BAS, I am impressed. The seals are still intact! 
Advice please re: Duty of Supplier
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I think that's what "bonding" means to many flavours of mechanical engineer and technicians etc., and I'm sure that the average member of the public's understanding of "bonding" is far closer to that than to the technical sense in which it is used in relation to electrical installations. Ask Joe public if his water supply pipes are bonded, and he's quite likely to answer along the lines of "No, it's all done with compression joints"!
Kind Regards, John.
I would want to undertake an examination before being too sure; it's easy to hide the cut for the purpose opf a photo-shootBAS, I am impressed. The seals are still intact!
Kind Regards, John.
When my new electrical supply was installed in the cottage the DNO staff told me that my electrician ( that's me ) could use the provided "earth" terminal in the cut out for PME or provide an alternative earth using a ground rod.
It was also said somewhere in the discussion with the DNO that not all properties are suited for PME "earthing" and each should be considered on its own merits.
Which is god in my case as I am still in two minds which way to go. It is a stone wall cottage with conductive moist walls that do introduce extraneous potentials in the same way as service pipes do.
FACT.. A PME "earthed" back box will be at a different potential to the slightly conductive wall it is screwed into. As long as this difference is pure AC ( no residual DC component ) corrosion of the back box will be acceptable slow. But any diodic component in the earth and ground circuits that creates a DC component in the voltage difference between the PME "earth" and the wall and the rate of corrosion could become un-acceptable fast.
It was also said somewhere in the discussion with the DNO that not all properties are suited for PME "earthing" and each should be considered on its own merits.
Which is god in my case as I am still in two minds which way to go. It is a stone wall cottage with conductive moist walls that do introduce extraneous potentials in the same way as service pipes do.
FACT.. A PME "earthed" back box will be at a different potential to the slightly conductive wall it is screwed into. As long as this difference is pure AC ( no residual DC component ) corrosion of the back box will be acceptable slow. But any diodic component in the earth and ground circuits that creates a DC component in the voltage difference between the PME "earth" and the wall and the rate of corrosion could become un-acceptable fast.
BAS, I am impressed. The seals are still intact!
But in any event, my meter has a built-in isolator.
Would it be an extraneous conductive part when the DNO's supply is in use, and an earth rod when the generator is in use?
I think some of this silliness of terminology can perhaps be helped by realising that an earthing conductor coming from an earth rod very much is (per BS7671 definition), and always is, an extraneous-conductive-part when it enters the premises and so, like any other e-c-p, must be connected (bonded?
) to the MET!Kind Regards, John.
The biggest problem is the poor customer stuck in the middle!
We had one today, a customer rang in after an electrician had visited site, reporting no means of earthing.
Yep he should have converted it to TT.
One of our guys attended and we decided the network was PME, we decided to fit this and informed that customer that there was an earth now available. Customer was a bit unhappy when we refused to check the bonding and connect to the MET, but that they had to get their own electrical contractor in.
We had one today, a customer rang in after an electrician had visited site, reporting no means of earthing.
Yep he should have converted it to TT.
One of our guys attended and we decided the network was PME, we decided to fit this and informed that customer that there was an earth now available. Customer was a bit unhappy when we refused to check the bonding and connect to the MET, but that they had to get their own electrical contractor in.
Hmmm. These 'demarcations' are undoubtedly very frustrating to customers - so I suppose one should be thankful that there was not also a meter involved in this mix
As an outsider, in all senses, I can't help thinking that earthing and main bonding are so central to the safety of an electricity supply that a DNO should be prepared to (maybe even obliged to) sort them out in a situation such as you describe.Mind you. electricity is not the only service which suffers from serious customer frustrations due to demarcations. A colleague of mine recently had her water supply replaced, which involved digging up her drive. It took 'ages' (two or three weeks) to get the job finished (during most of which period there was a hazardous deep hole in her drive) due to the difficulty of co-ordinating the activities of four (or maybe even more) sets of people - diggers of holes, fillers-in of holes, replacers of pipes, connectors of pipes, inspectors of replaced pipes before they were covered up etc. etc. !
Kind Regards, John
Don't get me started on meters and suppliers,. that was the other good one of the day that had us all puzzled!
At the end of the day there has to be a line somewhere, in the above case we should have told the customer to get a TT earth fitted, as it did not have an earth. I decided it was possible for us to supply an earth that, legally, we don't need to.
Whoever asked the customer to ring us should have explained all this and ensured that all the bonding was adequate.
