3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes this ?

[chris murphy]

"Hello All",


I was visiting an elderly family member when she mentioned that a 3 KW Fan Heater that she uses makes the Plug `Pins` Hot - I was only able to check this by trying out the Heater and feeling the Plug `Pins`.

These were Hot - even when the Heater was run on the 1 KW Setting - Also I tried the Heater in various Sockets - including the 2 on Kitchen Ring - the Pins were Hot when used on ALL Sockets that I tried throughout the Home - which surprised Me.


I believe that the Home was rewired only about 5 Years ago - I mention that only to establish that the Wiring is `New` Twin and Earth - the Consumer Unit was also changed at that time.


I might expect to be able to feel some Heat from the `Pins` after the Heater has been running on 3 KW - ? BUT not to the extent where they are actually `Hot` [?] - and I was surprised to feel that they were also `Hot` when the Heater was set on 1 KW - ?


Some Members will recognise that I am a Heating Engineer - from My previous Posts on the Forum - So I don`t have the Electrical Knowledge to know what could cause this on the Electrical Installation.

I have told my relative to not use the Heater and I am going to take another 3 KW Heater to Her Home to check whether the Plug Pins also get Hot - before I advise that this is checked out by an Electrician.


What could be causing this ? [I hope that it is the Heater ?] - I feel that the Pins get Too Hot for this to be `Normal` ?

I would be grateful if Members can suggest possible causes - I will NOT be trying to rectify this - any Testing or Remedial Work will be carried out by an Electrician - I would just like to know what the cause could be so that I can tell My relative and probably help Her to arrange an Electrician.


Regards,


Chris

 

[Rockingit]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

Chris, you'll more than likely find that it's heat transfer from the PLUG itself, and in turn that will be because 1) the internal connections aren't that great and 2) 3kw = almost 13A....... ANY plug will get hot after an extended run flat out (an exception being the MK chunky plugs!).

 

[Guitarist]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

As Rockingit says, the connections in the plug itself may be poor, including strands broken off where they go under the screws. Check the terminations by all means, but it is quite normal for heater plugs to get warm, though how yours compares to what I would consider normal is hard to say over the internet

 

[chris murphy]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

Chris, you'll more than likely find that it's heat transfer from the PLUG itself, and in turn that will be because 1) the internal connections aren't that great and 2) 3kw = almost 13A....... ANY plug will get hot after an extended run flat out (an exception being the MK chunky plugs!).

"Hello Rockingit",

Thanks for replying so quickly - I did look at the wiring to the Plug which was definitely not the original `sealed` Manufacturers Plug - it did not look badly terminated - but I did not actually take out the wires to look at the copper `strands` etc. as there was no suitable Screwdriver available.

I will definitely check out the wires when I revisit - which will be soon as My relative wants to be able to have use of a Heater sometimes at Night.

Would you expect what You described to still happen when running on the 1 KW setting ?


Thanks for your help with this - I really appreciate it - hopefully it will be as `simple` to fix as you suggest - I will obviously tackle rewiring the Plug [I stated that I would NOT attempt to Fix the problem] - saving My elderly relative the cost of an Electrician.


Regards,


Chris

 

[chris murphy]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

As Rockingit says, the connections in the plug itself may be poor, including strands broken off where they go under the screws. Check the terminations by all means, but it is quite normal for heater plugs to get warm, though how yours compares to what I would consider normal is hard to say over the internet

"Hello Guitarist",


Thanks for your reply - I was writing My reply to Rockingit when You posted it.

The Plug `Pins` do get Hot - not just warm - I know what You mean about judging Heat - I can hold the Pins but they would not have to get much Hotter before I could not - so they are quite Hot.

Also quite Hot on the 1 KW setting - which definitely surprised Me - BUT I have not used Electric Heaters / Fan Heaters for Years so I had no reference point / memory of the Plugs / Plug Pins getting Hot.


Thanks again,


Chris

 

[Strima]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

To be on the safe side it would be worth getting the appliance PAT tested to be sure.

Have you searched the net for the make and model of the heater to see if any problems have been mentioned or even a manufacturers recall?

 

[Guitarist]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

One other point to consider is cable size. I've noticed a trend towards 1.25mm cable on 3kw equipment recently, as opposed to 1.5mm, and it does tend to make the whole plug/cable assembly run hotter.

 

[chris murphy]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

To be on the safe side it would be worth getting the appliance PAT tested to be sure.

Have you searched the net for the make and model of the heater to see if any problems have been mentioned or even a manufacturers recall?

