Replacement Bathroom and an old Earth cable

[DaveyD]

Hi Chaps,

I'm going to replace an old bathroom suite, it only has an earth cable connected to the bath.

Can I just replace the Suite and connect the old earth cable to the bath, or do I have to upgrade the earth bonding?

Thanks,
Dave

 

[EFLImpudence]

It is not possible to tell from here what bonding is required.

Is there RCD protection on ALL the circuits which enter the bathroom?

 

[DaveyD]

There's just 1 earth connecting to the bath. The sink and toilet copper pipework have no earths.

I'm wondering if I can just leave it like that when I replace the Suite, or will I have to upgrade the earth bonding to BS7671.
There is no RCD protection in the house.

 

[EFLImpudence]

It is not possible to tell from here what bonding is required.

It will require testing to determine this.

What electrical appliances are in the room and do they have any touchable metal parts?
Lights, heater?

Is there a shower with touchable water pipe showing?

 

[DaveyD]

There are no other electrical appliances in the room, only the light and thats a plastic rose.

There isn't a shower either.

 

[EFLImpudence]

In that case, I would not connect the cable to the bath.
Because the plastic light fitting is the only electrical part in the room, the main reason for bonding is not present in your bathroom.


Out of interest, do you know where the cable is connected at the other end of it?

 

[DaveyD]

Thank you for that, I hadn't even thought of it like that.

I'm not sure where the earth wire goes, but it eventually must connect to the consumer unit as I get a circuit with the test meter on ohms and a test wire to make a loop.

 

[JohnW2]

In that case, I would not connect the cable to the bath.
Because the plastic light fitting is the only electrical part in the room, the main reason for bonding is not present in your bathroom.

In electrical terms, that makes total sense. However, 701.451.2 is potentially confusing. It appears to require that (if conditions for omission of supplementary bonding are not satisfied) SB must be installed between extraneous-c-ps and the CPCs of each circuit supplying the room, even if there are no exposed-conductive-parts and, indeed, even if all the equipment supplied in the room is Class II.

Kind Regards, John

 

[EFLImpudence]

I am not by my book to see the exact wording but if you think it is confusing, yet what I said makes sense, I will stick with what I have written.

Does the main requirement for supplementary bonding not state exposed-cps and extraneous-c-ps be connected so with no exposed-c-ps...?

What would you do if there were no light?

 

[JohnW2]

I am not by my book to see the exact wording but if you think it is confusing, yet what I said makes sense, I will stick with what I have written.

Very sensible [note that I said that it makes electrical sense!].

Does the main requirement for supplementary bonding not state exposed-cps and extraneous-c-ps be connected so with no exposed-c-ps...?

Nope - and that was my point - it does not mention exposed-c-ps at all. It says:

"Local supplementary bonding according to regulation 415.2 shall be established connecting together the terminals of the protective conductor of each circuit supplying Class I or Class II equipment to the accessible extraneous-c-ps, within a room containing a bath or shower ...."

Admittedly, 415.2 (4.5.2.1) says that supplementary bonding should "include" all "simultaneously accessible exposed-c-ps", but it says nothing to suggest that it over-rides the general requirement of 701.415.2, even if there are no exposed-c-ps to "include".

What would you do if there were no light?

If there were no light (and no other electrical equipment), hence no Class I or Class II equipment in the room, then I presume that 701.415.2 does not, and cannot, apply?

Kind Regards, John

 

[EFLImpudence]

You are, of course correct in what you said.

Does the main requirement for supplementary bonding not state exposed-cps and extraneous-c-ps be connected so with no exposed-c-ps...?

Nope - and that was my point - it does not mention exposed-c-ps at all. It says:

"Local supplementary bonding according to regulation 415.2 shall be established connecting together the terminals of the protective conductor of each circuit supplying Class I or Class II equipment to the accessible extraneous-c-ps, within a room containing a bath or shower ...."

I did actually mean 415.2.1 (as you go on to say)

Admittedly, 415.2 (4.5.2.1) says that supplementary bonding should "include" all "simultaneously accessible exposed-c-ps", but it says nothing to suggest that it over-rides the general requirement of 701.415.2, even if there are no exposed-c-ps to "include".

701.415.2 says according to 415 which does have a note - additional requirements may be necessary for special locations.

It's difficult to imagine why the cpcs should be mentioned rather than the exposed-c-ps - but of course it then include the class II items - not sure why.
What about 12V lighting? Still connect the cpc?

What would you do if there were no light?

If there were no light (and no other electrical equipment), hence no Class I or Class II equipment in the room, then I presume that 701.415.2 does not, and cannot, apply?

What I meant was, would you consider it necessary to connect together just the extraneous-c-ps?



Anyway, without extensive information about the OPs installation, with no exposed-c-ps I would still prefer the actual bath not to be connected.
Should the pipes be correctly bonded elsewhere, or not require it at all, then the bath need not be connected.
Should there be no bonding though required OR
Should there even be no MAIN bonding the situation is still better with the bath not connected.

 

[JohnW2]

701.415.2 says according to 415 which does have a note - additional requirements may be necessary for special locations.

It does - but, as I said, it only talks about the things that require SB "including" exposed-c-ps, so I don't think that lets one of the hook of having to bond other things (like the CPCs of Class II equipment!) called for by those "additional requirements" in 701.415.2, does it?

It's difficult to imagine why the cpcs should be mentioned rather than the exposed-c-ps - but of course it then include the class II items - not sure why.

Quite so. It makes very little sense. Class II items don't even have CPCs connected to them (at most, have a 'parking space' for a CPC), so the CPC can only really relate to the cable/circuit, not to the 'equipment'

What about 12V lighting? Still connect the cpc?

It's seemingly silent about that - is the implication that the same requirements apply as for 230V equipment? Who knows!

QUOTE="EFLImpudence, post: 3577965, member: 144975"]What would you do if there were no light?

If there were no light (and no other electrical equipment), hence no Class I or Class II equipment in the room, then I presume that 701.415.2 does not, and cannot, apply?

What I meant was, would you consider it necessary to connect together just the extraneous-c-ps?

As I said, if there are no Class I or Class II items in the room, there cannot be any "circuits supplying Class I or Class II equipment in the room", hence no relevant circuits whose CPCs one could be required to connect together?

Anyway, without extensive information about the OPs installation, with no exposed-c-ps I would still prefer the actual bath not to be connected.

I agree - as you say, probably regardless of anything else.

Kind Regards, John

 

[EFLImpudence]

Do we regard ceiling roses as Class II?

 

[JohnW2]

Do we regard ceiling roses as Class II?

Well, they're made of a pretty tough material, which I would have thought probably would have qualified as "double or reinforced insulation", but I'm sure you won't find a DI symbol on them! As for what might dangle out of a ceiling rose, that's a rather different question!

Kind Regards, John