very hot 13 amp plugs

[mattysupra]

just to answer a few questions.

1- I have checked the tightness of the grub screws in the socket (was my first thought)

2- There is 4 heaters in total. 2 of one make and 2 of another. (every heater sends the plug hot)

3- No matter which socket i plug them into the plugs get hot.

4- They are all molded plugs

5- i have tried in 4 different ring mains, they have been the only item switched on.

6- They are all twin sockets but only have the heater plugged in them.

 

[JohnW2]

Some of the counterfeit / poor quality items are not cheap to buy, just a few percent cheaper than the genuine items.

Indeed. Not only does that maximise the profits of the purveyors of counterfeit / poor quality items, but it also helps to (obviously inappropriately) 'reassure' purchasers that they are not buying something 'cheap and nasty' or 'too cheap to be true. This all adds to the difficulty in identifying which products one should not be buying.

Kind Regards, John

 

[joe-90]

If you cut a moulded plug off and put your own on - does that negate your warranty?

 

[Jackrae]

OK, I got the semantics wrong. When I referred to the "plug top" I was of course referring to the whole plug. "Plug top" is an historical part of my apprenticeship when we referred to plugs as such. Don't ask me where the expression came from.

 

[EFLImpudence]

It won't negate the warranty but if you are going to complain to the manufacturer I would leave it as is until they have investigated.

Try new socket(s) first.

 

[JohnW2]

If you cut a moulded plug off and put your own on - does that negate your warranty?

Why should it (except for any warranty that the plug may have had!)? Manufacturers will, of course, claim that anything and everything under the sun will invalidate a warranty, but I'd like to think that no sane court or arbitrartor would ever take seriously a claim that changing a plug had any effect on the warranty for the equipment to which it was affected.

Of course, in certain circumstances, changing the fuse in a plug to a higher rating than that supplied/specified by the manufacturer could be argued to invalidate a warranty - but one could do that without changing the plug!

Kind Regards, John

 

[disinfo]

I have a 3kW Honeywell fan heater at work, the plug gets very warm on that, I've not touched the pins because it didn't seem like a good idea.

The sockets in my work area are all metalclad wired in tri-rated singles, last time I inspected the socket there were no signs of over heating.

Next time I'm working back at HQ ill take a look.

P.S the heater is rubbish.

http://www.hygienesuppliesdirect.com/products/prod151880

 

[mattysupra]

I have a 3kW Honeywell fan heater at work, the plug gets very warm on that, I've not touched the pins because it didn't seem like a good idea.

The sockets in my work area are all metalclad wired in tri-rated singles, last time I inspected the socket there were no signs of over heating.

Next time I'm working back at HQ ill take a look.

P.S the heater is rubbish.

http://www.hygienesuppliesdirect.com/products/prod151880[/QUOTE]


Hi,

Thats the one. I didnt touch the pins on purpose. It had just been unplugged and i went to move it grabbing the plug !

Ye, i also think its crap. You seem to get a lot more heat out of a normal domestic fan heater. However if its using 3kw of heating power then i pressume it is putting out the heat? i cant see how it cant do, but like you say it seems crap when stood in front of it.

Another thing i found stupid. I set it on frost stat but the fan always runs? so if i was to leave the building for say 2 weeks holiday and set the heaters to turn on for frost protection i would be paying for the fans to be constantly running.

The temp setting on the front only turns off the heating element and not the fan. O and i left on over night and fan never turned off in case anyone was thinking it was cooling itself down.

 

[JohnW2]

Another thing i found stupid. I set it on frost stat but the fan always runs? so if i was to leave the building for say 2 weeks holiday and set the heaters to turn on for frost protection i would be paying for the fans to be constantly running. The temp setting on the front only turns off the heating element and not the fan. O and i left on over night and fan never turned off in case anyone was thinking it was cooling itself down.

I can't say I've come across that before but, if that behaviour is intentional, it might not be as stupid as one might first think. Having the fan running all the time presumably makes it far more likely that the temperature sensor will 'see' the temperature of the room in general, rather than just in the (perhaps sheltered) vicinity of the heater (or sensor, if remote). For example, in terms of the 'frost stat', with no fan running, one corner of the room might be well below freezing, even though the sensor/thermostat was not seeing a low enough temperature to activate the heater. However, that's pure speculation!

