bathromm earth bonding

[mikegray]

my bathroom is piped in mainly in plastic

the plastic is connected to copper pipes which then feed the basin taps

then same with the toilet, a peice of copper runs from the plastic pipe
to the cistern

Do i need to cross bond theese copper pipes ??

 

[andy]

no

 

[mikegray]

Thanks

The bath also sits on two metal supports
do theese need eathing

its a spa bath, so its has a 240v supply

Mike

 

[Agile]

Earthing the supports depends on what the bath is made of. If its a plastic bath then I would bond the taps and waste together. Opinion is devided as to whether you should bond further when the supply and waste pipes are all plastic.

All earth bonding in a bathroom should be done by a test qualified electrician ( and normally to the light switch earth ).

Next question comes as to what to do with the radiator if its fed by copper pipe!

If the radiator is fed with plastic pipe many treat it as if its floating but in reality its well earthed by the system water either because its dirty or treated with inhibitor. When I say well earthed, I mean in comparisom with the impedance of a damp human body ( about 5-50 K ) the radiator being say 200-2000 ohms to earth depending on the water.

Tony Glazier

 

[ban-all-sheds]

Earthing the supports depends on what the bath is made of. If its a plastic bath then I would bond the taps and waste together.

Why?

Opinion is devided as to whether you should bond further when the supply and waste pipes are all plastic.

On almost any topic, some people hold views which are correct, and some people hold views which are incorrect.

All earth bonding in a bathroom should be done by a test qualified electrician

Who says so?

Where do they say it?

If the radiator is fed with plastic pipe many treat it as if its floating but in reality its well earthed by the system water either because its dirty or treated with inhibitor. When I say well earthed, I mean in comparisom with the impedance of a damp human body ( about 5-50 K ) the radiator being say 200-2000 ohms to earth depending on the water.

No - over 20kohms per metre of plastic pipe for water with a double dose of inhibitor:

http://www.iee.org/Publish/WireRegs/EarthingPlasticPipes.pdf

 

[Agile]

""Earthing the supports depends on what the bath is made of. If its a plastic bath then I would bond the taps and waste together"".

Why? Answer: because the IEE recomendations in your quote say so!

Quote:
Opinion is devided as to whether you should bond further when the supply and waste pipes are all plastic.

On almost any topic, some people hold views which are correct, and some people hold views which are incorrect. Answer: Agreed.

Quote:
All earth bonding in a bathroom should be done by a test qualified electrician

Who says so?

Where do they say it?

Answer: It is generally agreed ( except perhaps by you ) that ALL wiring in special zones ( including bonding ) needs to be done by a fully qualified electrician. But my source is the teamleader of Ealing Building Control Officers who acts in his Authority as co-ordinator of consistency with other London Boroughs on Part P. If thats what the building control officer expects then thats what he gets!

Quote:
If the radiator is fed with plastic pipe many treat it as if its floating but in reality its well earthed by the system water either because its dirty or treated with inhibitor. When I say well earthed, I mean in comparisom with the impedance of a damp human body ( about 5-50 K ) the radiator being say 200-2000 ohms to earth depending on the water.

No - over 20kohms per metre of plastic pipe for water with a double dose of inhibitor:

Answer: Not "No". Thats with a double dose of inhibitor, I agree. But any heating system MIGHT have a greatly increased conductivity due to the use of too much soldering flux ( HCl ) or washing up liquid ( NaCO3 ) as a flushing agent. You cannot know whats in it.

Also each radiator has a flow and a return pipe which reduces the impedance by at least half.

In any case the IEE has added to the quote you referred to : "" Edited Nov 2002 The IEE accepts no liability for the opinions expressed above. ""

I interpret that as implying that they cannot fully endorse, to the point of accepting legal liability, those opinions. As I said above, the CH water can be well or badly earthed depending on chemical content, which is unknown.

Example of unsafe: Unearthed metal radiator fed by plastic pipe. Installer screws radiator bracket into wall with steel screws. Screw penetrates buried mains cable and contacts live conductor! Earthed radiator would blow fuse or trip MCB. Unearthed radiator will be live and a severe shock hazard in zone 2/3.

Tony Glazier

 

[ban-all-sheds]

""Earthing the supports depends on what the bath is made of. If its a plastic bath then I would bond the taps and waste together"".

Why? Answer: because the IEE recomendations in your quote say so!

my bathroom is piped in mainly in plastic

the plastic is connected to copper pipes which then feed the basin taps

From the IEE recommendations:

It seems to be the practice of some builders to
effect all the plumbing in plastic except for those
bits of the pipework that are visible. These short
lengths of metal pipework supplied by plastic
pipes or metal taps connected to plastic pipes,
metal baths supplied by plastic pipes and with a
plastic waste do not require supplementary
bonding.

Figure 2 shows the supplementary
bonding required in a bathroom where the
pipework is plastic.

I see no bonding connections to the taps or the waste in Figure 2.

