Testing and Verification of Electrical Installations

17larsson

Take a loop reading at the board and subtract that from your loop readings at your outlets

liveandnetural

a question aimed at the industrialist among us

in terms of recording test value reading onto (test record sheets) have any seen any beter system than the standared test record sheet aviable from either of the two saftey bodies
i have seen some of the larger contractor groups using xl templates to create a simplfied record sheets just woundering has anyone seen or used a software based one or a system for industrial use for recording machine Installation setup and ongoing modifications?

all inputs welcome

Casey78

Hi.
Would anyone have on file an editable copy of a test record sheet for PIRs?
I've been trying to make one up on MS WORD but just can't get it right..

I have recently got a contract Periodic Testing for a business chain so rather than filling them out by hand as I was doing I wanted to fill them out on the laptop as I test.
I don't want to be scanning them onto the PC either.
As I said I have tried unsuccessfully to throw something together on word.
I'm just not that good with it.
Any help would be great thanks.

Hoagy

Casey78 wrote: »

Hi.
Would anyone have on file an editable copy of a test record sheet for PIRs?
I've been trying to make one up on MS WORD but just can't get it right..

I have recently got a contract Periodic Testing for a business chain so rather than filling them out by hand as I was doing I wanted to fill them out on the laptop as I test.
I don't want to be scanning them onto the PC either.
As I said I have tried unsuccessfully to throw something together on word.
I'm just not that good with it.
Any help would be great thanks.

Try Excel, it's much more suitable for test records.

crasy dash

Just curious lads what testers are electricians using for testing these days.

Have a friend who is after getting a job installing pre pay meters.

Part of the contract he got, is he has to have his own test gear.

I have used robin kewtech personally.

I'm sure megger fluke etc have multifunction meters.

Let me know what meter you use and any faults you have with them.

Gashmuncher

Just to stir this one up again, it is my opinion that the vast majority of electricians, even those who are deemed to be QCs (Qualified Certifiers) simply do not know how to correctly test an electrical installation as per part 6 of the wiring rules. Most electricians do not even understand what the objectives of each of the required test are. It is critical that electricians actually understand the fault they are looking, and in my opinion most don't. Attempting to test an installation by following a series of steps which are listed in a book is a recipe for disaster. What is required is an understanding of what can go wrong and an understanding of what each test is actually telling you. The tests are designed to highlight the normal mistakes which electricians can and do make which are easily overlooked and can leave an installation in a dangerous condition.

See below for overview of the required tests and the actual fault you are looking for.
Test 1,2,3,&4 are pre connection tests and are done with the installation dead. Gets 5&6 are post connection tests and can only be done after power is switched on.

TEST 1
Continuity of protective and bonding conductors.
This test is simply to confirm that all earth conductors are "electrically sound and correctly connected" This is done by simply measuring the resistance of the earth cables. A low reading (generally less than .5 ohm,) indicates a good earth. There are a number of ways to do this test but the simplest is a wander lead. The test needs to be done with a proper "low ohm meter" which can accurately measure very low values of resistance. A multimeter will not measure low ohm values (less than10 ohms) accurately. The thing to note here is that unlike a disconnection of the live or neutral, the circuit will work normally if no protective conductor is present. If the earth is inadvertently left disconnected everything will seem to be normal but in the event of an earth fault there are no protective measures in place.

TEST 2
Continuity of ring main circuits. Another simple low ohms test test to confirm that both legs of live ,neutral and earth are correct in a ring main circuit. Again note that if an open ring on any conductor exists this is not easily detected as the circuit will appear to work normally. At the same time, particularly if the ring is protected by a 32amp MCB a very dangerous situation can arise if the ring is open. The test is simple. Measure the resistance between the two lives , neutrals and earths. Rembering that 100 meters of 2.5 cable measures 0.7 ohms it is fairly obvious that we will normally expect to get reading less than an ohm and and as all conductors are the same length and the same cable size the lives and neutrals should match. In the case of twin and earth cable the earth is a smaller cable and therefore should have a higher resistance.

TEST 3
Insulation Resistance, this test seems to be little understood by most electricians. The whole point of the test is to ensure that all live and neutral conductors are separated electrically from the earth conductors by a minimum of 1 mega ohm. Unlike the first two tests we are looking for a very high reading. It is important to understand that 1 mega ohm is a high reading. Most electricians do not seem to know that 1 mega ohm is one million ohms. (1,000,000) 1 million of anything is a lot, and 1 mega ohm is a lot of resistance. Readings in the order of 10 mega ohms ar perfectly acceptable and normal. It is a requirement that the test is carried out at 500 volts. The simple way to ensure that this voltage does not damage any electronic equipment is to short the live and neutral conductors together and the test between the shorted live and neutral to earth. This ensures that there is no actual voltage across the live and neutral and therefore no potential to damage equipment. Any reading over 1 mega ohm is a pass. It is impossible to obtain readings of greater than 200 or greater than 500 or greater than 999 mega ohm all the time. The most common insulation resistance fault found is a short between neutral and earth.

