Earth bonding

16 Jul 2006
Reaction score
United Kingdom
Hi folks. Have replumbed my house and it's just occured to me that I didn't remove any earth bonding when I removed the old plumbing, and totally forgot about installing it with the new.

A quick check in the cupboard under the stairs and sure enough the only 3 cables going to the earth block are all 6mm, 1 goes to the earth, one to the CU and one to the economy 7 CU. Nothing goes to the plumbing.

It's a TNS system.

Looking at the earth block, I wont get bigger than a 6mm cable in there.

I have a plastic watermain coming into the kitchen then it converts to 22mm copper.

Bearing in mind that the main earth cable clamped to the earth is only 6mm, can I use 6mm earth cable for my main bonding?

Does the length of the cable run affect things? The easiest route for me to run the cable would be to have one end clamped to the 22mm pipe (just after it converts from the plastic water main), then running up the wall, under the 1st floor floorboards then down into the understairs cupboard, into the earth block. But if I ran it round the edge of the downstairs rooms and through various walls, I could cut 4meters off of the length (although would have to drill some long holes).

The bathroom has a non electric shower (no shower pump etc) and a sink (no bath). I presume (looking at various web pages) I need to supplimemtary bond the 2 pipes supplying the shower and the 2 supplying the sink together?

99% of the plumbing is soldered, but due to a last minute change of plan, I have got one of those push fit copper fittings in one place. Anyone know if I need to bond eitherside of this together or whether the copper push fits don't need bonding.

Sorry for all the questions.


Sponsored Links
Replace the earth block with a new one, fit 16mm² from it to each CU, and 10mm² to it to incomming gas and water services, inform the DNO that they might like to upgrade the earth sweated onto their cable

onto supp bonding...

You have a light in your bathroom, supp bond to the cpc of that as well ;)

Without knowing exactly where the plastic piece is etc, I can't really make too much of a judgement on things except you could but a clamp either side, and bond between them, and treat it as if it was continous copper
Thanks. My bathroom while replumbed, has not had the new basin or shower fitted yet. It would not take a lot for me to replace the copper with plastic in the bathroom. Would this be safer?

I know it's a pain having just installed copper, but I'm thinking of saftey here, it will only take me a few hours to do this, then I wouldn't need to bond the bathroom at all?

My main concern is that it's a small bathroom (not much bigger than 2 standard baths next to each other in size), which is why I've removed the bath and am installing a shower this week, I don't want one of my kids to direct the shower at the light and kill themselves (although they would have to try very hard to do this with the enclosure I've got, but you know kids). Haven't had a look in the attic yet, but if it's possible, I could move the light nearer the opposite corner to the shower?

Which ever option is safer, copper pipe earth bonded or plastic.

Many thanks

Either is fine, as long as bonding is done correctly, with all plastic you don't need to bond at all (...except between cpcs of circuits if multiple circuits in bathroom) with metal bonding is straight forward, but with a mix of the two it becomes slightly more complicated, which is why I suggested bonding across the plastic joint and treating it as if it was a copper one, if it however was mostly plastic with short copper 'tails' on the ends then bonding would not be required because the lengths of plastic would be significant enough that the metal 'tails' would not be ECPs

Lights in zone 2 need to be IPx4 rated, or IPx5 if they might be subjected to water jets, if its in zone 3, then it just has to be suitable for the conditions its likely to encounter, which might mean ipx5 in your case?

Best you don't move the light (unless it happens to be in a stupid zone), not totally sure whether that would be part P notifiable, but feel free to replace the existing light if need be
Sponsored Links
Many thanks.

I did the 10mm bonding today. Will have to call in a pro for the 16mm as the 10mm was bad enough to control. The earth bonding straps said up to 10mm but was a right pain to do. Did the cable up tight, bent the earth cable to make it run a bit neater and the cable moved in the bonding strap.

Finally got there :D

Thanks for the info on the lights. Mine is a suspicious looking thing with a built in heater (works very well mind you), just spent a few mins googling and have found an item that looks identical,

Cant find it's IPx rating though.



DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local