From the table listing what to do with various combinations of plastic & metal pipes, the instance when all pipes are plastic:

Bonding of metal taps,
metal radiators or metal
baths is not required unless
the bath is connected to the
metallic building structure.

When the water and wastepipes are plastic, but the CH is not.:

Bonding of metal water
taps is not required, nor
metal baths unless
connected to the metallic
building structure.

Would you care to explain "because the IEE recommendations in your quote say so" in a little more detail?

Quote:
All earth bonding in a bathroom should be done by a test qualified electrician

Who says so?

Where do they say it?

Answer: It is generally agreed ( except perhaps by you ) that ALL wiring in special zones ( including bonding ) needs to be done by a fully qualified electrician. But my source is the teamleader of Ealing Building Control Officers who acts in his Authority as co-ordinator of consistency with other London Boroughs on Part P. If thats what the building control officer expects then thats what he gets!

No - it is not generally agreed that this is the case.

There is no law that says it.

Building Control Officers do not have the power to enact legislation, or lay Statutory Instruments before Parliament. Building Control Officers do not have the power to amend existing legislation, or existing Statutory Instruments. Ealing Building Control Officers can "expect" what they damn well like, but there is no legal basis whatsoever on which they can insist on it, and anybody who is not stupid enough to believe the nonsense that you are spouting can push back and demand that they not prevent what the law allows, and demand that they carry out what the law says are their responsibilities.

Answer: Not "No". Thats with a double dose of inhibitor, I agree. But any heating system MIGHT have a greatly increased conductivity due to the use of too much soldering flux ( HCl ) or washing up liquid ( NaCO3 ) as a flushing agent. You cannot know whats in it.

Well then maybe as a fully qualified electrician you should test the impedance of the radiators back to earth before potentially making them less safe by bonding them without any thought? If people like you are so special that only you should be allowed to work on wiring in bathrooms, maybe you should use your enhanced knowledge and understanding of electricity?

From those recommendations again:

An earthy environment where there are lots of
metal pipes is potentially less safe than an earth
free environment.

Metal radiators supplied by plastic pipes should
not be supplementary bonded. It is not safer to
supplementary bond them, it is safer not to.
Locations generally are safer if the location is
earth free as discussed earlier.

In any case the IEE has added to the quote you referred to : "" Edited Nov 2002 The IEE accepts no liability for the opinions expressed above. ""

Yes - Paul Cook is a dangerous and incredibly ignorant man, isn't he.

I interpret that as implying that they cannot fully endorse, to the point of accepting legal liability, those opinions. As I said above, the CH water can be well or badly earthed depending on chemical content, which is unknown.

How much current is needed to be dangerous? Use the lowest estimate, work out what that implies in terms of the lowest resistance to earth that a radiator can be before it becomes unsafe, see what you have to assume as the resistance of the water in the pipes compared to the values found by the researchers, and think about whether you are likely to be making things more, or less, safe by bonding the radiators.

Example of unsafe: Unearthed metal radiator fed by plastic pipe. Installer screws radiator bracket into wall with steel screws. Screw penetrates buried mains cable and contacts live conductor! Earthed radiator would blow fuse or trip MCB. Unearthed radiator will be live and a severe shock hazard in zone 2/3.

No - that's an example of a situation which if you really believed it, would see you also bonding everything metal screwed to the walls, like toothbrush holders, towel rings, grab rails, robe hooks, shower curtain tracks - do you really do this?

 

[Agile]

I do not do electrical work in bathrooms because I do not have the right certificates yet. I work within the ( commonly thought ) limits of legality and particularly I do not argue with Building Inspectors, I treat them as Gods to be obeyed!

I only said that I would bond together the taps and waste on a plastic bath as I believe its safer. That does not include bonding from the taps to anywhere else in a bathroom if the supply pipes are in plastic.

Whilst on holiday on Mahe, I received a shock in the shower. On investigating I discovered 35v between the shower head pipework and the ( earthed ) waste. Checking further, I found that the pipework was correctly earthed to the supply neutral but the neutral was floating well above the natural earth due to load imbalances at the local transformer. Following that experience I hold strong views about bonding taps and waste together as it is the wet body worst case involved.

Tony Glazier

 

[ban-all-sheds]

I do not do electrical work in bathrooms because I do not have the right certificates yet. I work within the ( commonly thought ) limits of legality

http://www.opsi.gov.uk/si/si2004/20043210.htm

and particularly I do not argue with Building Inspectors, I treat them as Gods to be obeyed!

A great deal of anecdotal evidence is emerging that there are a number of LABCs (many? most??) who are exploiting the ignorance of their customers and indulging in sharp practice:

1) Charging people extra because they have chosen to subcontract electrical inspection and testing to a 3rd party. LABC Services, the umbrella organisation, have confirmed to me that LABCs are not allowed to charge extra in this way. Subcontracting is up to them, but the cost of it must come out of their fee.

or

2) Insisting that non-registered people themselves get the work inspected and tested by someone they regard as competent - it is quite clear that the legislation does not allow them to do this.

or

3) Pretending that non-registered people simply cannot do notifiable work at all.

