Mixing Cables

[securespark]

Well, I suppose you could say the dictionary definition of "joint" describes the connection of the socket to the back box with screws.

Accepting that means that such an installation would not be compliant with regulation D.29 without the use of a lead.

As for the BS for sockets, I believe the design has always linked at least one screw hole to the earth terminal, even the earliest late 1940's BS1363 sockets I have seen have been built this way.

 

[stillp]

From BS1363 Part 2, 10.2:
"metal parts on, or screws in or through, non-conducting material, and separated from current-carrying parts... ... need not be in effective electrical contact with the earthing socket contact"

A little later it states thatif there is such a connection it shall be of low resistance.

 

[securespark]

Could the screws (connected to the back box) be describes as current-carrying parts?

 

[JohnW2]

Well, I suppose you could say the dictionary definition of "joint" describes the connection of the socket to the back box with screws. Accepting that means that such an installation would not be compliant with regulation D.29 without the use of a lead.

That was obviously what I was suggesting/asking - and it does see to a a possibility.

As for the BS for sockets, I believe the design has always linked at least one screw hole to the earth terminal, even the earliest late 1940's BS1363 sockets I have seen have been built this way.

That's what I had always assumed, and I've certainly never seen a socket that does not work like that - but stillp seems to have caste some doubt as to whether it is actually 'required' by BS1363.

Kind Regards, John

 

[JohnW2]

From BS1363 Part 2, 10.2:
"metal parts on, or screws in or through, non-conducting material, and separated from current-carrying parts... ... need not be in effective electrical contact with the earthing socket contact"
A little later it states thatif there is such a connection it shall be of low resistance.

Do you interpret that as meaning that attaching a socket to a backbox does not have to create electrical continuity between the backbox and the socket's earth contact?

Kind Regards, John

 

[stillp]

From BS1363 Part 2, 10.2:
"metal parts on, or screws in or through, non-conducting material, and separated from current-carrying parts... ... need not be in effective electrical contact with the earthing socket contact"
A little later it states thatif there is such a connection it shall be of low resistance.

Do you interpret that as meaning that attaching a socket to a backbox does not have to create electrical continuity between the backbox and the socket's earth contact?

Kind Regards, John

For an insulated socket, yes, that is what it seems to say.
For a metalclad socket there is a resitance test at 25A, and the resistance shall not exceed 50 milliohms.

 

[stillp]

Could the screws (connected to the back box) be describes as current-carrying parts?

No, when that term is used it means current-carrying in normal service.

 

[JohnW2]

Do you interpret that as meaning that attaching a socket to a backbox does not have to create electrical continuity between the backbox and the socket's earth contact?

For an insulated socket, yes, that is what it seems to say.

Interesting. I suppose that makes it even more surprising that the old regs didn't mention fly-leads. Mind you, even if that's what BS1363 actually 'allows' for insulated sockets, I wonder if any manufacturer has ever produced a socket which does not 'connect' the backbox to the earth contact of the socket?

For a metalclad socket there is a resitance test at 25A, and the resistance shall not exceed 50 milliohms.

That makes sense.

Kind Regards, John

 

[EFLImpudence]

Would this be, as it were, the converse of the over-sleeving of CPCs thread.

Namely, just because the regulations did not specify a fly lead does not mean it does not have to be done, if this is the only way the socket could be satisfactorily earthed.

 

[stillp]

because the regulations did not specify a fly lead does not mean it does not have to be done, if this is the only way the socket could be satisfactorily earthed.

Exactly. The apparent omission in BS 1363 doesn't mean you can get away with not ensuring earth continuity at all outlets.

 

[stillp]

I suspect the OP has long since lost interest, but if you're still listening sparkymonkey, you may run a network cable in the same trunking as the power cable, provided that each cable is insulated for the highest voltage present, so you might need to check the rated insulation voltage of your network cable. See 528.1 (i).

However you really must get the earth continuity of the socket-outlets checked rather than assuming the "council sparky" knows what he's doing.

 

[securespark]

Yes, apologies, I rather got caught up and forgot the original thread...

Maybe Mods could split it off so we can continue to have a good yack about it...?

 

[securespark]

What's bothering me is....if BS 1363 does not require the screwhole to connect to earth, why are all 1363 accessories built that way?

Also, if the 14th intended flyleads, given the way the rest of the book is written, I'm surprised they don't get a mention.

Also, I am surprised that I have found so few conduit installs of that era that do have flyleads, literally one or two in 25+ years!

 

[JohnW2]

Would this be, as it were, the converse of the over-sleeving of CPCs thread. Namely, just because the regulations did not specify a fly lead does not mean it does not have to be done, if this is the only way the socket could be satisfactorily earthed.

I think it does - but that still leaves room for discussion as to whether or not 'satisfactorily earthed' can/could ever be achieved without a fly-lead. As I said before, my personal feeling/intuition is certainly not to rely on something as user-disturbable as the tightness of faceplate screws.

Kind Regards, John

 

[JohnW2]

What's bothering me is....if BS 1363 does not require the screwhole to connect to earth, why are all 1363 accessories built that way?

It is rather surprising, given that manufacturers will usually do anything to restrict cost to what is required to just satisfy a Standard. However, there obviously has never been anything stopping them 'going beyond' what is required by the Standard. Maybe they were more realistic (perhaps even 'public-spirited' in the early days, and then perpetuated thereafter) than the BSI in realising that people may well install without fly-leads?

Also, if the 14th intended flyleads, given the way the rest of the book is written, I'm surprised they don't get a mention.

Yes, from what you've said about the 'style' of the 14th ed., that does seem rather surprising.

Also, I am surprised that I have found so few conduit installs of that era that do have flyleads, literally one or two in 25+ years!

That presumably implies that nearly everyone took the regs 'at their word', and were satisfied that the sockets were 'satisfactorily earthed' without a fly-lead.

Kind Regards, John