Earthing plastic/ PVC Pipes and mixture of Metal Pipes

[EFLImpudence]

he suggested that i bond all pipes work together with 10mm earth wire,

Agreed. Not necessary.

 

[JohnW2]

Just a 'holding reply' (things I hate receiving)! .... You ask some interesting and valid questions. I am currently thinking as deeply as I can about some uncertainties and 'cans of worms' in my mind, and will attempt to respond soon if/when my thinking achieves anything - hopefully tomorrow! ...

To avoid confusion/complaints, I've started a new thread (here)

Kind Regards, John

 

[Mikefromlondon]

Thanks guys, but I did have my doubts, he may well require it, so i went prepared, took with me 3meter
length of 10mil earth conductor and 5 earthing clamps, as soon as he suggested that, i showed him this thread but he didn't read all of it but insisted that in the event of any electrical appliance in utility room such as iron lead, washing machine lead or any other flex with bad insulation or nicks etc comes into contact with any of the copper pipe works, it may carry fault currents into the bathroom upstairs where the occupants in the bath may get electrocuted if he touched bath or sink tap whilst touching the CH radiator, however, it is easy to see that in fact all pipework is earthed or at the same potential through the boiler chassis, since all pipes also connect to the boiler including the gas mains which is also earth bonded at the meter cupboard where both electric and gas meters are. Yes I agree it was not needed but I was not going to argue with guy as I just bonding them them together took me about half an hour, the fact there was a peculiar fault that was not apparent before I also replaced 2 MCBs with RCBOs, this was a bit of a brain teaser, but luckily it took me a while to sort this out

Here is what I found happened:

There were two seperate 6A breakers one for Ground floor lighting, and One for First Floor lighting , I took these out and wired up 2 new RCBOs, before the electrician arrived, he had agreed for me to carry out these works and he will check it and if satisfied only then issue the EICR.

Upon wiring the two circuits in two seperate RCBOs, switched power back on, all went good as expected, downstairs lights all checked no tripping,

Went upstairs checked all lights and all but one started to trip BOTH RCBOs........I went into panic mode! WTF ! Why both RCBOs were tripping as soon as I switched one two way light circuit on in upper hallway!

I took the lamp out and no problem if I switch on this two way circuit, but as soon as I plug a light bulb back in it trips both RCBO!

None of the other lights in any of the other rooms including the bathroom where I fitted a new IP44 rated LED light fitting.

It took me a while to figure out what might be causing the problem, I remember a tenant one had an electrician fit a TV Aerial booster amplifier in the loft, to give stronger TV signals, I gave him the permission for his electrician or aerial installer to fit this amplifier, but he wired it into the nearest ceiling rose as it draws mili amps so being on lighting circuit was never an issue, but I suspected this may be causing the problem. I ripped it out as no one is using terrestrial TV signals, current tenant is hooked on Sky dish and broadband TV, this made no difference what so ever,

With the before MCB only set up there never was any issue of any of the MCB's tripping, but now I was having a weird issue, it was not just tripping the first floor RCBO but both of them.

I had to sit in one corner and get a plain paper from the tenant and started draw two way switch and what can cause such a problem where both RCBO's trip, and I could then see where the problem could be and I was right, I isolated a few wires in the switches, and sussed the problem, and just in time managed to get it sorted out so no more tripping when you switched on this hallway light

So when the light in the hallway is off, both RCBOs are ON, all room lights come on on both ground floor and on First floor except just one light in this upper hallway, so no matter which switch you use, as soon as you try to switch on this light it trips out both RCBOs, so a bit of a brain teaser for you guys.

I even thought I might have cross wired neutrals in the RCBO's so I took them out and reversed the neutrals and it made the situation worst and it tripped as soon as you switch on any light either on GF or on FF.

Further more if I had not used two seperate RCBOs instead used a second RCD for both lighting circuit but independently protected by two seperate 6A MCBs , this scenario would not have occurred and would have gone unnoticed.

 

[JohnW2]

.... insisted that in the event of any electrical appliance in utility room such as iron lead, washing machine lead or any other flex with bad insulation or nicks etc comes into contact with any of the copper pipe works, it may carry fault currents into the bathroom upstairs where the occupants in the bath may get electrocuted if he touched bath or sink tap whilst touching the CH radiator, ...

As I explained yesterday, one can present an opposite argument - that if one touched something live ("such as iron lead, washing machine lead or any other flex with bad insulation or nicks etc.") and simultaneously touched a pipe, radiator or tap one would get a sock if that pipe/radiator/tap were earthed, but not if it were not earthed (if that were possible, which virtually never is the case). However, in any event, as i said yesterday and as you say now ...

