Agile said:
""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!
mikegray said:
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?