We do not, cannot work on private wiring
At the end of the day there has to be a line somewhere, in the above case we should have told the customer to get a TT earth fitted, as it did not have an earth. I decided it was possible for us to supply an earth that, legally, we don't need to.
Whoever asked the customer to ring us should have explained all this and ensured that all the bonding was adequate.
We do not, cannot work on private wiring
Yes, but is that not the problem? The "do not, and cannot" presumably relates to rules, which could be changed. You say that there has to be a line someone - but does there? Does there have to be a rigid 'line' - what about 'overlap'? We've discussed before (no need to repeat that discussion) the view of some that electricians should be trained and 'authorised' to pull most cutout fuses (and to recognise those they shoudn't touch). The corollary would be for DNO staff to be trained and authorised to do some types of work on the 'front end' and earthing/bonding of 'private' installations, if it formed a logical part of other work they were doing.
Without such 'versatility' there is a risk (perhaps already realised!) of a highly inefficient "how many (wo)men does it take to change a lighbulb" situation! Some degree of mutually-acceptable 'overlap' exists in many trades and professions, so I don't see why it couldn't work here - given a desire on the part of those involved!
Kind Regards, John.
As a DNO we are not allowed by law to operate as an electrical contractor! We do have limited opportunities to do some work on HV systems but under strict financial limits.
So are you suggesting DNOs should be installing bonding for free, that would start a good scam by customers getting us to do it.
Should we do a full inspection for nothing, repair any faults for nothing?
In our case locally we have one member of staff on a daily basis to attend to issues around the meter position, he wouldn't get to provide a 1 or 3 hour response (no choice we HAVE to attend faults in those timescales) in a lot of cases.
The easiest would be to say "you don't have an earth, we are not obliged to provide one, goodbye"
So are you suggesting DNOs should be installing bonding for free, that would start a good scam by customers getting us to do it.
Should we do a full inspection for nothing, repair any faults for nothing?
In our case locally we have one member of staff on a daily basis to attend to issues around the meter position, he wouldn't get to provide a 1 or 3 hour response (no choice we HAVE to attend faults in those timescales) in a lot of cases.
The easiest would be to say "you don't have an earth, we are not obliged to provide one, goodbye"
Sure, but that just one of the ('man-made') 'rules' I was talking about - that doesn't necessarily have to remain unchanged. As you realise, I'm not talking about what can/does happen in the present 'system' - I'm talking about what might be a better system.
I haven't suggested anything about who should pay (even though, ultimately, it obviously has to be the customer, however indirectly). That's something that would have to be worked out. If worked out 'properly and fairly' it ought to be cheaper for the customer to pay the DNO (wo)man who is already on site than having to call out another person.
Easiest for you, perhaps, but clearly not efficient as far as the customer (or the true overall cost, owever nadministered) is concerned.
Kind Regards, John.
Hey have no doubt what you say makes sense and before privatisation (which in part we were told was about improving customer service) we would have done exactly that!
But the politicians and civil servants wanted to improve things .............
In the case being discussed I should not have really allowed him to provide that earth terminal, but ...........
But the politicians and civil servants wanted to improve things .............
In the case being discussed I should not have really allowed him to provide that earth terminal, but ...........
Sorry to butt in - but a relevant/recent example.
Called to a property yesterday for an immersion heater fault. Subsequent investigations showed:-
(1) Suppliers meter broken
(2) Unconnected CU Earthing Conductor (there being no MET) in meter cupboard and no access to head without breaking the seals.
Young family with 16 month old baby. CU in question is in newly converted garage (about 1 year ago). Looks like original electrician asked for supplier to connect Earhing Conductor but this was not done.
As the head is the property of the electricity supplier and legally electricians are not allowed to touch it - who should connect the Earthing Conductor? And shouldn't this be done at the same time as the electricity supplier is replacing their meter (which is currently preventing the client of having any means of hot water)?
Since we are all law abiding - what is the real answer?
Regards
Called to a property yesterday for an immersion heater fault. Subsequent investigations showed:-
(1) Suppliers meter broken
(2) Unconnected CU Earthing Conductor (there being no MET) in meter cupboard and no access to head without breaking the seals.
Young family with 16 month old baby. CU in question is in newly converted garage (about 1 year ago). Looks like original electrician asked for supplier to connect Earhing Conductor but this was not done.
As the head is the property of the electricity supplier and legally electricians are not allowed to touch it - who should connect the Earthing Conductor? And shouldn't this be done at the same time as the electricity supplier is replacing their meter (which is currently preventing the client of having any means of hot water)?
Since we are all law abiding - what is the real answer?
Regards
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