Mixing Cables

[RF Lighting]

Not these days. It used to be, but you would require a copper flylead now. Mind you it's been a long time since I've seen anyone using the containment for earth on a new installation.

 

[JohnW2]

Not these days. It used to be, but you would require a copper flylead now. Mind you it's been a long time since I've seen anyone using the containment for earth on a new installation.

Thanks. That's what I suspected.

Kind Regards, John

 

[Adam_151]

Not these days. It used to be, but you would require a copper flylead now.

Are you sure? As far as I know the requirement for a flylead to a front from a containment system acting as a CPC has been a requirement for a long time, although lots of the time it didn't get done.

Anyone able to confirm/deny?

Its unfortunatly a bit of a moot point though if the conduit has been terminated to a m/clad surface accessory without sufficent removal of paint though

 

[RF Lighting]

You may well be right there adam. I just assumed from seeing a lot of older installations with out the fly lead fitted that it did not used to be a requirement.

I've seen a good few duff earths using this system.

 

[securespark]

In my salad days we used to fit glav and B/E conduit without CPC. The conduit was the CPC.

That was a common installation method back then and was allowable as long as a high current test meter was used to check that the joints were impeccably tight and therefore earth continuity was top notch. Later, cpc's were included as a matter of course, meaning it was not necessary to ensure such high integrity earth continuity on the conduit system.

 

[Adam_151]

I've seen a good few duff earths using this system.

Came across it on a bank of sockets in a school once, reckon it was that way since the place was rewired in the early 1980s. Caretaker told me there had been complaints of small shocks from metal classed equipment when I handed him the danger notice

 

[securespark]

You may well be right there adam. I just assumed from seeing a lot of older installations with out the fly lead fitted that it did not used to be a requirement.

I'll go check my 14th Ed....

 

[flyingsparks]

Thanks, thats all I needed to know. I didnt think it sounded like a good idea a but I thought I'd check first.

So you didn't think that was a good Idea but your not bothered about possibly not having your sockets earthed. I know which one i would be more comfortable with! Can we see a photo of inside a socket please?

If its council property what's to lose? Won't cost you anything, will it??

 

[securespark]

Zoom.....I'm back!

This is all I can find about conduits being used as ECC's.

B.98...................If the conduit is used as an earth-continuty conductor, Reg D29 must also be complied with (see also Reg B107).

B.107 Flexible metal conduit shall not be used as the sole means of providing earth continuity......

D.29 Every earth-continuity conductor formed...by...conduits...shall have a resistance not more than twice that of the largest current-carrying conductor of the circuit. All joints shall be mechanically sound, electrically continuous and protected where necessary against corrosion.

K.29
In situations accessible to livestock, a metal...conduit shall not be used as a sole earth-continuity conductor...


I can't find any mention of fly-leads.

 

[JohnW2]

.....
D.29 Every earth-continuity conductor formed...by...conduits...shall have a resistance not more than twice that of the largest current-carrying conductor of the circuit. All joints shall be mechanically sound, electrically continuous and protected where necessary against corrosion.
....
I can't find any mention of fly-leads.

Do you think that reliance on something as user-disturbable as the tightness of faceplate screws would have satisfied the second sentence of D.29 above?

Kind Regards, John

 

[securespark]

Perhaps you could consult the 14th and tell me.

 

[JohnW2]

Perhaps you could consult the 14th and tell me.

Given that you said that there was no explicit mention of fly leads, I was just asking for an opinion! However, the answer is hardly relevent in 2013

Kind Regards, John

 

[securespark]

I just looked to see if there was a specific mention of fly-leads, because it is true that there must be countless installations out there with none, where the earth connection relies on the fixing of the accessory to the back box.

The one criticism of the 14th Ed. (and presumably previous Ed's too) by latter-day IET staff was that it was written very much like an instruction book, giving clear instructions on how to comply with a particular regulation. This, I have been told, made it easy for any T, D or H to pick it up and start work.

From the next edition, the then IEE decided to write in the current style ie, "This is what the regulation requires and it is up to you to decide how to comply with it."

With this in mind, if the regs did not specifically say, " A fly-lead must be connected between the conduit and accessory to ensure earth continuity", then it is quite possible that it has been oft-omitted.

 

[JohnW2]

I just looked to see if there was a specific mention of fly-leads, because it is true that there must be countless installations out there with none, where the earth connection relies on the fixing of the accessory to the back box.

Sure, I realise that.

With this in mind, if the regs did not specifically say, " A fly-lead must be connected between the conduit and accessory to ensure earth continuity", then it is quite possible that it has been oft-omitted.

Agreed - I suppose that's why I asked whether you thought that "...All joints shall be mechanically sound, electrically continuous and ..." in D.29 may have been meant to indicate that a situation without a fly-lead (although not explicitly mentioned) was not acceptable for earth continuity.

I suppose the answer is obvious, but do I take it that BS1363 requires (and has always required) that sockets are manufactured such that fixing them (satisfactorily) to an earthed back box effectively connects the earth to the socket's earth pins(s)?

Do you (or anyone) know when a fly-lead first became explicitly 'required'?

Kind Regards, John

 

[stillp]

I suppose the answer is obvious, but do I take it that BS1363 requires (and has always required) that sockets are manufactured such that fixing them (satisfactorily) to an earthed back box effectively connects the earth to the socket's earth pins(s)?

It seems to require that for metalclad sockets but not for insulated ones.