Supplementary bonding?

[odawire]

Met someone the other day, he told me he was a lecturer teaching electrical installation at the local collage, he said that if you have main water and gas bonded you don't need any supplementary bonding regardless of whether you have RCD protection or not. I didn't want to argue with him too much as he is a teacher but I was pretty sure that it only applies if all circuits are RCD protected? Is this some new rule I've missed?

 

[stigwart]

Jesus Christ, where do I start?

You are confusing equipotential bonding with supplementary bonding...that's bad enough. But the R1 + R2 for a RFC comment just beggars belief!

Give up before you kill someone!

Wind your neck in, I was stating the value to be remembered for certain applications, you might remember it now...

 

[Geoffsd]

And that has what to do with supplementary bonding?

 

[stigwart]

When testing continuity between extraneous conductive parts and c.p.c's in the bathroom it should not exceed 0.05 ohms for f@&ks sake!

 

[telectrix]

rubbish! if the cpc of a circuit in a bathroom has a resistance of >0.05 ohms, how would you achieve 0.05 between ext. metalwork and the cpc?

 

[stigwart]

Wait for it, with supplementary bonding!

 

[Geoffsd]

When testing continuity between extraneous conductive parts and c.p.c's in the bathroom it should not exceed 0.05 ohms

How do you think that is possible?

0.05Ω is 3 metres of 1mm².

 

[telectrix]

supp. bonding would only get you 0.05 between ext. pipes, unless you added supp. bonding from fittings to pipes. look good, a few yards of 4mm or 6mm gn/y cable on the tiles.

 

[Guitarist]

I think that a few people actually need to read the regs on here before discounting the need for RCD protection without supplementary bonding.... Figures have absolutely nothing to do with it.
Tell you what, as I'm in a good mood tonight... 701.415.2

 

[bartkusal]

This thread just gon ---- up, all over the place. 1667 ohms stable not stable, 0.05 ohms and rings, etc. I just got dizzy with no beer. the only number you need to know with sup bond is 23 kohm, that's about it.

 

[Deleted member 9648]

Amazing amount of mis-information posted on this thread.
The effectiveness of the connection of ECP's in a bathroom/shower room to the MET/main bonding may be determined by the application of 415.2.2.
Which effectively means where a 30ma RCD is in place a continuity reading of <1667 ohms between CP's and ECP's within the location = satisfactory supplementary bonding.
For a 6a type B mcb a continuity reading of <1.66 ohms = satisfactory supplementary bonding.

 

[shanky887614]

This thread just gon ---- up, all over the place. 1667 ohms stable not stable, 0.05 ohms and rings, etc. I just got dizzy with no beer. the only number you need to know with sup bond is 23 kohm, that's about it.

there getting there terminology confused.

the ring guy i think is trying to say, 0.5 between sockets on same rfc

 

[stigwart]

This thread just gon ---- up, all over the place. 1667 ohms stable not stable, 0.05 ohms and rings, etc. I just got dizzy with no beer. the only number you need to know with sup bond is 23 kohm, that's about it.

Yeah your right, thats taking the human body resistance into account at 1000ohms and 230v supply.
And thats the measurement from the bathroom zones to the MET.
I was taught the 0.05 ohm measurement between PE terminals and extraneous conductive parts in the bathroom.
I will try and find that in writing (I hope I can for my sake, its like a bear pit around here!!)
and post it.
In my inspection and test assessments they made a big deal of this figure not being exceeded.

 

[Amp David]

I didn't explain myself very well, all the readings on a true ring should be the same within 0.05 ohms so for example 0.45 on one 0.50 on another.

I understood what you meant, just some of us are simple and can't read a post and actually decipher whats been posted sometimes.

 

[Amp David]

Supp bonding and the good old 50 volt touch voltage!

R ≤ 50 v / Ia

Ia for RCD would be I delta n and OCPD would be the current cause the said device to trip within 5s.

 

[bartkusal]

Yeah your right, thats taking the human body resistance into account at 1000ohms and 230v supply.
And thats the measurement from the bathroom zones to the MET.
I was taught the 0.05 ohm measurement between PE terminals and extraneous conductive parts in the bathroom.
I will try and find that in writing (I hope I can for my sake, its like a bear pit around here!!)
and post it.
In my inspection and test assessments they made a big deal of this figure not being exceeded.

I think your figure of 0.05 ohms came from guidence( and only guidence), that when testing continuity of your protective bonding conductors, even though you just put a tick in box on your certificate it "SHOULD" be under 0.05 ohms, which is derived from formula too, can not think exactly from my head at this min, and us I said it is only guidence, dont remember seeing this figure anywhere in the regs book.