13 amp plug overheating

[JohnW2]

Yes although it seems to take some time for the fuse to blow ...

I think something which needs to be borne in mind is that to blow a 13A plug fuse, purely, as the result of excessive current passing through it, requires at least something like 22A (about 5 kW at 230V) to flow through it for an appreciable period of time.

However, if the fuse is appreciably heated by some external cause (e.g. due to poor connections/contact, it may blow with a much lower amount of current flow through it.

 

[johnbuckley]

Are the fuses she is using as replacements a good quality brand, IE not cheap imports?

They're unbranded and BS1362 certified, prob a screwfix/toolstation product.

 

[mattylad]

The plug from Screwfix ifs fine for use, I use them when replacing plugs on items and they are generally better than what was on it in the first place.

I'm a little confused about where exactly this plug is? is it on the heater or on the cable that supplies the van?
If it's on the heater, does it also get as hot when plugged in at home?
If not also check the the terminals in the back of the socket in the van for tightness.

Perhaps we need to see a photo of the inside of the plug as has been requesting ISTR?
Also a photo of the heater and another of the heaters data plate.

 

[johnbuckley]

The plug from Screwfix ifs fine for use, I use them when replacing plugs on items and they are generally better than what was on it in the first place.

I'm a little confused about where exactly this plug is? is it on the heater or on the cable that supplies the van?
If it's on the heater, does it also get as hot when plugged in at home?
If not also check the the terminals in the back of the socket in the van for tightness.

Perhaps we need to see a photo of the inside of the plug as has been requesting ISTR?
Also a photo of the heater and another of the heaters data plate.

Thanks for that. The plug is on the 16 amp lead that supplies the van, it has the standard 16 amp round pin socket that plugs into the van on one end and 13 amp 3 pin socket that plugs into any domestic 240 volt outlet on the other end.
I will get the pics on Thursday, I'm not local and my daughter is away until then.
The heater has a standard 3 pin 13 amp plug which is plugged in inside the van and there has been no problem with that.
Never thought to check the van socket for tightness.

 

[ericmark]

So you are talking about one of these which is supplying the van 22 amp consumer unit with a 13 amp fuse, and one wonders why it gets hot? I have seen these where the 16 amp feeds the 6 amp so total 16 amp, but in the main they rely on the caravan site having an overload at 16 amp and using a lead like this which should be 2.5 mm² and no more than 25 meters long. However the bit

708.553.1.14 Socket-outlet protective conductors shall not be connected to any PEN conductor of the electricity supply. For a TN-C-S system, for a supply with a PEN conductor the protective conductor of each socket-outlet shall be connected to an earth electrode and shall comply with the requirements of Regulation 411.5 for a TT system.

is the main bit, most homes have a TN-C-S supply, so she would need to not use the earth and drive a stake into the ground instead. That is clearly not going to happen, so only option is a generator built into the van.

 

[JohnW2]

.... the van 22 amp consumer unit with a 13 amp fuse, and one wonders why it gets hot?

Well, yes, if (as we have been told) the total load is not much over 10A, I would wonder, wouldn't you?

Adding up the MCB ratings, in the way that you've done, is obviously no indicator of the size of the actual load - I;'ve just looked at the ndearest of myt CU's, and the MCBs add up to 152A, but that doesn't mean that the 60A DNO fuse protecting it gets particularly hot

 

[Harry Bloomfield]

So you are talking about one of these which is supplying the van 22 amp consumer unit with a 13 amp fuse, and one wonders why it gets hot?

Eric, you are assuming rather a lot. The OP is only talking about a load of 2.4Kw, not the 22amp you mention. If correct, the 2.4Kw should not be that much of an issue, fed from a 13amp socket.

 

[ericmark]

Eric, you are assuming rather a lot. The OP is only talking about a load of 2.4Kw, not the 22amp you mention. If correct, the 2.4Kw should not be that much of an issue, fed from a 13amp socket.

But it seems it is a van, so how does one get a safe supply? About the only supply one can get which has protection for loss of PEN is for an EV.

 

[JohnW2]

But it seems it is a van, so how does one get a safe supply? About the only supply one can get which has protection for loss of PEN is for an EV.

That's a totally different issue/question from the one you were addressing (when you implied that there was a problem with a 13A plug supplying a CU's whose MCBs 'added up to' 22A).

 

[johnbuckley]

Eric, you are assuming rather a lot. The OP is only talking about a load of 2.4Kw, not the 22amp you mention. If correct, the 2.4Kw should not be that much of an issue, fed from a 13amp socket.

Yes that's absolutely correct, the only current draw at any one time is use of the 2400w appliance and 35w total led lights.

 

[mattylad]

So, if you draw 2400w+ through a 13A plug/socket constantly it will get hot, no if's buts or maybe - it's going to get hot.
That is because the plug/socket interface is not really designed to take constant higher currents.

This is why your 16A lead should really have a 16A blue plug on it also, it's designed for a higher load.

I used to make hot cupboards, when we had 2KW ones that had to have a the same plug as your using they got stinking hot on test.

Turn the heater in the blower down.

BTW, what is the heater/blower?
Got a picture of it?

 

[JohnW2]

So, if you draw 2400w+ through a 13A plug/socket constantly it will get hot, no if's buts or maybe - it's going to get hot.

That depends upon what you mean by 'hot'. BS1363 requires plugs to pass a temperature rise test, requiring a temp (with 20° ambient) no greater than 52° for terminals and external surfaces, and no greater than 37° for some internal parts, with a continuous current of 14A.

That is because the plug/socket interface is not really designed to take constant higher currents.

The BS1363 temp rise test involves 14A for at least 4 hours continuous.

I'm no authority on this, but how long does it take to dry a dog, I wonder?

 

[Harry Bloomfield]

That depends upon what you mean by 'hot'. BS1363 requires plugs to pass a temperature rise test, requiring a temp (with 20° ambient) no greater than 52° for terminals and external surfaces, and no greater than 37° for some internal parts, with a continuous current of 14A.

The BS1363 temp rise test involves 14A for at least 4 hours continuous.

I'm no authority on this, but how long does it take to dry a dog, I wonder?

A new socket, a new plug, both expertly fitted, but give them a few years of wear and tear, and inexpert fitting.

 

[JohnW2]

A new socket, a new plug, both expertly fitted, but give them a few years of wear and tear, and inexpert fitting.

Sure, but it was seemingly being suggested that it was inevitable that a plug would get hot whilst carrying 10-11A 'constantly, would inevitably 'get hot'(presumably even when brand new and 'expertly fitted') "....because the plug/socket interface is not really designed to take constant higher currents.".

In terms of compliance (when new) of plugs with BS1373, sockets don't come into the equation, since the test does not involve a socket (sockets are tested separately, and have their own, similar, temp rise test.

 

[Harry Bloomfield]

Sure, but it was seemingly being suggested that it was inevitable that a plug would get hot whilst carrying 10-11A 'constantly, would inevitably 'get hot'(presumably even when brand new and 'expertly fitted') "....because the plug/socket interface is not really designed to take constant higher currents.".

I would not call it 'inevitable', but I am always wary on the rare occasions I do plug in appliances which draw a higher current, via a 13amp plug and socket, for an extended period of time.