Equipotential bonding

[ADCG22]

Hi all - my plumber recently installed a new wall mounted tap/shower mixer plus some new pipework. A direct replacement basically.

In doing so he removed a section of copper pipework (and copper elbows) and replaced the copper pipework but used JG Speedfit elbows.

the equipotential bonding clamps weren’t touched (you can just about make these out in the photo - attached before the

first plastic elbow) but do these plastic elbows now compromise the bonding?

Is the metal shower mixer now a potential risk? The pipework is all hidden under the floor and bath.

My thoughts are (and do shoot me down!) are that the mixer is now either electrically isolated or the bonding continuity is still valid. Either way - all good....

please see photo - thanks!

 

[EFLImpudence]

The taps will now be isolated from the metal pipework by the plastic fittings.

However, if the short distance is bridged by the water it could still require the bonding.
I wouldn't think this is likely.

Do you have a multimeter?
If so, set to ohms (Ω) and measure the resistance between the copper on either side of the plastic fittings.

 

[ajohn]

The regs now seem to view that any length of plastic pipe avoids the need for bonding pipework but this applies to where the pipework comes into the house. While it may sound rather odd the idea of bonding there is to protect the house from what may come in via this route. Same with gas pipes.

Hence sink bonding being dropped. I would assume the same applies to showers and baths.

 

[Millwright]

I thought that happened years ago.

 

[EFLImpudence]

I don't think anything has happened. The Physics has always been the same.

The regs now seem to view that any length of plastic pipe avoids the need for bonding pipework but this applies to where the pipework comes into the house. While it may sound rather odd the idea of bonding there is to protect the house from what may come in via this route. Same with gas pipes.

That would be the Main Protective Bonding; that's not what is being queried.
You will think I'm splitting hairs but it's not that the length of plastic pipe (isolating section) avoids the need for MB per se; rather it does not introduce the hazard that necessitates the safety measure.

Hence sink bonding being dropped. I would assume the same applies to showers and baths.

That would be Supplementary Bonding (additional bonding) as in the OP.

Kitchens do not require SB.

Bathrooms etc. do unless certain conditions are met.
Showers and Baths themselves are unlikely to require SB but the pipes to them might.

 

[ADCG22]

The taps will now be isolated from the metal pipework by the plastic fittings.

However, if the short distance is bridged by the water it could still require the bonding.
I wouldn't think this is likely.

Do you have a multimeter?
If so, set to ohms (Ω) and measure the resistance between the copper on either side of the plastic fittings.

Thanks for your response! The resistance is hovering around 20,000 ohms

 

[EFLImpudence]

Yes, that's ok, then.

 

[ADCG22]

Thanks - what’s the limit? 22,000ohms?

 

[ajohn]

Yes, that's ok, then.

11mA ???

 

[EFLImpudence]

The tap is not the extraneous-conductive-part.

The pipe is and it is bonded.

 

[EFLImpudence]

ADCG22:

I have confused matters.

In answer to your original question, I should have just said "It doesn't matter".
As long as the pipes entering the bathroom are correctly bonded, it doesn't matter what happens to them after that.
So - plumber correct.

I think I was just curious about the resistance across the joints. Sorry.

Thanks - what’s the limit? 22,000ohms?

To determine if a part is an extraneous-conductive-part to the bathroom, from the incoming pipes to the Main Earthing Terminal - 22,000 or 23,000 or 44,000 or 46,000 Ohms (depending on your view of what's more important).
Yours presumably were and so SB has been fitted.

If correctly done this will inhibit voltage difference between (simultaneously accessible) parts during a fault to a maximum of 50V.

So, you now have 20,000Ω between you and even that maximum 50V.


Plus, should you get a shock from the proverbial vacuum cleaner frayed lead live wire while leaning on the taps, you also have the extra 20,000Ω between you and the previously negligible impedance of the earthed (by bonding) taps.