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Im with guitarist on this one, DNO need to sort it but i know what they will say. I went to a job with a brand new cutout installed and when arrived surprise there was no earth installed! Nice one DNO..............
 
I think from the fact that he took a reading at a socket of 0.30 so i think he was saying it should be less at the MET.
Although i would take out the bonding conductors to rule out parallel paths providing good earth!
 
if this were me....i would get a Ze in the normal way (disconnect main earthing from MET)....leave that `earthing clamp` well alone....just check its secure...thats all....you have already proven a low impedance (Zs)....it aint your property....and it aint the customers either....ring the DNO by all means....all they`l say is `you`ll have to rod it`...or words to that effect....
 
How do you know the DNO didnt leave it like that? I have seen plenty of them like that, which DNO class as safe??
The new cutout was installed on existing installation as old cutout had burnt out, it was TNS but they forgot to put a earth on it and let house without an earth.
 
Yes Sparks1973 and Snapester, I've seen loads like that too guys, none of which have been done by the DNO though
 
Yes Sparks1973 and Snapester, I've seen loads like that too guys, none of which have been done by the DNO though
oh it`l be have a go heros alrite Trev..lol....but the proof of whether its good for continued service will be:
1) the visual.....is it secure
2) the test....whats the Ze
 
That clamp looks a bit lightweight to me. I would just put 40Amps through it with the loop impedance tester and see if it's good.
 
No way would I convert tns to tt just because the dno cant be arsed spending 10mins reconnecting their own earth strap.
Get the homeowner to insist on a repair visit.
If it's a legitimately done TN-S then I wouldn't change it to a TT either Biff but the legitimacy or otherwise of that TN-S has yet to be confirmed. If it should be a TN-S then I too would be insisting that the DNO come out to maintain the earth that they are legally obliged to
 
yeah but for how long?....a high loop test is a very short duration test....wont affect that......

Yep, it's a pulse test but if it gives similar readings at 40A or more as it does on a low current test then it should be stable under general fault conditions.
 
I would contact the DNO and tell them that there seems to be a problem with the earth that they have supplied. If they ask for details just tell them that it appears that the connection may be loose.

I've tried by enquiry to find out what the earthing system is used at properties in the past to no success as they apparently do not hold these records??? Now I find that bizarre considering they have a responsibility to maintain their equipment. Now if they provide an earth then they'll have to attend... They'll soon tell you if they do not provide an earth to that property.

I would play dumb in this instance and explain that they have definitely put an earth on the sheath and that it's a TNS supply. I would not tell them anything about it being an earth clamp, just mention the clamp looks loose and see if you can at least get them to attend.

If they know for a fact that they do not supply an earth to that property then you'll have to explain to your client that they will need to pay you to install a rod to make it a TT system. Failing that, walk away. Providing you have not already commenced work in the property because if you have you'll be in the s*** as it will be your responsibility!
 
Yep, it's a pulse test but if it gives similar readings at 40A or more as it does on a low current test then it should be stable under general fault conditions.

Unfortunately , with a Zs of 0.4 he'll have a fault current of at least 575A lol.
 
Yes it's not the best but at least it's an acceptable value, I admit I have done such a clamp the other week on a job with no earth, it was impossible to TT so I just tapped onto the sheath! Whoops...... It happens but at least they had a working earth with a decent reading instead of no earth! Sometimes you have to do things that are politically incorrect!
 
I would contact the DNO and tell them that there seems to be a problem with the earth that they have supplied. If they ask for details just tell them that it appears that the connection may be loose.

I've tried by enquiry to find out what the earthing system is used at properties in the past to no success as they apparently do not hold these records??? Now I find that bizarre considering they have a responsibility to maintain their equipment. Now if they provide an earth then they'll have to attend... They'll soon tell you if they do not provide an earth to that property.

I would play dumb in this instance and explain that they have definitely put an earth on the sheath and that it's a TNS supply. I would not tell them anything about it being an earth clamp, just mention the clamp looks loose and see if you can at least get them to attend.

If they know for a fact that they do not supply an earth to that property then you'll have to explain to your client that they will need to pay you to install a rod to make it a TT system. Failing that, walk away. Providing you have not already commenced work in the property because if you have you'll be in the s*** as it will be your responsibility!
wont work...they keep records of what installation/head is what (TN-S, TN-C-S)
 

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