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Posted By Topic: Best test methods and order

OctaneOutlaw
Nov 04 2018 16:35

Im just curious with a few things about testing, I don\'t really understand correct circuit connections but I think I have my head around basically everything else

Pretty much I\'m just making this post as I\'m interested in what people believe are the best and most effective ways to complete the required tests (as I know some have multiple ways of doing so) and also what order you choose to complete them in

I have had a decent read of section 8 of 3000 and 3017 but just wanted to know how similar things are in the real world compared to this? (Obviously while still meeting all the requirements)

Let me know what you do/think and any explanation, detail is appreciated, I want to make sure I\'m doing everything to its full effect

Thanks
   

mowgli
Nov 04 2018 19:49

Testing circuit connections make yourself one of these. Cheap as chips
   

OctaneOutlaw
Nov 04 2018 20:05

Interesting, what is it? Haha

How does it work and how do I make one?
   

mowgli
Nov 04 2018 20:24

It\'s a few wires and two resistors.

Check 3017 but basically disconnect phase and neutral of the circuit under test at the board and connect the resistors. You measure 5, 10 or 15ohms at remote points to confirm the correct connections back to the board.
   

mowgli
Nov 04 2018 20:27

BTW it was given to me during pre-trade training. We all made one then they gave us these premade ones to keep.
   

Tommy
Nov 05 2018 17:40

Really good question I will also be interested to see what others think on this
   

jasmoon123
Nov 05 2018 18:28

A good way to understand \'Correct Circuit Connections\' test (and why the resistors are used) is to understand what it is testing for.

The test is identifying if the Neutral & Earth are transposed, if the Active & Neutral belong to the same circuit, and if the Active & Earth are transposed.

If you now run back through the testing method of using the resistors and confirm that this method identifies the 3x possible wiring faults.

Note that this test is different to the Polarity test.
   

Satobsat
Nov 05 2018 20:11

1)Main switch off, locked and tagged

2)Prove test prove for isolation Fluke multi-meter

3)Visual Eyes

4)Mechanical Pull,push and jiggle cable connections

5)Earthing Kyoritsu Analogue IR tester on low ohms scale

I use an extension lead with no plug on one end. Connect it to active, earth and neutral bars. MEN link out. Make sure all RCD protected MCBs are off but RCDs and other MCBs are on. This will give me neutral and earth polarity at each socket and active, neutral and earth polarity at any fixed wired appliance you want to test. Kyoritsu Analogue IR tester on low ohms scale


6)Equipotential bonding Kyoritsu Analogue IR tester on low ohms scale

Carried out at same time as test 3.


7)Insulation Resistance Kyoritsu Analogue IR tester

Testing installation insulation resistance, all control switches, RCDs and MCBs on, between live conductors and earth.


8)Correct circuit connections

Using a multi-meter on the ohms setting, test between all RCD protected circuits with all RCDs and all MCBs switched off, test between non RCD protected circuits, test between non RCD protected circuits and RCD protected circuits. Turn on all RCDs test between wiring after main switch and all circuits. Look out for low ohm readings indicating interconnection of circuits anything lower than 20 to 30 ohms could be suspect. It may be necessary to disconnect the neutrals from the neutral bar for equipment like large motors and transformers if testing between different circuits supplying them as their windings will have a low resistance reading.

9)Refit Men Link and turn main switch back on

10)Polarity Fluke Multi-meter or Fluke Multi-function Tester

11)EFLI Fluke Multi-function Tester

12)RCD Fluke Multi-function Tester

Test done on AC voltage setting to check RCD is wired correctly with regards to input A&N and output A&N then RCD timing tests, setting based on what type of RCD it is.

Correct circuit connections are proved in steps 3,5,6,8 and 10 plus most EFLI testers will show an A-N or A-E transposition fault before you even hit the test button. Also if there is an interconnection of any circuits on different RCDs more than one RCD will trip when tested. Correct circuit connections should not be an issue if you follow this procedure.

