So do all appliances with BS 4573 plugs, or IEC 60320-1 C2, C8 or C10 receptacles have DP switches?
No testing or MWC/EIC for 'Maintenence'??
- Thread starter JohnW2
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I can't really see how BS7671 could itself become 'a legal document', but the law (written in whatever language) could nevertheless require compliance with it.
As a matter of interest, are their Welsh language versions of Part P and Approved Document P and, if so, have you noticed any 'differences' which have resulted from translation?
Kind Regards, John
Many appliances do have double pole switches. Many don't have switches at all.
It would presumably only be vital for the switch to be double pole if it was regarded as a means of protecting the user from electric shock. Not if it was merely functional switching.
Similarly for fuses/breakers if it's job is to prevent fire in the event of a short to earth it would need to be double pole. If it's merely to reduce the damage in the event of component failure causing a L-N fault then it wouldn't.
It would presumably only be vital for the switch to be double pole if it was regarded as a means of protecting the user from electric shock. Not if it was merely functional switching.
Similarly for fuses/breakers if it's job is to prevent fire in the event of a short to earth it would need to be double pole. If it's merely to reduce the damage in the event of component failure causing a L-N fault then it wouldn't.
True - but I wouldn't have thought that switches which were part of appliance would "be regarded as a means of protecting the user from electric shock", would they?
What you say is obviously true. It's no problem having DP breakers, since the switching of both poles is mechanically linked. However, it is a potential problem with fuses, since their operation cannot be 'linked' - so that DP fusing would present the possibility that only the N one might operate, leaving a theoretical shock hazard.
Kind Regards, John
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On a typical appliance I would expect they would not be but I would also expect exceptions exist.
And then there is stuff that we wouldn't normally consider "appliances" but that nevertheless has a plug on it. For example would people regard the MCB in a portacabin CU as an acceptable way to isolate the lighting (to change an exploded bulb for example) not knowing that someone had pluged it into an adaptor and then into a reversable socket? (outdoor schuko sockets exist and schuko to 60309 adaptors are readilly available so if schuko became common this would not be too unbelivable a scenario)
We have special rules for caravans because it is assumed they will leave the UK but afaict those rules don't apply to other temporary plug-fed installations.
We in britan have built our whole electrical safety infrastructure on the idea that L-N reversals MUST NOT HAPPEN. Violating that rule requires very careful risk assesment.
Having said all that a schuko socket on the factory floor which is RCD protected, where the workers have been told it's only for use to power specific items of equipment, where general socket provision is good and where adaptors to convert schuko to BS1363 or IEC60309 are not readilly available onsite would seem acceptablly low risk to me.
What you say is obviously true. It's no problem having DP breakers, since the switching of both poles is mechanically linked. However, it is a potential problem with fuses, since their operation cannot be 'linked' - so that DP fusing would present the possibility that only the N one might operate, leaving a theoretical shock hazard.
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Yeah neutral fusing will always risk leaving a device in a state where the fault path has been broken but the faulty circuit is still live.
Sure, exceptions exist to most things. One has to make a judgement as to how often they are likely to arise.
Kind Regards, John
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