† † † Buy Cheap Sockets and DIE! † † †

[quelquod]

I think that the relatively standard 13A rating in double mains sockets hasn't been widely publicised and certainly isn't commonly known. As a matter of interest I recall pointing this out in a thread on the old board some years back where it was met with surprise.

On the up side most (or certainly most reputable) makes seem to have a great deal of margin and I'd offer the opinion that I've seen about as many single sockets which have expired as double, and single sockets these days much rarer. The main diseases seem to be poor connections at the plug connections due to loss of springiness and poor connections to the cabling caused by the copper's ductility rather than internal failures. I've long lost count of the number of sockets which just came away from their wiring when unscrewed!

[csearle]

I think that the relatively standard 13A rating in double mains sockets hasn't been widely publicised and certainly isn't commonly known. As a matter of interest I recall pointing this out in a thread on the old board some years back where it was met with surprise.

On the up side most (or certainly most reputable) makes seem to have a great deal of margin and I'd offer the opinion that I've seen about as many single sockets which have expired as double, and single sockets these days much rarer. The main diseases seem to be poor connections at the plug connections due to loss of springiness and poor connections to the cabling caused by the copper's ductility rather than internal failures. I've long lost count of the number of sockets which just came away from their wiring when unscrewed!

Yes well of course the whole concept of terminals screwing down onto a ductile material then expecting the tension to be maintained from there on in is flawed.

Also, when testing the Earth Fault Loop Impedance of sockets, both brand new and old, it is noteworthy how the results can vary after a simple wiggle of the tester's plug within the socket outlet. Often only realised by getting a result out of kilter with sockets on the same final circuit.

C.

[jfgw]

As far as I've been taught (never actually dismantled one) the shaver points in this country offer safety precisely by not Earthing the centre point of the secondary winding*.

I have just 500V insulation-tested an old Delta-branded shaver socket. I measured the resistance between each winding and the earth terminal, and between the two windings. All readings were greater than 1000 Megohms.

Julian F. G. W.

[richlist]

Julian, are you talking English ?....I recognise some of the words but this must be that electrical dialect often spoken by electricians which the rest of us just can't quite interpret.

[csearle]

Julian, are you talking English ?....I recognise some of the words but this must be that electrical dialect often spoken by electricians which the rest of us just can't quite interpret.

He is. I expect he'll enjoy explaining it. C.

[dspp]

Makes perfect sense to those who have done proper stuff.
- dspp

[quelquod]

As far as I've been taught (never actually dismantled one) the shaver points in this country offer safety precisely by not Earthing the centre point of the secondary winding*.

I have just 500V insulation-tested an old Delta-branded shaver socket. I measured the resistance between each winding and the earth terminal, and between the two windings. All readings were greater than 1000 Megohms.

Julian F. G. W.

He means that (at the least as an absolute minimum) what csearle posted is the case. The shaver point is floated (isolated) from earth.

[jfgw]

Personally I suspect that this socket is a counterfeit one. There was a large concern in the mid 90's of counterfeits making their way onto the UK market. Why anyone should counterfeit such devices escapes me, but evidence shows that they have and continue to do so.

An electrician colleague of mine saw one at the moment it caught fire whilst being overloaded.

Could that one have been counterfeit? I thought they were meant to be fire retardant.

The brown/black moulded plastic component on the back of the socket detailed in the OP is marked FRPP (Flame Retardant Polypropylene). If I use a lighter to apply a flame to it, it melts but does not catch fire. If I apply a flame to the white fascia, it singes but does not catch fire.

Mind you the majority that I've found with two heavy duty machines plugged in have suffered no visible consequences. I imagine they were simply well made.

Reading elsewhere, it seems that they are tested at 14A + 6A. Although they are rated at 13A total, there is a considerable safety margin.

Julian F. G. W.