Hi, done some testing on last job, continuity of CPC, Continuity of final ring , insulation resistance , RCD etc. I had no problems.  My problem was with the ELI test for the lighting circuit, for the ring I removed all the 'loads' connected the Fluke 1653 using the plug and there is a reading in every socket.  For the lighting (radial) I removed the bulbs and by - passed dimmers, I could not get a proper reading, I don't mean the value, but the process confused me. I looked at the GN3, Amicus testing book, OSG etc. they all talk more about the External loop (Ze) than Zs. Can someone explain the steps for this test, what to do before, where to connect the probs (which one of them) and in which part of the circuit, I probably know the procedure but I can't see it in practice. Thanks
Albert

Hi Albert

Assuming you're talking about Earth Fault Loop Impedance (EFLI), then it's really not that hard to do, obviously there is external impedance (Ze) and system impedance (Zs) which is the impedance of your circuit and external loop impedance..

Don't know what meter your using but most Phase-Earth Loop testers require a neutral to operate, you should have a 3-test lead set Red/Black/Green or similar, firstly the earth probe/clip needs to be clipped on to the earth, then using the neutral and phase probe, hold them onto the neutral and phase terminals in that order, you want to test at the furtherst point in the circuit as your looking for the highest reading, in most situations you will be unable to tell where the furthest point is and therefor you would have to measure at all available points in the circuit

If your meter has 20ohms setting, turn to this, if it doesnt it's likely autoranging and will set it's self to the closest ohms range

It sounds like you have all the books, the best one to read is the electricians guide or on-site guide, the guidance notes are good, but for basic testing the first two are probably what you need

Alternatively you can calculate the Zs by using the following values, Zs = Ze + (R1+R2), if you don't feel competent to do the live test then It's probably best you leave it until you feel you can do it safely, if you could find someone who can show you how to do it that would be even better.

The live tests can be quite hazardoures and pose a risk to persons and property if not conducted correctly, theres a risk of pipework becoming live if if the installation is not up to scratch

[quote author=akuk  link=1119947508/0#3 date=1119956683]I think that I cracked most of the tests and have a good understanding of the procedures and results. [/quote]
That's great news

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You've pretty much got it there Albert, the neutral is only for the instrument to work, it is not actualy used to conduct the test as such, the important thing is that you have 3-leads aswel as your 13A plug, you would use the 13A plug as you have done, on ring circuit's and the like, and then use the 3-lead test for testing at wiring accesories, consumer unit etc

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Yep, I don't use a 1652, but I'm getting my head around it slowly  

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ooo you lucky thing, you're be getting assessed before me, frigging courses!

I can't comment much on the probes as I don't use the 1652, the green/earth clip is the one that goes on first, then you should only have to hold the 2 other probes

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The continuity of CPC can be done as just an R2 test where you connect a long lead to the earth block at the board, and then connect it to one probe, connect other to an earth point at a light or similar, it's alot of messing about, so we do R1+R2 which is where we bridge phase to earth at the board, or at a light, and then test between phase and earth at the other end, this is then our phase and earth value

[quote author=akuk  link=1119947508/0#5 date=1119958974], I am not worried about the colours, I am asking how to connect 3 of them with 2 handa? [/quote]

The earth clip SHOULD hold itself, but most croc clips tend to fall off if you move the cable slightly.  In a ceiling rose, you can often get away with ONE hand for the earth croc clip, and P & N probes...space the probes with your fingers...there's an art to it!!  You need to do this if you need a seperate hand to operate the test sw on the meter (balanced on the top of your stepladders)!!

[quote author=akuk  link=1119947508/0#5 date=1119958974] what I ment was that cpc to phase at the furthest point will give R1+R2 and not r1+r2, and I'm sure that you know that...
[/quote]
Yes I'm well aware, read what I said again

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The colours are just as important as using fused test probes correctly, as I've already said you clip the earth on first, if the earth doesn’t stay on then you're either not doing it properly, or the probes on the 1653 are really bad!

Sometimes the clips won't go on terminals, if this happens best thing to do is to disconnect the earth cable and clip straight on, however this could be difficult if you have 2-3 CPC's

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No requirements, we test circuit's individually for impedance, not as a whole

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This is something you will get used to, I can't say it's easy because it's not always, but you're have to practice, the main thing is the earth crocodile clip, if this isnt working then you're wasting you're time

[quote author=akuk  link=1119947508/0#3 date=1119956683] I had to use the fly frobs, I used the earth and phase, and could not get sense out of it, than I started to suspect that the Fluke 1653 needs neutral for this test [/quote]

On my Fluke 1652 there are lcd indicators in the screen telling you what cables need to be connected to it for each particular test.  This makes sure you always use the right test cables.