TEST 4
Erroneous connections between circuits. This simple test is to ensure that the lives from different circuits are not inadvertently connected together. Erroneous means in "error" . The test is to ensure that circuits are not connected together in error. Again the problem with this fault is that everything will work and seen to be normal. But it is possible that two separate MCBs can be feeding the same circuit. The test is in effect a continuity test to ensure that with all other MCBs on, each circuit disconnects from the live.

TEST 5
Live to earth loop impedance.

TEST 6
RCD trip times

2011

Gashmuncher wrote: »

Just to stir this one up again, it is my opinion that the vast majority of electricians, even those who are deemed to be QCs (Qualified Certifiers) simply do not know how to correctly test an electrical installation as per part 6 of the wiring rules.

I agree, that is why I started this sticky.

It is critical that electricians actually understand the fault they are looking, and in my opinion most don't.

Many electricians can never carry out any testing, nor are they expected to. Large electrical contractors will have a dedicated testing team. This is a shame, because knowing how to test is another string to your bow and makes you far more employable.

TEST 1
Continuity of protective and bonding conductors.
This test is simply to confirm that all earth conductors are "electrically sound and correctly connected" This is done by simply measuring the resistance of the earth cables.

I generally split this test into two as they have different aims:

1) Bonding conductors:

This is a case of measuring the resistance between extraneous conductive parts that are simultaneously accessible. For example measuring the resistance between the outer casing of a motor and a pipe that is close to the motor. If the resistance is low then in the event that the casing becoming live the potential difference between it and the pipework (or touch voltage) will be minimal. A wander lead is generally not required for this as conductive parts are generally close enough ti each other for the test instrument leads to reach.This is not always achieved by using cables. For example when wiring a milking parlour in the distance past I had all of the feeding troughs for the cattle welded together so that the became one unit. This ensured that they were all at a common potential. I know that cables linking the troughs were unlikely to last in this environment.

2) Continuity of protective conductor:

A low reading (generally less than .5 ohm,) indicates a good earth.

This applies to the CPC (Circuit Protective Conductor). "A good earth" is not the aim of "equipotential bonding" although it is generally a consequence of it. The aim of equipotential bonding is to keep simultaneously conductive parts at the same potential by connecting them to each other, whereas the aim of the CPC is to ensure that in the event of an earth fault the disconnection times for the associated protective device(s) are met by providing a low resistance path to earth. Remember a low resistance to earth permits a large earth fault current to flow which means that the protective device to operates quicker.

TEST 2
Continuity of ring main circuits. Another simple low ohms test test to confirm that both legs of live ,neutral and earth are correct in a ring main circuit. Again note that if an open ring on any conductor exists this is not easily detected as the circuit will appear to work normally. At the same time, particularly if the ring is protected by a 32amp MCB a very dangerous situation can arise if the ring is open. The test is simple. Measure the resistance between the two lives , neutrals and earths.

... so generally the tester will disconnect the lives and the neutrals at the distribution board to carry out this test.

TEST 3
Insulation Resistance, this test seems to be little understood by most electricians. The whole point of the test is to ensure that all live and neutral conductors are separated electrically from the earth conductors by a minimum of 1 mega ohm.

...and to ensure the integrity of resistance between phase and earth and phase and neutral. Additionally in three phase installations the the resistance between phases is very important

Unlike the first two tests we are looking for a very high reading. It is important to understand that 1 mega ohm is a high reading. Most electricians do not seem to know that 1 mega ohm is one million ohms. (1,000,000) 1 million of anything is a lot, and 1 mega ohm is a lot of resistance.

In industrial installations we generally test at 1kVDC and would not be satisfied with a 1 MΩ result. Insulation resistance testing is not carried out this way in ATEX areas as the risk of a spark is considered more of a hazard that an issue with the insulation resistance. Instead a suitable multimeter is used.

TEST 4
Erroneous connections between circuits.

I find that there errors as well as most others are generally found during the "visual inspection" which is why I think it is the single most important test. During this part of the test most issues (such as reverse polarity, damaged conductors / apparatus, poor installation) are detected.

TEST 5
Live to earth loop impedance.

