Earth Loop
- Thread starter Oxia
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Yes, the lower the better, up to a point.
What did he say it should be?
May be he did say "bad", but not in relation to the reading? Could something else have been bad? No PE Bonding to the gas or water pipes, maybe?
No RCD on TT supply?
What did he say it should be?
May be he did say "bad", but not in relation to the reading? Could something else have been bad? No PE Bonding to the gas or water pipes, maybe?
No RCD on TT supply?
As has been said, in general the lower the better.
Where was his connecting his meter when he conducted this test - to a socket or somewhere close to the consumer unit or meter? If the former, he might have felt that 0.16Ω was too low to be very credible, since just a few metres of cable within your house would account for much of that figure, before one even started thinking about the cables between your house and the substation/transformer. However, if it were 'too low to be credible', the problem would really be with his measurement/meter, not your installation, so I'm a bit confused!
As has been suggested, I wonder if you misunderstood and that was saying that something other than the loop impedance was 'bad'? Did he suggest that anything needed doing to address this 'badness'?
Whatever, particularly given that he is a friend of yours, is not the simplest answer to ask him to clarify what he meant?
Kind Regards, John
Need more information, 0.16Ω is below the maximum measured Zs for the most common protective devices used normal socket circuits.
What is the supply type?
What is the fuse/MCB protecting the circuit?
Is the circuit a ring or a radial?
What is the supply type?
What is the fuse/MCB protecting the circuit?
Is the circuit a ring or a radial?
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We would certainly need more information if we were to try to help - but, as I said, the obvious course is for the OP to ask his friend - since the best any of us is likely to manage would be speculation. As for your questions, we don't even know that it was a Zs measurent of a ciruit - it might have been a Ze (hence my earlier question).
Kind Regards, John
sorry for the late reply, I asked him again and he said on the ring final he got 0.60 ohms (fine) then when he removed the consumer unit cover and tested the main earth to live/neutral (earth removed from CU to prevent any crossovers etc) he got 0.14 ohms
he said that was bad for PME and should be reported to DNO
he also reported that my voltage was 256.4v-258.0v
he said that was bad for PME and should be reported to DNO
he also reported that my voltage was 256.4v-258.0v
That still makes little sense to me. It's well under the maximum normally quoted for PME, so I don't know why he thinks it's 'bad'. As has been suggested before, next time ask him what he thinks it should be!
As you've been told, that's a little above the maximum of what it should be (253V). It probably should be checked again sometime, but if it's persistently over 253V, then the DNO are the ones to tell. With that low earth loop impedance and a high voltage, it sounds as if you're probably close to the transformer/'substation' - is that the case?
Kind Regards, John
The transformer is across the road from me, I guessed the PME bit because the earth cable comes from the side of the service head. Could I be wrong?
That sounds pretty close.
It sounds as if you are probably right.
Kind Regards, John
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The Ze is fine.
But the voltage is, as has been said, too high.
Out of interest, did he say what he thought the Ze should be?
But the voltage is, as has been said, too high.
Out of interest, did he say what he thought the Ze should be?
Maybe he means bad as in good?
"Your Ze is well bad innit"
"Your Ze is well bad innit"
That would certainly make more sense than real 'bad'
If he truly meant bad, I couldn't even start to guess whether he was thinking that it was too high or 'too low'!Kind Regards, John
Maybe, maybe not. As the earth is from the electricity supplier it will be TN-S or TN-CS (PME), the former having a max figure of 0.8Ω so either way it sounds OK.
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