"Do not use an extension lead!"

[ericmark]

Ah, I see. I misunderstood. Like those sockets that can take American and Australian plugs, for example.

Yep, Hong Kong does not seem to have a standard socket, they use all sorts. But some things stricter than here, this is before take over, I had to show my radio licence to buy a transceiver, here anyone can buy them, but need a licence to use them, all best VR2ZEP

 

[JohnW2]

The receptacles in the sockets on ready made extension lead often have the minimum area of contact with the pins in the appliance plug, This results in poor electrical contact which causes heating of receptacle and pin.

Are you talking about the 'minimum area' as required to satisfy the relevant product Standard?

If so, are you suggesting that the required 'minimum' is inadequate - i.e. that the Standard is 'wrong'?

 

[ericmark]

Are you talking about the 'minimum area' as required to satisfy the relevant product Standard?

If so, are you suggesting that the required 'minimum' is inadequate - i.e. that the Standard is 'wrong'?

I was also considering that. Years ago the plug had brass pins which could assist in transferring the heat of the fuse to the socket, so increasing the surface area to dissipate the heat from. The use of insulation on the pins, has resulted in less heat being transferred to the socket, as to if this is good or bad not so sure, but items which use the maximum of 3 kW for an extended time, like immersion heaters, tend to use a fused connection unit (FCU) and even back in 1954 when dads house was built and we did have full size pins, the immersion heater used a 15 amp plug and socket so only fuse was in the fuse box.

However the whole idea of the ring final was that we could heat the home with electric, when we finally did start using electric however we did not fit 13 amp plugs and sockets to the storage radiators. But I have used electric heaters, be it a fan heater, to an oil filled radiator with thermostatic control for years, and if good quality plugs and sockets are used, there seems to be no problem.

It does not really matter if the plug and socket are inline, or fixed to the wall, they should take the load, and undersized flex is not going to cause the plug and socket to over heat, but the problem is deciding if the plug and socket is good quality or poor. Be it kite mark or BS making they can all be faked, and likely the biggest problem is the fake fuse which can over heat the plug. But smash the fuse to see it is a proper sand filled fuse, and it can not longer be used, so we have no option but take a chance.

 

[Harry Bloomfield]

Normally, if you use an extension lead on a coil and it’s a high demand unit that it’s powering, the coil could heat up. You are supposed to uncoil the whole length.

Besides which, some extension leads can include some undersized conductors. There is not usually a problem using an extension, always providing it is properly uncoiled, the conductors are adequate, and it includes a quality plug and socket.

 

[Harry Bloomfield]

If so, are you suggesting that the required 'minimum' is inadequate - i.e. that the Standard is 'wrong'?

IMHO- yes! I am always wary of running a 13amp plug or socket, close to it's 13amp limit, for an extended amount of time. .

 

[JohnW2]

IMHO- yes! I am always wary of running a 13amp plug or socket, close to it's 13amp limit, for an extended amount of time. .

Yes, although I've experienced, or been aware,of very little of it personally, we do hear a good few stories of BS1363 sockets suffering from high loads, suggesting that one which 'just satisfy the requirements of BS1363' are really 'not fit for purpose'.

If so, it seems strange that the situation has been allowed to persist. It's well over 70 years (not much short of 80) since BS1363 was born and, as far as I can make out, its requirements have changed very little during that period - implying that 'they' don't think that an increase in the 'minimum requirements' is necessary.

Kind Regards,John

 

[Harry Bloomfield]

If so, it seems strange that the situation has been allowed to persist. It's well over 70 years (not much short of 80) since BS1363 was born and, as far as I can make out, its requirements have changed very little during that period - implying that 'they' don't think that an increase in the 'minimum requirements' is necessary.

The manufacturers used to make robust 13amp plugs and sockets, which well exceeded the standard. Now, they just meet the standard. As Eric suggested, I think the sleeved pins have also compounded the heat dissipation issues.

 

[JohnW2]

The manufacturers used to make robust 13amp plugs and sockets, which well exceeded the standard. Now, they just meet the standard. As Eric suggested,

That's very probably true, but as I have said/implied, the 'minimum requirements' of the Standard really should be enough to render a product 'fit' for purpose - after all, what the point in having a Standard if products are only satisfactory if they exceed the requirements of the Standard? My father, who was a Standards Engineer in the latter part of his career, would probably be turning in his grave at such a suggestion!

I think the sleeved pins have also compounded the heat dissipation issues.

