Supplementary bonding question

[Leader]

hi all,

I know there are many questions on this topic but I'm unable to find my answer. Can I connect my 4mm supplementary bonding cable to the cpc in my shaver socket which then links directly back to the light (and via the cpc back to the CU)?

Sorry if it's a basic question, I am still training

 

[hightower]

Very rare you need supplementary bonding nowadays - is this for a college assignment or a job?

 

[Wilko]

Yes, but as HT says it's often not required. Check out reg 701.415.2 as it shows exemptions.

 

[Leader]

Thanks Hightower. This is for my own bathroom, I am rewiring my house. My college tutor said that it's unlikely that all criteria to avoid supplementary bonding would be met so better to put it in.

 

[Leader]

Thanks Wilko. I am looking at 701.415.2 and under it I have written (curtesy of my tutor) "very hard to meet all conditions so better to put it in anyway, this will also cover future use/alterations" and "can only be omitted if maxresistance of extraneous conductive parts to the MET IS 1.66 ohms

 

[Leader]

Another possibly thick question, section (vi) all extraneous conductive parts are effectively connected to the protective equipotential bonding... Does this mean that the water pipes (e.g) are connected to the main incoming water pipe which is itself connected to the MET?

 

[Wilko]

Hi - I think Tutor means less than 1.67k Ohms, from 50V / 30mA (assuming RCD). That's easily checked
The 3 conditions in 701.415.2 are easily complied with, I think. ADS tick, RCD tick, water and gas bonded to MET tick.
Maybe I am missing something?
Edit : yep, check bathroom for any extraneous conductive parts and bond if required. @Pete999 has a top video.

 

[Leader]

Thank you. I think you have answered my "thick" question too.

 

[hightower]

I think it's extremely unlikely that all criteria will NOT be met in fairness

 

[westward10]

Answer to your original question, yes.

 

[Leader]

Thanks all. I'm glad at least my wiring is ok even if I didn't need to do it. On the plus side at least I don't have to do it for the other bathroom.

 

[Pete999]

hi all,

I know there are many questions on this topic but I'm unable to find my answer. Can I connect my 4mm supplementary bonding cable to the cpc in my shaver socket which then links directly back to the light (and via the cpc back to the CU)?

Sorry if it's a basic question, I am still training

 

[Risteard]

As others have said it's certainly not unlikely that all conditions for omitting supplementary bonding will be met where all bathroom circuits are RCD protected. That said, I personally prefer supplementary bonding as it does not require (an) electromechanical device(s) to be operating correctly. So you could install it in addition to (but certainly not instead of) RCD protecting all circuits of the location.

 

[Risteard]

Sorry just noticed this thread is a few weeks old. Not sure why it appeared in the new topics section? Perhaps someone posted and then deleted their post.

 

[Leader]

Thanks anyway Risteard! I did put it in ready to be connected to the shaver socket but then it got taken out as the tiler forgot to run it up the wall to the shaver point! As others had said it wasn't really necessary I didn't put up a fight.

 

[kingeri]

It's something you encounter on rewires, unless there's a compelling reason to remove it, I leave it in. I added it to my own bathroom even though it isn't strictly necessary, but it gives me a bit more piece of mind. RCDs do fail, and they can stick, especially when the test button hasn't been pressed in years. I sincerely believe that the most important thing you're doing when pressing the test button (other than testing the function of the RCD) is actually loosening up the switch!

 

[Midwest]

The other thing to consider, is the pipe in question actually extraneous. With the advent of plastic pipes, pushfit fittings one can actually make something extraneous by bonding it, when it's not in the first place.

So test it first, as per Petes #12. Just my opinion.

 

[Risteard]

With the advent of plastic pipes, pushfit fittings one can actually make something extraneous by bonding it, when it's not in the first place.

To be pedantic they can't make it extraneous. It either is or isn't. But they can introduce an earth reference that previously didn't exist because they were non-extraneous.

 

[Midwest]

To be pedantic they can't make it extraneous. It either is or isn't. But they can introduce an earth reference that previously didn't exist because they were non-extraneous.

Couldn't put it better myself, oh no you did!