your point, and yet you cant grasp the very basic theme of the thread. Telling us that wildefalcon saying w/v = amps is correct, and that means my statement, and other posters, that reducing voltage on a normal everyday domestic load does not result in a stable power output, but reduces power output, is incorrect accodring to you.

It is not incorrect to say an appliance power output reduces as its voltage reduces, simply because you state that voltage regulators can be got and used.

Your examples are correct because those examples are power rated at a nominal voltage as someone mentioned earlier in the thread. However some products have a rated power over a range of input voltage.

Brightspark:
Intentional or not, or in fact it is relevant to the OP query

Sorry, I meant to say or in fact if it is relevant, meaning its not very applicaple to the OP. However it is relevant as I corrected someone with incorrect information.

Which is it? Correct or incorrect? My examples are correct? Unbelievable this:D. You earlier said i was wrong in the thread, now my particular examples are correct. My examples are typical household items. And becuase you sell regulators, all of a sudden other posters are incorrect when they say a reducing voltage will mean a reducing power output.

sincere113

Once again, last time though...

robbie7730 wrote: »

Thats completely incorrect. When voltage reduces, the resistance of the item or appliance is what remains the same, so the amps reduce, and so the wattage is less.

That is wrong....There are items whos impedance changes to deliver a steady output power.

robbie7730 wrote: »

l will use an immersion as an example.

If its 3kw rated at 230v, then it will only be 3kw at the 230v.
3000w/230v = 13 amps

230v/13A = 17.7 ohms. This is fixed, and is what rates the immersion at 3kw only at 230v

Same immersion At 240v
240v/17.7 ohms = 13.6 amps
240v x 13.6A = 3.26 kw.

Now connect 115v to it.
115V/17.7 ohms = 6.2 amps

115 x 6.5 amps = 747 watts. Notice when the voltage is halved, the watts will be 1 quarter. If voltage is doubled to a fixed resistance, the wattage will be 4 times higher.

For an immersion to be 3kw at 115 volts.
3000w/115v = 26 amps
115v/26A = 4.42 ohms.

So the 3kw 115 volt immersion would be 1 quarter of the resistance of the 230v 3kw one.

So halving the voltage to a 230v 3kw appliance does not keep the appliance at 3kw and have a higher current to compensate. A 115v 3kw appliance will have a resistance 4 times lower than a 230v one, so it is designed to be 3kw only at the 115v.

Connect this 115v immersion to 230v and it would be 12kw, until it burnt out.

If the above 3kw 115v immersion was fed from a 230v/115v transformer, the secondary side would have 26 amps flowing into the immersion, and the primary side would have 13 amps, with both sides operating at 3kw. So the higher voltage side has a lower current flow. This is what can cause the confusion you are possibly having.

That example is correct since you refer to a device which does not provide a steady output power and only delivers that stated power at nominal voltage. I have not once implied that such equipment in your examples impedance changes, but my point is that not all devices/items behave in this manner. Therefore you can not state that Wildefalcons statement is completely nonsense, but in truth his statement holds validity.

When refering to the opposing force to electron flow in a conductor in an ac circuit it is correct to use the term impedance since impedance describes magnitude and phase.

You quoted "An element has practicaly no reactance at 50hz, so resistance is good enough for elements. What is the PF of an immersion element? I`d say its 1. If its 1, then its impedence = its resistance."

Not true, as resistance can not define the angular component.

My opinion now is that we should stop the debate here as its not really helping the OP. If you wish to continue maybe we should start a new thread in science or something?

Bruthal

sincere113 wrote: »

That is wrong....There are items whos impedance changes to deliver a steady output power.

Any examples of household appliances that do this? Or just keep repeating the sentence?

That example is correct since you refer to a device which does not provide a steady output power and only delivers that stated power at nominal voltage. I have not once implied that such equipment in your examples impedance changes, but my point is that not all devices/items behave in this manner. Therefore you can not state that Wildefalcons statement is completely nonsense, but in truth his statement holds validity.

I can, as all he told us was how to calculate power in a given circuit, this power alters in a circuit as the voltage alters, a factor you seem to disagree with, simply because a voltage regulator can be incorporated. But they are not in the supply line of general household appliances, are they?

The power in a circuit in domestic situations changes with voltage changes, so his reply to a post asking how a dropping voltage will damage sockets is not correct in context to the OP problem, but you said he was correct, simply because he states ohms law correctly. Now thanks to you he probably believes plugging a 230v 2kw kettle into 115v will still be 2kw but at double the current. Which is not correct.

So he seemed to be suggesting the current would increase for a voltage reduction, i said it wont for the same load, you said he was correct . Now you say my example was correct. I think you should read the entire thread again, more carefully.

When refering to the opposing force to electron flow in a conductor in an ac circuit it is correct to use the term impedance since impedance describes magnitude and phase.

Magnitude and phase? Id say you read all this recently, as thats like textbook terminology there.

Again, you brought this up, even though its of little relevance here. In a resistive circuit, current and voltage are in phase. So 230v AC or DC would give the same amps. PF = 1.

There is no reactance in a resistive circuit. So in a resistive circuit, impedence = resistance. You also dispute this, so you surely are reading this stuff, but dont understand it.

You quoted "An element has practicaly no reactance at 50hz, so resistance is good enough for elements. What is the PF of an immersion element? I`d say its 1. If its 1, then its impedence = its resistance."

Not true, as resistance can not define the angular component.

I still dont know why you brought it up. Im fully aware of what impedence is compared to resistance. Again, a purely resistive heating element such as an immersion will be completely in phase. Any reactance will be so negligible that it can be disregarded.

Here, read this, it might help you. Good examples of the impedence and resistance in a purely resistive load. The immersion element i used is a resistive load, and its very safe to treat it as a resistance load, and so using a heating element as an example, i used resistance. When taking about a motor, i used impedence. So your simply nit picking over terminology. I could of course have used impedence as the term, but you picking up on that is pedantic.

My opinion now is that we should stop the debate here as its not really helping the OP

You dragged it off by nit picking at irrevalent stuff.

Now, any chance of some examples of everyday appliances which will give a constant power output with different voltages in a house? Im guessing not.

What about the hoover mentioned by the OP.
Washing machine
Dishwasher
Cooker
Electric shower
Fridge
Tumble dryer

An induction motor can change its impedence due to changing slip (load or voltage changes). A universal one can change it due to forced slowing of the rotor due to more load, from the generated back EMF reducing as the rotor slows. More useless info for you to save you googling that too.

But are you telling us the above appliances will all output a steady power if the supply voltage drops from 230v to 220v, or vice versa?

If the ESB voltage went up to 250v from 230v for a household over a bill period, the bill would be higher for the exact same appliances used for the same times. Can you explain this for us? O wait, you said power changing with voltage is incorrect, so that cant happen of course:pac:

sincere113

I give up with you..........:o