Bathroom regs Questions

[maudy]

HI everyone,
Could I just check that i'm right on the following.......

1. Supplementary bonding of any kind is not needed in a bathroom where the circuits are protected by an RCD?
2. A bathroom extraction fan can be run directly off an (RCD protected) lighting circuit without the need to install an isolator (and in fact the need to install isolators for everything in a bathroom is purely illusionary (maybe a myth propogated by isolator sales sharks)?
3. I can install an IP44 rated illuminated mirror above a bathroom sink if its on a rcd protected circuit?

Sorry to ask such elementary level questions but I'm suffering from regs blindness.

 

[acvc]

Three conditions for omitting supplementary bonding:
1. Measured continuity between extraneous conductive parts in the bathroom and the MET, and below 1667ohms.
2. All circuits passing through the location must be protected by 30mA RCD.
3. RCD disconnection times must comply.

 

[Dan the spark]

I'd put the fan thru an isolator as then you can turn it off to work on or if there is a fault wit it

 

[Richard Burns]

All circuits in a bathroom require 30mA RCD protection.
A fan isolator is not required (unless specified in the manufacturer instructions) but can be useful.
Mirror above a sink (assuming not near a bath/shower is outside of zones so needs to be suitable for the location an IP44 illuminated mirror should be fine.
Supplementary bonding omission is reg 701.415.2: 30mA RCD protection for all final circuits, main bonding of all extraneous conductive parts, meets ADS requirements.

 

[dichroic]

View attachment Extractor fans in dwellings.pdf

I hope this helps with your question on the extractor fan / isolation query.

Dichroic

 

[Vito04]

Three conditions for omitting supplementary bonding:
1. Measured continuity between extraneous conductive parts in the bathroom and the MET, and below 1667ohms.
2. All circuits passing through the location must be protected by 30mA RCD.
3. RCD disconnection times must comply.

Are you sure about that:

' 1. Measured continuity between extraneous conductive parts in the bathroom and the MET, and below 1667ohms'.

 

[MarkieSparkie]

Are you sure about that:

' 1. Measured continuity between extraneous conductive parts in the bathroom and the MET, and below 1667ohms'.

It should not be determined by a continuity test or at that value:
To determine if a part is extraneous, or just a piece of metal, test with an Insulation Resistance Tester on the MOhm range at 500Vdc between the suspect metal part and the MET, if the reading is 0.022M Ohms (22K Ohms *) or greater supplementary bonding is not required.
* Conservative traditional value used by most electricians, however GN8 advises 23K Ohms and ESC/NICEIC advise the ultra-conservative 7K Ohms.

 

[Deleted member 9648]

It should not be determined by a continuity test or at that value:
To determine if a part is extraneous, or just a piece of metal, test with an Insulation Resistance Tester on the MOhm range at 500Vdc between the suspect metal part and the MET, if the reading is 0.022M Ohms (22K Ohms *) or greater supplementary bonding is not required.
* Conservative traditional value used by most electricians, however GN8 advises 23K Ohms and ESC/NICEIC advise the ultra-conservative 7K Ohms.

Incorrect when applied to supplementary bonding.....acvc is correct.The measurment should be carried out between exposed conductive parts and suspected extraneous conductive parts and where protection by 30ma rcd is applicable should be <1667 ohms. See note at end of 701.415.2 and 415.2.2

 

[Doomed]

I thought that a fan isolator only HAD to be fitted if there was no source of natural light. (I would always fit one though).
Also don't forget the fuse which is commonly asked for by fan manufacturers. (My boss hates me fitting a fuse by the fan isloator for some reason).

 

[Plonker 3]

I normally just fit a switch fuse spur with a 3 amp fuse for the lighting circuit,as that is what most manufacturers require that be fitted where a fan is installed anyway.

 

[Plonker 3]

I thought that a fan isolator only HAD to be fitted if there was no source of natural light. (I would always fit one though).

But why would this only apply to bathrooms, do we have to fit a emergency light in other rooms without a natural source of light?

 

[maudy]

Incorrect when applied to supplementary bonding.....acvc is correct.The measurment should be carried out between exposed conductive parts and suspected extraneous conductive parts and where protection by 30ma rcd is applicable should be <1667 ohms. See note at end of 701.415.2 and 415.2.2

Thanks guys for all your responses, they have all been helpful but i'm still a little in the dark with regards to the supplementary bonding issue.

There seems to be some debate within the responses but I think maybe if I provide more info it might help:

The bathroom is supplied by plastic water pipe.
I've just put in main equipotential bonding (there was none previously).
The bathroom furniture is the type which doesn't allow any access to the pipes themselves (new swanky cabinet style bog, sink etc).

Do I still have to supplementary bond it?

 

[Deleted member 9648]

Thanks guys for all your responses, they have all been helpful but i'm still a little in the dark with regards to the supplementary bonding issue.

There seems to be some debate within the responses but I think maybe if I provide more info it might help:

The bathroom is supplied by plastic water pipe.
I've just put in main equipotential bonding (there was none previously).
The bathroom furniture is the type which doesn't allow any access to the pipes themselves (new swanky cabinet style bog, sink etc).

Do I still have to supplementary bond it?

It is the pipes which intoduce a potential to the location...if they are plastic they will not intoduce a potential and so no supplementary bonding is required or possible. If they were metallic you would measure continuity between conductive parts within the location,and extraneous conductive parts which may introduce a potential,if you got a reading of less than 1667 ohms then there is adequate continuity between them and the main earthing/bonding system. If your reading exceeded 1667 ohms then there isnt and you would need to supplementary bond regardless of RCD protection. Reg 701.415.2 is a rare instance of a reg which is quite clear in it's requirements,why the confusion?

 

[dichroic]

The question sometimes arises of whether supplementary bonding is required to metallic parts such as radiators, taps and short sections metallic pipework, supplied by plastic water pipework in locations containing a bath, shower or swimming pool. Supplementary bonding is not required to a metallic part if the length of water-filled plastic pipe supplying the part is sufficient to limit the shock current through the part to 30 mA or less under earth fault conditions. In fact it is best not to bond the metallic part in these circumstances, as this would cause the part to be at earth potential, thereby increasing the risk of electric shock to a person inadvertently in direct contact with a live part whilst simultaneously touching the metallic part.

Although supplementary bonding may be omitted from a bath or shower location in any case if all three conditions in Regulation 701.415.2 for its omission are met, the bonding should not be omitted if any of the conditions is not met. This could be the case, for example, where an alteration or addition is carried out in a bathroom originally wired to the 16th Edition or earlier of the IEE Wiring Regulations, where an existing unaltered circuit of the location is not protected by an RCD with a rated residual operating current (IΔn ) of 30 mA or less. So the question of whether or not to bond metallic parts supplied by plastic water pipework is still valid.

To limit the shock current through a supplied metallic part to 30 mA or less in the event of an earth fault, the resistance of a water-filled plastic water pipe and its contents between that part and any metalwork connected to either Earth or the main earthing terminal (MET) of the installation must exceed 230 V ÷ 30 mA; that is, 7.67 kΩ (assuming a nominal voltage U of 230 V a.c.).

Dichroic