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See Chris Kitcher's reference book :Dont think you'll find these particular tests in any reference books will you ?
Discuss Loop Impedance reading in the UK Electrical Forum area at ElectriciansForums.net
See Chris Kitcher's reference book :Dont think you'll find these particular tests in any reference books will you ?
It is one factor, but even then wiggling the probes/clips on low Z systems usually gets a slightly lower value.something like that. the higher current helps to get past tarnished contacts, that's why low current test often gives slightly different results. ( well that's my theory, anyway ).
Hi
I bought a holiday lodge last month and decided to test the circuits to see how they measured. The lodge itself is fed from a central point in the holiday village by a 16mm PVCSWA. The main earth wire terminates into a MET it looks to be a 10mm earth that is crimped onto the incoming earth, I cannot see what its crimped onto as the head the mains terminated into prevents this. Anyway I carried out the the normal tests on the circuits R1 R2 RN and these tested all within the expected parameters as an example the one of the rings measured R1.24 RN.24 R2 .39 and R1/R2 .25.
The other circuits all tested within expected parameters. The Ze measured .6, however when I powered up and did a Earth Fault loop impedance test the machine measured 23 ohms, this was repeated on all the sockets and the same measurement. Assistance required please as to the possible reason (s) for this.
He said 0.6 tns?Do you know the earthing arrangement, you say you cannot see what the earth is attached too so could it be a TT earth and the rod has resistance of around 23ohms
Did he, whoops my mistakeHe said 0.6 tns?
Guys, alIt is one factor, but even then wiggling the probes/clips on low Z systems usually gets a slightly lower value.
More fundamentally the bigger the test current the larger the delta-V, and so it is easier to measure that and reject the wobbles on the supply that are usually there. For example, if test current is 20A then 0.3 ohms Zs is going to show a 6V change - easy to spot on 230V.
But if the test current is only 15mA to avoid tripping a RCD then you are trying to see a 4.5mV change in 230V or 0.002% which is why MFT take a long time to switch it on/off over and over so the supply noise gets averaged out but the disturbance reinforced.
Hi There,Do you know the earthing arrangement, you say you cannot see what the earth is attached too so could it be a TT earth and the rod has resistance of around 23ohms
Yes sorry i misread it, and somehow missed the 0.6ohm ze part, ignore me !Guys, al
Hi There,
I measured the Ze and it was .6 so I would assume not a TT, I have asked the facility manager the question to confirm it.
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