Electrical Advice?

[ChrisT70]

I don't want to complain about your contribution, but increased resistance would cause less heat. If the installer had used 1mm or 1.5mm lighting cable to connect sockets rather than 2.5mm socket cable, then I would not expect the plugs to get warm, the wiring in the walls would be dropping the voltage and warming up the walls along the whole of the run from the supply.

 

This fault will be caused by a bad connection in the terminal or a cheap socket with a weak connector which does not tightly hold onto the plug prong.

I supect the real reason for the plug heat will be arcing and sparking from a poor connection.

 

your not quite right either with the comment about high resistance causing less heat. a local high resistance due to a poor connection will cause thermal cycling and degrade the connection even more, leading to more heat and therefore more burning and eventually damage to the cable. typically you might end up cutting a cable back 10inches or more after a connection has burnt up to get back to good copper, the rest will be blackened and have lost its nature and wont carry as much current. you are referring to an overall circuit resistance with regard to undersize cables, they would indeed get warm, if continually carrying overload current or current more than their designed maximum, eventually they will also get hotter, which further degrades their current carrying capacity, leading to it getting hotter still, a vicious circle.

 

the plug getting hot is as you say almost certainly due to either a loose connection, dirty connection, burnt up connection but typically with bigger loads the heat generated within the poor connection gets worse as it eventually burns away the cable /pins etc, its a cumulative effect that gets worse not better.

[ChrisT70]

Is there any electricians out there who can give me a bit of advice about the problems I'm having in my flat? When I plug anything in that generates heat - like a convection heater, an iron etc, the "live" pin on the 3-pin plug in the wall socket gets really hot... to the point of being a fire hazard! I only realized this when my covection heater plug got so hot that the wall socket began to melt! Also, my light bulbs go all the time - even the so-called "long-life" bulbs only last a couple of months - and when they go, they don't just pop when I flick the light switch on - they sort of explode, with a loud bang, the glass part of the bulb is blown out and just the metal bayonet collar left in the bulb holder socket. There's also quite a bit of black soot around the blown out bulb and the socket.

 

I know I'm going to have to get a qualified electrician out to sort this sooner rather than later, before I'm burnt to death in my bed, but I'm curious to know what might be causing this to happen - and more to the point, how big a job and how complicated a job would it be to put it right? I live in fear of a huge electricians bill.................

 

back to your original post, you need to get the sockets and wiring checked now, rather than later, as you will almost certainly find some poorly connected cables, pins, and possibly burnt wiring. if its one circuit only then it might run to a few hundred pounds at worst to rewire, if the entire installation is all poor then any competent electrician will give you a full and proper report and an estimate, which will allow you to compare prices with other companies.

[biotechpete]

I don't want to complain about your contribution, but increased resistance would cause less heat. If the installer had used 1mm or 1.5mm lighting cable to connect sockets rather than 2.5mm socket cable, then I would not expect the plugs to get warm, the wiring in the walls would be dropping the voltage and warming up the walls along the whole of the run from the supply.

 

This fault will be caused by a bad connection in the terminal or a cheap socket with a weak connector which does not tightly hold onto the plug prong.

I supect the real reason for the plug heat will be arcing and sparking from a poor connection.

 

Then it would have been easy, simply not to!

 

I offered helpful and correct advice. You will note the OP states that it's the live pin on any heating appliance in multiple outlets and the chances of having that many connection faults are slim. Clearly the problem is worsening suggesting degredation in the circuits but it might be difficult to notice the cables heating in the walls.

[Obelix]

On a high current device, if only the live pin is getting warm, and that's warm not hot, then don't worry. The fuse inside will be running fairly warm, because that's how fuses blow - they melt. If you have a fuse rated at 13A (which means it'll blow at a figure a fair bit more) it's still run quite warm and that will eventually heat up the live pin.

 

If it's so hot that you cannot hold it though, there is something wrong. Are the pins shiny brassy or have they gone dull?

[ChrisT70]

On a high current device, if only the live pin is getting warm, and that's warm not hot, then don't worry. The fuse inside will be running fairly warm, because that's how fuses blow - they melt. If you have a fuse rated at 13A (which means it'll blow at a figure a fair bit more) it's still run quite warm and that will eventually heat up the live pin.

 

If it's so hot that you cannot hold it though, there is something wrong. Are the pins shiny brassy or have they gone dull?

 

i think the op mentioned it had started to melt an outlet, something is wrong there.

[sandie]

On a high current device, if only the live pin is getting warm, and that's warm not hot, then don't worry. The fuse inside will be running fairly warm, because that's how fuses blow - they melt. If you have a fuse rated at 13A (which means it'll blow at a figure a fair bit more) it's still run quite warm and that will eventually heat up the live pin.

 

If it's so hot that you cannot hold it though, there is something wrong. Are the pins shiny brassy or have they gone dull?

 

Afuse at the rating will blow in half a cycle regardless of the temp if you are in any doubt look at BS 88-6.

You might also look at BS 546.

 

If your advice is "dont worry" then I think you are giving false comfort to someone and that is very dangerous.

 

The installation requires checking like now.

[sandie]

Is there any electricians out there who can give me a bit of advice about the problems I'm having in my flat? When I plug anything in that generates heat - like a convection heater, an iron etc, the "live" pin on the 3-pin plug in the wall socket gets really hot... to the point of being a fire hazard! I only realized this when my covection heater plug got so hot that the wall socket began to melt! Also, my light bulbs go all the time - even the so-called "long-life" bulbs only last a couple of months - and when they go, they don't just pop when I flick the light switch on - they sort of explode, with a loud bang, the glass part of the bulb is blown out and just the metal bayonet collar left in the bulb holder socket. There's also quite a bit of black soot around the blown out bulb and the socket.

 

I know I'm going to have to get a qualified electrician out to sort this sooner rather than later, before I'm burnt to death in my bed, but I'm curious to know what might be causing this to happen - and more to the point, how big a job and how complicated a job would it be to put it right? I live in fear of a huge electricians bill.................

 

I will agree with most of the posts, but you need to have the electrical system checked ASAP. The protective devices at your fuse board are not doing the job they were designed for, please do it now before you regret it.

[Obelix]

Afuse at the rating will blow in half a cycle regardless of the temp if you are in any doubt look at BS 88-6.

You might also look at BS 546.

 

If your advice is "dont worry" then I think you are giving false comfort to someone and that is very dangerous.

 

The installation requires checking like now.

 

BS546 is the old round pin stuff that was superseded after the war, and fuse G (88-6 now also superseded) are the clip ins in the distribution board. I'm talking about the small cartridge fuses in the plug, which is BS1362.

 

Now, take a look at the spec sheet for a compliant fuse http://www.farnell.com/datasheets/10867.pdf and you can clearly see that a small overload, say 200% rated it blows in 0.2 seconds. That's ten cycles at 50Hz.

 

Run it at say one and a half rated power and it will take minutes - well over 100s according to that chart. At perhaps 1 and a quarter overload it'll never blow.

 

If you are giving out false advice on old standards, then I think that also is perhaps rather dangerous. Nothing I've said is anything to the contrary and has indicated what is safe, and what is not safe, and I'm sure the OP is perfectly capable of determining that the melting is not safe.

[Obelix]

i think the op mentioned it had started to melt an outlet, something is wrong there.

 

Yes that's why I said if it's so hot you cannot hold it then there is a problem.... impossible to hold is about 48C for most people and if it's above that then there is a problem, as the OP has said...

[phawley]

I would be checking for high voltage, this can be caused by a neutral fault underground or at the local substation.