That could well be true - but, even now the pins are sleeved, they still have to pass the same temperature rise test as they always have had to pass - so,again, it seems to be the case that the products have really only ever been 'satisfactory' if they exceeded the requirements of the Standard.

Kind Regards, John

 

[blup]

I have thought that, although we have no claim on B&Q, we could cut off the damaged plug and attach another and continue to use the fire. However, doing this would also invalidate the warranty, I assume, and the electrician also advised against doing this,
Any advice or comments, and even criticisms! are very welcome.

Use a length of 1.5mm2 heat resistant flex and re wire the heater plus, crimping the ends, plus new 13A plug. Or better still just extend the circuit and add a new socket. Bin the extension cable.

 

[Harry Bloomfield]

That's very probably true, but as I have said/implied, the 'minimum requirements' of the Standard really should be enough to render a product 'fit' for purpose - after all, what the point in having a Standard if products are only satisfactory if they exceed the requirements of the Standard? My father, who was a Standards Engineer in the latter part of his career, would probably be turning in his grave at such a suggestion!

Even so, I would not be comfortable, leaving an appliance unattended, which drew close to the full 13amps, through a plug and socket. I have seen far too many of them damaged.

 

[JohnW2]

Even so, I would not be comfortable, leaving an appliance unattended, which drew close to the full 13amps, through a plug and socket. I have seen far too many of them damaged.

Indeed. As I said, even though I've had no particularly nasty experiences myself, we see/hear plenty of such stories - which is why I would say that (assuming the accessories concerned have been 'BS1363-compliant' there would appear to be something very wrong with the 'minimum' requirements' of the Standard.

As I've said, the argument that the situation used to be better because accessories wee being manufactured so as to appreciably exceed the required 'minimum standard' seems to make nonsense of the concept of having a Standard !

Kind Regards, John

 

[JBR]

Use a length of 1.5mm2 heat resistant flex and re wire the heater plus, crimping the ends, plus new 13A plug. Or better still just extend the circuit and add a new socket. Bin the extension cable.

Thank you. Yes, the extension lead will be binned, as the original plug of the fire is welded in it!
There is no damage to the remainder of the lead of the fire, so I plan to attach a new plug of good quality.
The electrician who examined it all will install a new wall socket closer to the fire, so there is no need now for an extension lead.

 

[JBR]

Even so, I would not be comfortable, leaving an appliance unattended, which drew close to the full 13amps, through a plug and socket. I have seen far too many of them damaged.

Good advice. The wife tells me that her mother seems to leave the fire on for extended lengths of time. She (mother in law) is going a bit doolally into the bargain so, if it is possible, we could limit its output (if possible) or even replace it with one of lower power.

 

[SUNRAY]

Indeed. As I said, even though I've had no particularly nasty experiences myself, we see/hear plenty of such stories - which is why I would say that (assuming the accessories concerned have been 'BS1363-compliant' there would appear to be something very wrong with the 'minimum' requirements' of the Standard.

As I've said, the argument that the situation used to be better because accessories wee being manufactured so as to appreciably exceed the required 'minimum standard' seems to make nonsense of the concept of having a Standard !

Kind Regards, John

I think it's more a question of longevity.
A sample product is tested to the standard and it passes. → in use something is plugged in and out a few dozen times with the plug not in perfect alignment possibly and the socket contact gets a little bit splayed → a little bit of resistance creeps in and overheating starts occurring → the metal contacts are softened and any spring effect is reduced/negated and more heat is generated.

It doesn't only happen in cheap rubbish, it happens in expensive rubbish too.

This was on a water urn in a school, a new servery extension or tuck shop sort of thing and the spec called for the moulded plug to be replaced with MK, I think this work was done at Easter and failed PAT in summer holiday so 3 months use and probably not unpluged.

 

[JohnW2]

I think it's more a question of longevity. ... A sample product is tested to the standard and it passes. → in use something is plugged in and out a few dozen times with the plug not in perfect alignment possibly and the socket contact gets a little bit splayed → a little bit of resistance creeps in and overheating starts occurring → the metal contacts are softened and any spring effect is reduced/negated and more heat is generated.

Yes, that's often a problem with any product designed for long-term use and potentially susceptible to 'environmental' factors during use. in such situations, the required tests (e.g. as specified in a Standard) should go as far as they can to take that into account - e.g. by not just testing brand new products for very short periods of time.

For example, you would never see a medicine being licensed for long-term administration on the basis of it having been shown to be safe when taken for short periods of time.