I only said that I would bond together the taps and waste on a plastic bath as I believe its safer. That does not include bonding from the taps to anywhere else in a bathroom if the supply pipes are in plastic.

And what's the electrical reason for doing that? What does it accomplish? What does it prevent?

Whilst on holiday on Mahe, I received a shock in the shower. On investigating I discovered 35v between the shower head pipework and the ( earthed ) waste. Checking further, I found that the pipework was correctly earthed to the supply neutral but the neutral was floating well above the natural earth due to load imbalances at the local transformer. Following that experience I hold strong views about bonding taps and waste together as it is the wet body worst case involved.

If the shower pipework was metal, and the waste was metal, then these would be extraneous-conductive-parts, and (in the UK, if BS7671 was being observed) they would be bonded together.

If the shower pipework was not metal except the final visible parts for aesthetic reasons, then the fact that they were connected to neutral was responsible for the voltage you encountered, and if there had been no connection then there would have been no PD between the shower head and the waste. In the bathroom you describe, if you had bonded the waste and the non-earthed taps as you advocate, then you would actually have made things worse by providing more items that could be touched in order to get an electric shock.

Also, what does " that the pipework was correctly earthed to the supply neutral" mean? Was this a locally regenerated earth? Was it a TN-C-S system without PME? Was it a TN-C-S system with failed PMEs?
Is it relevant to UK practices?

 

[Agile]

"""2) Insisting that non-registered people themselves get the work inspected and tested by someone they regard as competent - it is quite clear that the legislation does not allow them to do this.

3) Pretending that non-registered people simply cannot do notifiable work at all. """

Those two statements cannot exist together. How do you suggest that a non-registered person can do notifiable work if:-

1. They cannot notify it themselves, being non registered.

2. It is not practically possible to get a registered person to test work for a third party because they have been advised by NICEIC & Co that they should not inspect work which they have not done.

I can only assume that you must be referring to the only solution I am aware of by prior notification to the LA, 1st fix inspection and completion inspection? I appreciate that is possible but for small jobs it is expensive and time wasting.

For some reason that I cannot now remember, that procedure is not available for work on the CU. In any case the Building Inspector's five day course stopped short of inspecting CUs. Perhaps thats the situation when they bring in sub-contractors?

Tony Glazier

 

[ban-all-sheds]

"""2) Insisting that non-registered people themselves get the work inspected and tested by someone they regard as competent - it is quite clear that the legislation does not allow them to do this.

3) Pretending that non-registered people simply cannot do notifiable work at all. """

Those two statements cannot exist together.

I never meant them to be read as (1) AND (2) AND (3) - I'll edit the post above to make it clearer.

How do you suggest that a non-registered person can do notifiable work if:-

1. They cannot notify it themselves, being non registered.

Of course non-registered people can notify work! Have you actually bothered to read the Statutory Instrument? If not then any further discussion is likely to fall into the category of me engaging in a battle of wits with an unarmed opponent....

2. It is not practically possible to get a registered person to test work for a third party because they have been advised by NICEIC & Co that they should not inspect work which they have not done.

Such advice from NICEIC is an illegal restraint of trade. NICIEC cannot stop their members from carrying out lawful work which they are competent to do, e.g. carrying out inspection & testing and issuing an I&T EIC.

I can only assume that you must be referring to the only solution I am aware of by prior notification to the LA, 1st fix inspection and completion inspection? I appreciate that is possible but for small jobs it is expensive and time wasting.

Indeed it is, but that is not something that affects its legitimacy.

For some reason that I cannot now remember, that procedure is not available for work on the CU.

Show me where in the legislation it says that.

In any case the Building Inspector's five day course stopped short of inspecting CUs. Perhaps thats the situation when they bring in sub-contractors?

Maybe it is They are at liberty to bring in subcontractors whenever they want, but they have to pay for them themselves, out of their fee.

 

[Agile]

""If not then any further discussion is likely to fall into the category of me engaging in a battle of wits with an unarmed opponent....""

I did not realise that I was engaging in a battle of wits! That being so I don't think I am doing so badly as an " unarmed opponent ".

That said, since we clearly agree on the vast majority of topics there is really no battle at all!

I will call the Ealing BCI when I find his card to see why he says that unregistered people cannot fit CUs. Unfortunately my office has been cleared up and I cannot find anything at the moment.

Tony Glazier

 

[mapj1]

Is this the Ealing Building control that believe you should cross bond in kitchens, despite the requirementhaving been dropped from the regs for the very good reason that it can cause more problems than it solves in many cases?
I'd suggest treating some BCOs, particularly those trying to lay down the law in areas outside their speciality, as being potential dictators that need their wings clipping from time to time. That said, most come over all fluffy and reasonable when faced with irrefutable evidence that they have 'misunderstood the position'