There is much more involved depending on what you are doing or what type of equipment is installed this just the basics of a domestic or small commercial installation, I also did not mention the testing of mains. Section 8 of 3000 goes into more detail.



   

AlecK
Nov 05 2018 20:18

All good stuff, but only dealing with part of it (and mostly dealing with polarity rather than CCC). There are 2 required outcomes set by 8.3.8.1.
- no short circuit (ie from any conductor of circuit under test to any conductor of any circuit including same circuit)
- PECs do not carry load current under normal (non-fault) conditions.

Basically tou need to IR test every possible combination of conductors to prove the first. And you have to have correct polarity plus not have N-E links in DBs to be sure of the second.

The main thing to understand is that all these tests are inter-related, and the validity of any test result depends on all other test results of all other types of test being OK.

Eg if you haven\'t actually proved the continuity of earth conductors to all points, your IR tests will not be valid (because you\'ve only tested to part of, instead of all of, the earthing system.
And unless you by-pass every PIR sensor, contactor, etc; you haven\'t IR tested ALL of the actives to earth. Let alone the neutrals.
   

Satobsat
Nov 05 2018 20:55

There is so much you can say about cccs. I recall coming across a two story house that had the two upstairs landing light fittings on different neutrals which meant with fluorescent lamps installed the lamp in one fitting worked whilst the other just flashed, but when an incandescent was fitted it tripped the RCD in the main SWB that was protecting the upstairs sub board which was the board the light circuit was fed from. Two neutrals one from the upstairs board to one fitting and one from the downstairs board to the other fitting. Both fittings less than 3 meters apart. Bodged rewire by another electrician.


\"And unless you by-pass every PIR sensor, contactor, etc; you haven\'t IR tested ALL of the actives to earth. Let alone the neutrals.\"

I gather you mean relays, contactors and ssds inside equipment that disconnect a switched wire to another piece of equipment? Do these not get tested when IR testing all live conductors (neutral is regarded as a live conductor) to earth?
   

AlecK
Nov 06 2018 08:51

Was just an example of how the various \"types\" of test are actually not separate but inter-related. Not directly related to CCC. Each type has it\'s own declared objective (though of course earth continuity & EFLI are really two aspects of same functionality.

The order of carrying out tests that is suggested in the standards is not a requirement; we can do them in whatever order we like as long as the combined effect of all tests proves all requirements have been met. But that order has been found to be, in most cases, the most efficient. Whatever order we do them in; a single fail on any test of any type means some of the earlier tests\' results may be invalid.


Yes testing \"all-live\" to e is an option for I.R. testing. And for some circuits, IF there\'s a suitable load providing a path between A & N then the section of A downstream of a switch may be adequately tested. Eg a resistive load such as a heating element or an incandescent lamp. If there\'s no load, obviously we have to set the switch to \"on\" (or if it\'s a relay, bypass it). For some of today\'s loads, the internal circuitry may block the d.c. we use for IR testing. So we can\'t just rely on using the \"all live to E\" test method for this.
Similarly with 2-way & intermediate switching we have to test both lots of \"strap[\" wiring; so need to do a 2nd test after changing one of the \"end\" 2-way switches to the other position (NOT one of the intermediates).

The other thing to recognise is that while \"all-live to E\" is good for avoiding damage to the connected loads form the 500 v test voltage; under the CCC heading we still have to prove no short circuit between A & N - which we can\'t do with the load in circuit even though for this (even though we don\'t need to be using 500V).

Mowgli\'s set of test resistors is an excellent tool, and of course the actual values don\'t matter as long as they are known and not the same. And at the same time as proving no transposition that could energise exposed conductive parts (a required CCC result); it also is part of testing polarity.

I have an \"advanced\" version that uses a battery to send a pulsed signal to a special receiver fitted with R & G LEDs; which works nicely as long as there\'s no loads connected.

The test methods given in \"3017\" are mostly for testing a single circuit. Scaling up to multiple circuits we can make efficiency gains by combining tests. But we need to make certain that doing so doesn\'t invalidate the results.