"Hello Strima",

Thanks for your suggestion about the PAT Testing - in general this is good advice - but I have advised My relative to buy a New Heater - whatever the outcome of the possible Electrical Problem:

There was no manufacturers name on the Heater which looks like it is quite old - I have recommended that My relative purchase a New Dimplex Fanned Convector Heater - or similar `Good Brand` Heater.

Even If I can just rewire the Plug and perhaps this will cause less Heat to be produced from within the Plug - I feel that a New Heater would be advisable.

I mentioned that She could get a Thermostatically Controlled / Timer Controlled Dimplex Fanned Convector which She was very interested in.


I am glad to find out that this is probably NOT a Fault with the Electrical Installation.


Thanks again for your interest and good suggestion.


Regards,


Chris

 

[chris murphy]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

One other point to consider is cable size. I've noticed a trend towards 1.25mm cable on 3kw equipment recently, as opposed to 1.5mm, and it does tend to make the whole plug/cable assembly run hotter.

"Hello again Guitarist",

I noticed that the Cable looked smaller than I have seen on more Modern Heaters - I would be fairly sure that it was NOT 1.5mm - probably 1.25mm.

I take it that this causes Heat to be produced because of the Current `Drawn` from the 2.5mm T&E into the 1.25 Cores - ? [I know that this is a simplistic view of it]

Thanks again.


Chris

 

[Simlec]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

Is this thread a wind up???
Every single plug top fan heater makes the plug warm/hot!!!
you say your an engineer!?!

 

[Des 56]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

Chris is a heating engineer, who has been very helpful to this forum with the skills of his own trade, long may he feel welcome and be assisted on this forum

 

[chris murphy]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

Is this thread a wind up???
Every single plug top fan heater makes the plug warm/hot!!!
you say your an engineer!?!

"Hello Simlec",

I hope that this will not be the start of Insults.


I am describing the fact that the Plug Pins get HOT - not just warm - something that YOU knew about when you were an apprentice is not necessarily known to other Trades / Professions - and I repeat these Pins are much Hotter than I would have expected them to be in `Normal Use`.

I have now been advised by the Helpful Members who have responded to what I asked about what is probably causing the Heating Up.

If You read My original and follow up Posts you would see that I was visiting a relative when this was mentioned to Me - You might have had Electrical Screwdrivers in the Car when visiting people - But I did not and therefore I could not check the terminations / strands of the wires - I just opened the Plug [with a Dinner knife which is all that She had] and looked at the wires - they seemed to be O.K. - but there could easily have strands missing.


I simply would NOT expect to feel the Pins of an Electrical Plug were HOT - including when the Heater was set at 1 KW - which is why I asked the Experts on this Forum.


Chris

 

[chris murphy]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

Chris is a heating engineer, who has been very helpful to this forum with the skills of his own trade, long may he feel welcome and be assisted on this forum

"Hello Des 56",

Thank You very much for your comments - I really appreciate it - and I do feel Welcome on the Forum - as You mention I try to only post replies / advice about My own Trade - Heating / Plumbing & Gas Installations - even then I would not presume to advise on the Electrical side of Heating Controls etc.


Regards,


Chris

 

[Rockingit]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

Chris - if it's still running as hot on a 1kW setting as a 3kW then I'd suggest there's either a fault in the plug wiring or in the appliance itself.......but as you've recommended replacing it anyway then both these possibilities will be dealt with!

nb - it's not the change in diameter from 2.5 to 1.25 that causes the heat, it's simply the fact that a smaller cross section cable has a higher resistance, so a little bit of ohms law (V/R=I) and you can see that the 'lost' energy gets dissipated as heat.

 

[chris murphy]

Re: 3 KW fan heater plug `Pins` are Hot when pulled out of socket - What causes thi

Chris - if it's still running as hot on a 1kW setting as a 3kW then I'd suggest there's either a fault in the plug wiring or in the appliance itself.......but as you've recommended replacing it anyway then both these possibilities will be dealt with!

nb - it's not the change in diameter from 2.5 to 1.25 that causes the heat, it's simply the fact that a smaller cross section cable has a higher resistance, so a little bit of ohms law (V/R=I) and you can see that the 'lost' energy gets dissipated as heat.

"Hello again Rockingit",

Thanks for replying - that is basically what I meant but My explanation was lacking in the correct terminology - the Power is `Flowing` easier through the 2.5mm and then while being `Drawn` through the smaller 1.25mm causes Heat to be produced.

Obviously the different `Resistance` as you stated is the correct / professional way to explain this - "Thanks".


Chris.