Under floor heating system problem

[JohnW2]

Perhaps they know it is safer not to earth it otherwise there is no point going to the trouble of making it Class II.

Maybe - who knows what they think, know, or think they know?! In terms of possible faults arising within the equipment itself (possibly in conjunction with other faults), it is surely 'safer' ('belts and braces') for it to be double insulated and to have an earthed outer metallic case, rather than to have just one of those protective measures? The downsides of earthing that case (if it's Class II) are all about the safety of the environment in general. Of course, if it's Class I, one has no choice but to earth the case, and the 'reduced safety of the environment' is then unavoidable (but clearly not regarded as 'unacceptable', since it is required!).

As Simon has said, I suspect that the real truth is that what we are seeing is probably a perpetuation of a practice which was initially based upon a misunderstanding of the regulatory requirements. The same quite probably goes for "3-pole isolators" and 3A fuses for extractor fans.

If I have a moment with nothing better to so, I might try asking some of these manufacturers, but, if I do, I will not be holding my breath for sensible/useful answers!

Kind Regards, John

 

[EFLImpudence]

Perhaps they know it is safer not to earth it otherwise there is no point going to the trouble of making it Class II.

Maybe - who knows what they think, know, or think they know?! In terms of possible faults arising within the equipment itself (possibly in conjunction with other faults), it is surely 'safer' ('belts and braces') for it to be double insulated and to have an earthed outer metallic case, rather than to have just one of those protective measures? The downsides of earthing that case (if it's Class II) are all about the safety of the environment in general. Of course, if it's Class I, one has no choice but to earth the case, and the 'reduced safety of the environment' is then unavoidable (but clearly not regarded as 'unacceptable', since it is required!).

Oh dear.

NO - braces involve a danger of strangulation so if we can do without them, as with double belted, then we should.


I give up.

 

[JohnW2]

Oh dear. NO - braces involve a danger of strangulation so if we can do without them, as with double belted, then we should.

Is it your view that Class I equipment should be 'banned'?

Kind Regards, John

 

[SimonH2]

What situations do you envisage where it would NOT be a good reason NOT to earth it?

Well one I vaguely recall reading a long time ago, back before RCDs and when Wylex rewireable fuseboards were the norm, and when Black and Decker drills were metal with a 3 core flex ... and before I knew much at all about regs.
A use case was cited where someone is working outside in a large garden (or on a farm like we used to do), so strings a few extensions together. The drill develops a L-E fault, but because of the length of the cables, it takes a while to blow the fuse. Until the fuse blows, there's now a potential divider which (assuming live and earth cores are the same CSA as they are in flexes) means the drill body is at something like 120V.

When I look back at some of the things we used to get up to when I were a lad and worked on a local farm, well as I said, I didn't know better back then Not that I realised at the time, but I reckon we had a few "near misses"

I recall we had this very long extension lead - 2 core with a 13A socket on the end. It was a bit perished, and there was barely a yard of it without at least one bit of tape. Sticking out the end of the socket was a lead with a crock clip. I now know what it was for - making a TT earth by clipping it to a water pipe when exporting supplies between buildings. Back then we didn't, and it mostly got clipped to the equipment in use - until it just got clipped off as it was always getting snagged on stuff.

And then there was the water heater in the dairy that we used to get a tingle off. One day I had it unplugged to use the socket and noticed the earth contacts in the (15A) socket were splayed out - so I squeezed them together. Next time we switched the water heater on there was a bang and several elements blew. Good job we were always in green wellies !
Now there's an example of where not touching something earthed was a good idea.

 

[ban-all-sheds]

OK, I'm not going to argue about the semantics - I would say that it is the environment that becomes less safe, rather than the equipment, but there's nothing to be gained by arguing about the words.

Other than disabusing you of the ludicrous notion that it is "the environment" and not the item concerned which has become less safe.

What makes the environment less safe, if you want to say that, is the presence in it of things which are less safe, or more dangerous. Such as a metal bath which has become less safe, or metal shelves which have become less safe, or a metal tool cabinet which has become less safe.

Or any Class II item which has become less safe.