... however, it is easy to see that in fact all pipework is earthed or at the same potential through the boiler chassis, since all pipes also connect to the boiler including the gas mains which is also earth bonded at the meter cupboard where both electric and gas meters are.

Quite so. As I said, any pipework/radiators/taps/whatever to do with CH and/or HW will inevitable be earthed. The only possible exception are cold water pipes - if all storage/header tanks are plastic, there are no metal mixer taps and no places where H & C taps are both attached to the same metal tank etc., then it is possible that the cold pipework (and taps etc.) will remain unearthed. However, ironically, such a cold water pipe does not feature amongst the pipes in the vicinity of a boiler which plumbers (but not usually electricians) love to bond together - so they may well miss the one that (in some people's eyes) might actually 'benefit' from being earthed!

What worries me a bit about guys like yours is that he seems to only 'half understand', and doesn't seem to understand at all that what he is insisting on is something that is not required by the regulations - which would leave me a little concerned about to what other gaps/confusions might exist in his knowledge and/or understanding.

Kind Regards, John

 

[EFLImpudence]

Also -

It is not correct to demand that some parts be bonded because they are not earthed.

Parts might only require bonding because they are earthed.

 

[Mikefromlondon]

Very true John, and Efl, but we all must learn to walk before we can run, we are all getting old, retiring, new generation are coming into the scene, with less experience, this electrician was relatively young man, and I could not afford to delay getting an ECIR as now required by law, so had to do what he asked for, but over time these young men will gain more experience and get better knowledge, and understanding, but better to be safe than to be sorry, if the supply (water) was metal and bonded to earth at incoming suppliers earth, then definitely it would not have been an issue, or not required at all, but since danger can exist if say the boiler was being replaced or say if gas pipe had to be cut for some reason like say to add a "Tee " section to branch off gas for a gas cooker, it is during this time if a Gas man does not bond the pipes before cutting the pipe work, that if any fault currents occur after or during cutting, it could prove lethal, so best to be on the safe side have multiple earthing points should one go wrong you have a back up. Thats just my opinion, not necessarily a must.

Glad to see you guys have made through waves of covid..... stay safe.

 

[Mikefromlondon]

Any ways time is money, I certainly don't want you to think why both RCBOs were tripping when a specific light was being switched on in the upper Hall way, which also happened to be a two way light, which in itself is irrelevant, it could have been a single switched light, but the problem was its neutral was being borrowed from the neutral from the ground floor lighting circuit, such that every time you switched it on, the live current passing through One RCBO did not return through it but through the other RCBO, so knocking both of them out. I quickly ran a neutral lead from another ceiling light in an adjoining room and wired it to this hallway ceiling rose, and disconnected the one from the ground floor and taped it up, God knows who wired this mixing neutrals.

 

[Mikefromlondon]

But.....Thanks for your help in helping me.

 

[JohnW2]

Very true John, and Efl, but we all must learn to walk before we can run, we are all getting old, retiring, new generation are coming into the scene, with less experience, this electrician was relatively young man, and I could not afford to delay getting an ECIR as now required by law, so had to do what he asked for, but over time these young men will gain more experience and get better knowledge, and understanding, but better to be safe than to be sorry ...

All true. Knowledge, competence and experience progressively increase throughout any career. However, one has the right to expect that anyone practising, in any field (and particularly if practising alone) is adequately knowledgeable and competent to do things properly and safely (particularly give that the vast number of customers/whatever will 'know no better') - think doctors or airline pilots

In your case, his lack of knowledge/undertsnading (particularly of the regulations) led to what many would regard as 'erring on the side of safety'. However, as I thought I implied, my concerns would be that other 'lacks' might cause such a person to sometimes err in the other direction!

... if the supply (water) was metal and bonded to earth at incoming suppliers earth, then definitely it would not have been an issue, or not required at all ....

That's an interesting one. I obviously cannot know what would be the case with your electrician, but the plumbers who go around 'bonding' countless pipes together in the vicinity of boilers, or in airing cupboards, will generally insist on doing that even when there was an incoming metal water pipe that was properly bonded to the installation's earth! ... and, in any event, as I think we have agreed, that's only relevant to cold water pipes, since the CH and HW ones will (if all copper) inevitably be connected to the installation's earth.

Glad to see you guys have made through waves of covid..... stay safe.

... and glad to see that you obviously have, too. Not only have we so far survived Covid but we have also so far survived our second doses of AZ vaccine, albeit less than 2 weeks ago You keep safe, too.

Kind Regards, John

 

[SUNRAY]

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