Very high Ze

[charlie76]

Just put a extract fan in for someone fed off lighting circuit. Came to do my testing and found Ze was reading 11ohms :nonod:. Didnt even bother checking anything else, disconnected it and told the client to get DNO out to check. To be honest though it looks like the cowboy who rewired it in the last year or so has put his own BS951 clamp on (It is TNCS) but it looks like its not even touching the lead sheath. I didnt want to get involved with touching that mess.

Whats the best advice in this situation? I am thinking of saying sorry but you will have to leave it isolated until you get the earth sorted and then go back an do my testing and liven it up. Chances are he'll try and worm his way out of paying.

 

[davesparks]

Why didn't you bother doing the rest of the testing? You could have done everything except the Zs and then had a much easier time of it when you return to connect and certify the job.

Plus it will be very awkward if you find something else wrong when you do the testing now, that would certainly help to earn you a bad reputation.

Are you sure it's a TNCS?

What did the DNO say when you reported this fault to them?


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[charlie76]

Why didn't you bother doing the rest of the testing? You could have done everything except the Zs and then had a much easier time of it when you return to connect and certify the job.

Plus it will be very awkward if you find something else wrong when you do the testing now, that would certainly help to earn you a bad reputation.

Are you sure it's a TNCS?

What did the DNO say when you reported this fault to them?


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DNO not been out yet. I have told the customer he needs to get them out. I could nip back tomorrow and do the rest of the testing. Tennant is away anyway so I guess I could get it done. Your right Dave, looking at the state of the install (No idents on MCB's no earth sleeving in lighting, messy in CU) it could well have other issues. I'll check it out in the morning.

Yes it is a TNC-S

 

[charlie76]

However that aside, What I was after is what you would do in that situation. Leave it isolated?

 

[davesparks]

DNO not been out yet. I have told the customer he needs to get them out. I could nip back tomorrow and do the rest of the testing. Tennant is away anyway so I guess I could get it done. Your right Dave, looking at the state of the install (No idents on MCB's no earth sleeving in lighting, messy in CU) it could well have other issues. I'll check it out in the morning.

So you didn't speak to the DNO yourself? A that really the best plan?

 

[davesparks]

However that aside, What I was after is what you would do in that situation. Leave it isolated?

Without the rest of the test results I don't know what I would do!

If the rest of the circuit passes, including the RCD tripping times then I would be happy to rely on the RCD for fault protection in the short term.

 

[charlie76]

Without the rest of the test results I don't know what I would do!

If the rest of the circuit passes, including the RCD tripping times then I would be happy to rely on the RCD for fault protection in the short term.

Funnily enough, I did do the RCD tripping times and they were fine. Checked PSC impedance also and that was fine.

 

[sparky1508]

Just put a extract fan in for someone fed off lighting circuit. Came to do my testing and found Ze was reading 11ohms :nonod:. Didnt even bother checking anything else, disconnected it and told the client to get DNO out to check. To be honest though it looks like the cowboy who rewired it in the last year or so has put his own BS951 clamp on (It is TNCS) but it looks like its not even touching the lead sheath. I didnt want to get involved with touching that mess.

Whats the best advice in this situation? I am thinking of saying sorry but you will have to leave it isolated until you get the earth sorted and then go back an do my testing and liven it up. Chances are he'll try and worm his way out of paying.

If it's got a lead sheath then it's TN-S not TN-C-S.

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[charlie76]

If it's got a lead sheath then it's TN-S not TN-C-S.

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Sorry slip of tongue/keyboard/brain and too much rum tonight it is TNS. Hence the 951 clamp (albeit wrongly so) on the sheath.

 

[davesparks]

Did you try getting a Ze directly on the lead?

I did an EICR today where the Ze tested on the sheath was 0.12 ohm and the Ze on the dodgy 951 clamp at its terminal was 0.18ohm


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[charlie76]

No, my bad. Just what I was thinking I tested at the clamp only. So i'll check the lead tomorrow. I spoke to the client/landlord and it sounds like he got the rewire done on the cheap, no testing etc. My first comment to him was this cant have been tested and he sheepishly told me he didn't get a cert. I'll check the lead tomorrow before he calls out the DNO but if that meters out ok where would I go from there. The 951 shouldn't be on the sheath anyway and now I know its a sh|tty install.

 

[davesparks]

No, my bad. Just what I was thinking I tested at the clamp only. So i'll check the lead tomorrow. I spoke to the client/landlord and it sounds like he got the rewire done on the cheap, no testing etc. My first comment to him was this cant have been tested and he sheepishly told me he didn't get a cert. I'll check the lead tomorrow before he calls out the DNO but if that meters out ok where would I go from there. The 951 shouldn't be on the sheath anyway and now I know its a sh|tty install.

Don't worry too much about the value on the sheath, it won't make the situation right either way, I just find it interesting to get as much information as possible when encountering these problems.
If you can get post the reading on the sheath up here I would be interested to know what the difference is.

Better that you call the DNO, then you can actually get your point across rather than Chinese whispers