Earth wire for bath: BS6231 or BS6491 ?
- Thread starter Possom
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The answer to your question is "no"
because baths are not normally bonded.
Supplementary bonding in a bathroom, when required, is done to the metal services entering the bathroom at the point where they enter, or just outside (for example in an adjacent airing cupboard). In some cases supplementary bonding is not required.
The services would normally be the copper hot and cold tapwater pipes; the radiator flow and return; somettimes lead or cast-iron drains or soil-pipes, though plastic is now more common.
Having bonded the services where they enter, you don't need to bond the iron bath that the pipes attach to, because the pipes have already been done and there is no other source in the bathroom that can provide voltage to the bath.
The bonding is connected to all the electrical circuits that enter the bathroom. usually lights, may also be an immersion heater, shower pump, convector heater, electric towel rail, supply to shaver point, electric shower.
There is probably a ready-written guide, I will see if I can find it. Or someone may beat me to it.
edit
wording improvement
because baths are not normally bonded.
Supplementary bonding in a bathroom, when required, is done to the metal services entering the bathroom at the point where they enter, or just outside (for example in an adjacent airing cupboard). In some cases supplementary bonding is not required.
The services would normally be the copper hot and cold tapwater pipes; the radiator flow and return; somettimes lead or cast-iron drains or soil-pipes, though plastic is now more common.
Having bonded the services where they enter, you don't need to bond the iron bath that the pipes attach to, because the pipes have already been done and there is no other source in the bathroom that can provide voltage to the bath.
The bonding is connected to all the electrical circuits that enter the bathroom. usually lights, may also be an immersion heater, shower pump, convector heater, electric towel rail, supply to shaver point, electric shower.
There is probably a ready-written guide, I will see if I can find it. Or someone may beat me to it.
edit
wording improvement
Last edited:
There is no such thing as "earth bonding".
Either one could be used, although BS6491 is the more usual choice. BS6231 is generally used for panel wiring.
BS7671 does not require either of those, the only requirement is the cross sectional area of the copper conductor.
However baths do not need to be bonded and never did, so in that instance the answer is none of them.
BS7671 does not require either of those, the only requirement is the cross sectional area of the copper conductor.
However baths do not need to be bonded and never did, so in that instance the answer is none of them.
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Does a steel bath with copper water pipes not require supplementary bonding? I had read elsewhere that the regs state that: All exposed conductive or extraneous metalwork must be connected to earth.
As said, the pipes might require supplementary bonding.
Supplementary bonding might be required because they are earthed. If they have no connection to earth then they must not be bonded.
They might not be earthed. You cannot tell by looking at them. It requires measurements.
That is true but it is not what you are asking and not done with supplementary bonding.
Exposed-conductive-parts and extraneous-conductive-parts to the building should/will be connected to the Main Earthing Terminal by main bonding.
Extraneous-conductive-parts to the bathroom might require supplementary (which just means additional) bonding between parts because they are earthed to reduce the potential difference between them in the event of a fault.
Only in very exceptional circumstances - such as when the bath has a metal waste pipe which disappears underground somewhere.
I think you must have mis-read that, since almost everything about that statement is wrong. "All exposed conductive ... metalwork" would include things like door knobs, coat hooks, cutlery etc. etc. Furthermore bonding (whether supplementary or otherwise) is NOT about "connecting to earth" - rather, it is about "connecting things together" (to ensure that they cannot be at different voltages).
Kind Regards, John
Are you sure about that? See what I've just written about "All exposed conductive (or extraneous) metalwork must be connected to earth." (my parenthesis and emboldening).
Kind Regards, John
That's not exactly what it says, although it's along the general idea.
However it's important to understand what those definitions actually mean.
An exposed conductive part is 'a conductive part of equipment which can be touched and which is not normally live, but can become live under fault conditions'. Equipment in this context referring to electrical equipment.
A bath is clearly not electrical equipment or part of any electrical installation, so the 'exposed conductive part' does not apply to a bath.
An extraneous conductive part is 'a conductive part liable to introduce a potential, generally Earth potential, and not forming part of the electrical installation.
A metal bath meets those criteria for being conductive and not part of the electrical installation, but it cannot introduce any potential, as it's just a free standing object.
No different to a metal bucket placed in a room, or a metal door handle, or a metal spoon in a drawer of cutlery.
Metal pipes are extraneous conductive parts, as they will typically enter the room from some other location and often be in contact with earth or other conductive items, which themselves may be in contact with the earth, or are connected to other items such as the casing of a boiler, immersion heater and so on.
However a piece of copper pipe just screwed to the wall is not, and therefore would not require bonding. Neither does a section of copper pipe between two plastic sections.
However it's important to understand what those definitions actually mean.
An exposed conductive part is 'a conductive part of equipment which can be touched and which is not normally live, but can become live under fault conditions'. Equipment in this context referring to electrical equipment.
A bath is clearly not electrical equipment or part of any electrical installation, so the 'exposed conductive part' does not apply to a bath.
An extraneous conductive part is 'a conductive part liable to introduce a potential, generally Earth potential, and not forming part of the electrical installation.
A metal bath meets those criteria for being conductive and not part of the electrical installation, but it cannot introduce any potential, as it's just a free standing object.
No different to a metal bucket placed in a room, or a metal door handle, or a metal spoon in a drawer of cutlery.
Metal pipes are extraneous conductive parts, as they will typically enter the room from some other location and often be in contact with earth or other conductive items, which themselves may be in contact with the earth, or are connected to other items such as the casing of a boiler, immersion heater and so on.
However a piece of copper pipe just screwed to the wall is not, and therefore would not require bonding. Neither does a section of copper pipe between two plastic sections.
Yes, in as much as I said "exposed- and extraneous-conductive-parts" as in our definitions.
Obviously if what Possom read did actually say "all exposed (conductive) metalwork" then it is not true.
Also - Possom did say he read "All exposed conductive or extraneous metalwork must be connected to earth" so some distinction must be made between "all metalwork".
Exposed conductive parts are Earthed - not bonded.
It was the 8th post here where I read it:
https://www.diynot.com/diy/threads/earthing-a-steel-bath.7339/
"All exposed conductive or extraneous metalwork must be connected to earth"
That is poor wording but essentially true.
The point is your bath is neither using the definitions.
Fair enough, but the same result for the OP.
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