Bonding a towel rail

[Chri5]

Last few jobs I've done bathroom lights and shaver points as a dedicated final circuit.

What do you mean here? A circuit with its own MCB at the CU?

How will this future-proof the installation?

The bathroom circuit is via seperate 10a MCB and RCD protection, the 1st floor lighting circuit isn't- by splitting them the bathroom will comply with 17th ed future requirements and the 1st floor lighting won't suffer nuisance trips, cause it's not on RCD
I'm not keen on RCD for all the lighting on a 1st floor due to trips caused by simple bulb failure.

 

[Doctor Drivel]

Last few jobs I've done bathroom lights and shaver points as a dedicated final circuit.

What do you mean here? A circuit with its own MCB at the CU?

How will this future-proof the installation?

The bathroom circuit is via seperate 10a MCB and RCD protection, the 1st floor lighting circuit isn't- by splitting them the bathroom will comply with 17th ed future requirements and the 1st floor lighting won't suffer nuisance trips, cause it's not on RCD
I'm not keen on RCD for all the lighting on a 1st floor due to trips caused by simple bulb failure.

Chris, thanks. It appears you "think" you know what way the 17th is going.

So, if a bathroom has a shaver socket and just lights, having its own 10A RCBO at the CU, or on the RCD protected circuit, would "in the 17th" eliminate the need for bonding of the bath, basin and towel rail or rad?

Can this bathroom RCD/RCBO be in the bathroom cupboard and taken off the adjacent lighting or socket circuits for convenience? I would assume so.

Of course I know none of this is finalised yet at all.

As to immersion heaters, etc in bathrooms, they are, 9/10, in a separate cupboard which is not regarded as the bathroom.

 

[Doctor Drivel]

The towel rail doesn't have to be bonded. If the pipes come from outside the bathroom in copper they do. If they are just copper drops they don't.

If they do come from outside the bathroom in copper and you can confirm continuity you can bond them in an adjacent airing cupboard. They have to be bonded to each other and to any other copper services that are in the bath/shower room and the protective conductor of any electrical appliances in zones 1, 2 or 3(within 3 meters of bath or shower door). use 4mm csa. If there are no electrical appliances take the bonding to the light fitting cpc.

middle of next year bathroom lights and electrical applainces will be suplementary protected by rcd instead of suplementary equipotential bonding. Some electricians in this town are working to those regs already. . I would continue with bonding and provide the soon to be required rcd protection also until the new regs apply whence I would take off the bonding..

Firstly, if the bath, basin and shower are in plastic pipe and the rad is in copper, does the rad need bonding?

Secondly, looking ahead I know, will all appliances (high level heaters on pull chords too) and electrical equipment in cupboards in bathroooms, such as: boilers, pumps, etc, need to be on RCD protection too.

 

[RF Lighting]

HOW MANY TIMES????



WE DO NOT KNOW



UNTIL THE 17TH EDITION IS PUBLISHED NO ONE KNOWS WHAT WILL ACTUALLY BE WRITTEN IN IT.

So there really is no point trying to guess what changes will be introduced, and how to comply with them.

 

[Taylortwocities]

Why does he call himself Dr Drivel?

 

[Paul Barker]

Firstly, if the bath, basin and shower are in plastic pipe and the rad is in copper, does the rad need bonding?

For present standards, the suplementary equipotential bonding in a bathroom applies to metalwork that could introduce a potential from outside the bathroom. So copperpipewrok to a radiator all the way you bond the pipework, but not the radiator. Just a short drop of copper to plastic pipe and you bond neither. The bonding has to go to the cpc of any electrical applainces in the zones.

The protection for your scenario works as follows. If you had not caged the copper pipes which introduce a ground potential from outside the zone to the shower and you touchjed both the shower and the radiator the full voltage potential nominally 230v is bridged by your wet body. This would result in current flow, that might harm or kill you. If the two are equipotentially bonded, there is no potential difference so no current flow.

As the other guys said we don't know for sure what comes next.

To my mind the whole equipotential bonding issue is in need of more acurately prescriptive detal in the regs I hope that better leadership results in a few important issues being clarified in the forthcoming regs with ratianalle.

 

[Doctor Drivel]

Why does he call himself Dr Drivel?

In see it regularly.

 

[Jolly Roger]

Given that the rail needs bonding, does the bond have to be accessible / available for inspection i.e. not under the floor? Can't see a way round having the tag visible if it does.
Also, how far back does the bonding go - to the flex outlet, the RCD...?

 

[JohnD]

Given that the rail needs bonding, does the bond have to be accessible / available for inspection i.e. not under the floor?

yes
But why do you say it is "given" since it is the metal pipes that need to be bonded, not the rail?

Can't see a way round having the tag visible if it does.

tough

Also, how far back does the bonding go - to the flex outlet, the RCD...?

It goes to the earthwire (CPC) of each circuit entering the bathroom. This is usually the light switch, may also be a wall heater, imersion heater, shower pump, wall heater, shaver socket if these are present in the bathroom and supplied from different circuits.

 

[plugwash]

To my mind the whole equipotential bonding issue is in need of more acurately prescriptive detal in the regs I hope that better leadership results in a few important issues being clarified in the forthcoming regs with ratianalle.

I thought they were planning to scrap it at least in bathrooms (which are the only common domestic situation where it is required)

 

[Jolly Roger]

Thanks for the reply, JohnD.

You are quite right - it is the copper tubing I shall be bonding not, not the towel rail, which is plated anyway. My "given" comment was simply acknowledging that bonding is required.

I was toying with the idea of taking the flex through the wall ,but think I shall settle for a flex outlet in the bathroom and will take the bonding earth back to that.