Kind Regards, John

 

[disinfo]

To be honest, for me to call it rubbish is probably a bit unfair.

Our workshop is miserably cold in the winter (not great in the summer either)

Its also a big wide open space, I bet I'd be a lot more impressed if I ran the heater in a small enclosed room.

I bet when I have mine on the full setting as I always do the thermostat never gets to temperature just because of how cold our building is, so it will be running at full load current for most of the time.

On the plus side, I've had it for a couple of years now and nothing has burned up yet, they are fairly decent metalclad sockets though (GET i think)

 

[SimonH2]

Another thing i found stupid. I set it on frost stat but the fan always runs? so if i was to leave the building for say 2 weeks holiday and set the heaters to turn on for frost protection i would be paying for the fans to be constantly running.

If you measure it, you'll probably find the fan doesn't take all that much power - and if the weather is cold enough that you are worried about frost, then it's probably insignificant compared with the heating load.

As others have said, you need the fan running to allow the thermostat to sense real air temperature, not the temperature inside the unit (which would be warm if the heater has been on recently). Moving air will also minimise the risk of freezing as it will disturb pockets of air that might be locally colder then elsewhere.
I suppose if the manufacturer had been "sophisticated" then they could have made the fan run at a lower speed when the heater was off, but I suspect they were designed down to a budget.

 

[westie101]

So in another thread there is a discussion about cable operating temperatures and that they can safely operate up to temperatures as high as 90C.

Now I'm showing my ignorance here, but wonder what the maximum permissible operating temperature of a 13A plug/socket combination is and whether the issue of warm plugs actually falls into the permitted range?

I would suggest it's fair to say that there are a lot of folk out there that are unaware that a cable or piece of equipment being warm is actually acceptable which leads to a lot of "false alarms"

 

[mattysupra]

hi everyone.

I have had a look at a socket and i cant find a make. It has all the BS numbers etc inside but no make. I 'think' they may be B&Q sockets as i recall the sparky saying he purchased a load of CU units and sockets from B&Q at a great price.

Anyway, some of the sockets are metal (old sockets that was reused. I say old but the building is only 12 months old) and these also get hot.

As for the plastic sockets, one of them cracked up the center of the pins today ! Presume due to the heat ?

 

[JohnW2]

So in another thread there is a discussion about cable operating temperatures and that they can safely operate up to temperatures as high as 90C.

Only some cables. Those commonly used in domestic installations can only operate up to 70 °C.

Now I'm showing my ignorance here, but wonder what the maximum permissible operating temperature of a 13A plug/socket combination is and whether the issue of warm plugs actually falls into the permitted range?

BS1363 includes a temperature rise test for plugs/sockets. but I forget what the acceptable temperature rise (at 20A through a double socket) is. I'm sure someone will be able to remind us.

I would suggest it's fair to say that there are a lot of folk out there that are unaware that a cable or piece of equipment being warm is actually acceptable which leads to a lot of "false alarms"

Up to a point, you're obviously right - any passage of current along a conductor will generate some heat. However, there is warm and warm (or hot!). I have to say that I've alays been surprised/confused by the tabulated maximum CCC figures in BS7671. Each table relates to a specified ambient temperature (usually 30 °C) and 'conductor operating temperature', and that latter temperature is 70 °C for most 'ordinary/ common' cables. The implication seems to be that, if run at maximum CCC for a given installation method, the conductor temperature will, indeed, rise to 70 °C. However, that is very hot (too hot to touch), and one would imagine that the outside of, say, T+E cable would eventually get 'pretty hot' if the conductor temperature were a constant 70°C. Admittedly,domestic fixed wiring is rarely run at, or even close to, its CCC, but I have never personally felt any such wiring which is more than 'slightly warm', and would probably be alarmed if it felt 'hot'. To take an example, do the conductors of 2.5mm T+E 'clipped direct' really reach a temp of 70 °C with 27A flowing?

Kind Regards, John

 

[EFLImpudence]

do the conductors of 2.5mm T+E 'clipped direct' really reach a temp of 70 °C with 27A flowing?

They can't do, can they?

The 27A would have to be the absolute maximum CCC but, as we have been discussing, a significant safety margin is built in.