Shower and Bathroom floor Bonding

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Post by Slovett »


Just a question about - Bonding in Showers and Bathroom floors and walls.

This has to be the least followed Rule in 3000 - Every time I'm Bonding the steel in a concrete floor the Council Inspectors always ask me what Im doing and look at me like a crazy man when I explain.

Anyway - My question is how can you test the effectiveness of the connection and resistance etc. once the concrete is poured? (I always make sure I have an effective connection between earth cable and the steel in the wet areas before the pour) Also how can we tell if the floor has an effective bond to earthing system when there is no access to the concrete once finished? (ie water proofed, tiled, vinyl, varnish etc) - I guess maybe testing the concrete footing outside close to the Bathroom??

Also - Who else here bothers with the floor bonding?? - I guess the only way to effectively enforce the rule, would be to make it part of the Councils pre pour inspection? (The same should also be for Pools Because I would guess that 90% of all new homes build in the last 15 years don't have their wet area floors bonded
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Re: Shower and Bathroom floor Bonding

Post by AlecK »

The effectiveness of the bonding connection to conductive reinforcing should be tested before the concrete is poured.
The risk of the pour breaking the connection should be very low.
If the EBC isn't fully run at at time of pour, you can test the continuity of the rest when you complete the run.
Add the result to the pre-pour test result to get a total back to earth bar

If the slab / foundation is used as the earth electrode (making this conductor the MEC rather than an EBC); it's mandatory to make the connection accessible for testing. Which is not difficult to arrange, and can also be done for EBCs.

There is a test method in IEC Standards that, maybe with some amendment, would perhaps be usable after the pour for checking EBCs.
It's specified to testing 'earthed environment' situations; which our wiring Rules don't recognise as a method of protection.
And it requires making up special equipment, so unlikely to become commonplace for EBCs.
How it would be affected by floor finishes / coverings I'm not sure.

The ignorance of Building Inspectors with regard to electrical matters is endless;
and we should be very glad that most "energy work" (gas & electrical) is not under their jurisdiction.

I agree that both wet-area bonding and pool bonding would likely improve if they were educated about it; and made it part of their pre-pour checklist. But only as a heads-up reminder, not in a way that gave them any more authority than they have now.

Perhaps better to educate the builders (& pool-builders) directly.
I suspect that one reason pours happen without binding being done is the sparkies are too lazy to even talk to the builder and tell them bonding is needed pre-pour. If you do that - in writing (condition of tender?) - and the builder doesn't co-ordinate it; then cost of accessing the reinforcing later, and patching the concrete should be an extra.
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