The last thing we want to do is be disconnecting & re-connecting wires while doing tests. The more of that we do, the greater the likelihood of the re-connection process being wrong & creating a fault.

Unfortunately most of this stuff simply wasn\'t taught when I was an apprentice. And (from involvement with the Apprentice Challenge contest over several years) it\'s still obviously not being taught effectively.
The lads and lasses (presumably the cream of the crop)still turn up with test gear they don\'t know how to drive and little understanding of how to go about the testing process.

   

daniel2
Nov 06 2018 10:14

‘Unfortunately most of this stuff simply wasn\'t taught when I was an apprentice. And (from involvement with the Apprentice Challenge contest over several years) it\'s still obviously not being taught effectively.
The lads and lasses (presumably the cream of the crop)still turn up with test gear they don\'t know how to drive and little understanding of how to go about the testing process.’

Yes, it seems that testing is lacking particularly in domestic situations. Some sparkies I see barely have have any test equipment at all, simply relying on a Voltstick and waving it under a plug and saying ‘Yes it’s going and all good, off to the next job’.

I see on some videos on YouTube that in the UK the sparkies there are required to fill out verification inspection test sheets before any power is applied

   

pluto
Nov 06 2018 11:33

The testing shown in AS/NZS 3017 are least 20 years old and where originally devised by electrical inspectors employed by the Sydney City Council Power Supply Authority and specifically designed so that DEAD testing was the ONLY permitted way (and this was a long time before the prserent health and safety requirments came along).

The only exception being useing a voltage tester (Voltmeter) being permitted for some polarity testing as a secondary means only, the dead testing needed to prove the correct connections BEFORE any supply was connected.

In domestic installations, it was seaid to me many years ago, it was expected that the supply connection would NOT be made until the Power Supply Authority eelctrical inspector had signed off the whole electrical installation as being correct.

I meet some of these old Australian electrical inspectors when I first joined the EL-001 committee in 1997.

Earth fault loop testing and RCD testing was added later when it was revised to become AS/NZS 3017.

It is my personal view that some UK based testing methods adopt a position more related to NZ conditions, but if the testing of ring circuits is being explained this testing can be ingorned as this systerm of wiring in NOT used in AU or NZ. The other warning is the MEN system of earthing is NOT used in the UK so comments given about some earth testing of UK installations can also be ingored.

use Google to find suitable video clips.
   

dbuckley
Nov 06 2018 22:38

Pluto notes:

> The other warning is the MEN system of earthing is NOT used in the UK

I think you\'ll find it is used there, the UK has a TN-C-S variant that is almost identical to ours. The difference is that here the utility hands the electrician red(s) and a black, and the provision of the N/E bond and thus the creation of \"earth\" is the responsibility of the commissioning electrician. In the UK with TN-C-S the utility hands the electrician the earth as well, the N/E bond being in the \"cutout\", which is prior to the meter and is where the main fuse is housed, see picture.

https://i.imgur.com/RhdDxtF.jpg

The system even has a common name that shares two letters with ours: PME, the odd one out being \"protective\".

The UK has not used PME in installations as standard practice forever, and I\'ve seen installations from around the sixties that have a permanently attached label that indicates that the installation was using PME with the authority of the Secretary of State, so at one time it was clearly not the norm.

They have other earthing systems in common use, TT with earth rods and RCDs, and TN-S which has the metallic sheath of the supply cable as the earth all the way back to the substation, many older installations are like that.

   

AlecK
Nov 07 2018 09:23

The testing prescribed by \"3000\", and the test methods described in \"3017\" are almost entirely based on the supply being the \"MEN\" variant of TN-C-S.; and on fault protection being by automatic disconnection of supply.

Where other supply systems, and / or other methods of fault protection, are used; the tests required to demonstrate safety & compliance will vary.

\"3017\" is about to be reviewed, so any suggestions for improvement should be submitted to SNZ so they can be considered for inclusion.

\"3019\" (periodic verification) is also about to be reviewed, so suggestions for that should also be submitted.

Better to be in at the beginning than trying to change things in the few weeks of the \"public comment\" period.