Refer to table A61C in ET101:2008 (for max. disconnection times 0.4 s)

TEST 6
RCD trip times

See Annex 61G in ET101:2008

Gashmuncher

Fully agree with all above. The actual Insulation Resistence (IR) limit required in the rules for explosive atmospheres is 10meg ohm and Normal installations is 1 meg ohm. While I agree that it is normal to look for values in excess of these limits it is also important to understand that an IR reading over the mimium required, fully complies with part 613.3 of ET 101 the wiring rules. I came across an situation where an electrician replaced 200 meters of 5 by 50 Square cable because the mimium IR was 375 meg ohm.

Tdude

Hi,I'm just wondering how to test for max earth fault loop impedance at a light when there is no Earth at the fitting?Thanks for any feedback!

brightspark

Why is there no Earth at the fitting?

Risteard81

If there is no cpc then there obviously is no earth fault loop and therefore the impedance of same cannot be tested.

Tdude

brightspark wrote: »

Why is there no Earth at the fitting?

It's an old property

Tdude

Risteard81 wrote: »

If there is no cpc then there obviously is no earth fault loop and therefore the impedance of same cannot be tested.

Thanks for reply,so for the test record sheet results is it n/a?fittings are class II so they don't require a new Earth to be pulled in

2011

Tdude wrote: »

Thanks for reply,so for the test record sheet results is it n/a?fittings are class II so they don't require a new Earth to be pulled in

There should be an earth available even if it is not required for that particular light so that it can be connected should the light be changed for a different type in the future.

I would not write "N/A" as this suggests that an earth is not required when the regulations state otherwise.

brightspark

Aren't you, in instances such as this, supposed to highlight that the installation does not meet current guidelines on the report?

Risteard81

I'm not sure whether we are discussing a PIR here or otherwise.
If it is a PIR (Periodic Inspection Report) then I would record "N/A" but I would also be making a coded observation relating to the lack of the cpc at each point in the wiring. If it is installation work then you need to ensure that the existing installation is adequate to support your additions/alterations.

ptogher14

I don't mean to sound like a smart arse but if you have to ask that question you obviously don't have a full understanding of what you're doing. It might be no harm to get someone to go through testing with you.

Stoner

report noted, i dont see any indication that the op can't test, they just want to know what to write into the cert in this instance, I dont see why the op cant ask this question here

2011

I think that electricians should always be encouraged to ask questions rather than pretend to have all of the answers. There is far to much of this going on in my opinion.

brightspark

2011 wrote: »

I think that electricians should always be encouraged to ask questions rather than pretend to have all of the answers. There is far to much of this going on in my opinion.

I did my senior trades in 1989, with just the odd few courses since then. I sometimes wonder what I've forgotten, always interesting to see questions here and rediscover lost knowledge that I hadn't had cause to use since my apprenticeship or even learn something new.

I'd have very little tolerance for an electrician not knowing the basics but not all questions are straight forward and many of us occasionally find ourselves suddenly faced with a situation we barely covered in a theory class many years previously.

The electrical trade is extremely varied with some doing just house wiring and others working on complex industrial equipment, but due to jobs changing we often have to move into areas where there may be some holes in our knowledge. (During interviews is usually when I find dusty brain cells struggling to remember which formula applies etc.)

Would anyone else be interested in a thread where we challenge each other to answer questions on obscure and maybe some less obscure areas of our trade?

Tuco88

+1

2011 wrote: »

I think that electricians should always be encouraged to ask questions rather than pretend to have all of the answers. There is far to much of this going on in my opinion.

The electrical industry is so vast now it's extremely difficult to know all,and it's a continuous learning experience it's why I like it. And then forgetting I hate that the most.

Had an issue before with EFLI testing 3phase outlets with no neutral, not a problem with sone testing equipment, not so with a particular fluke model.

youtube!

Slightly off topic perhaps but as i have only recently returned to Electrical work(as an employee) I have noticed just how much longer it now takes to complete a consumer unit , I cannot find the actual regulation but is it now absolutely necessary for every cable to be identified individually and every earth and neutral to correspond in the correct order on their respective terminals? I have been doing this but it takes half a day now to do something which used to take a couple of hours. I can see the huge advantage in a fault finding situation but I would like to know if all this extra identification is an absolute regulation or simply a best practice suggestion. I have to also point out it that as each cable is now terminated with the outer PVC still at the board ( to show which circuit it is) it makes for a very untidy looking job, there is simply no way of making it look neat if you cannot strip back the entire cable.

mark085

Gashmuncher wrote: »

Just to stir this one up again, it is my opinion that the vast majority of electricians, even those who are deemed to be QCs (Qualified Certifiers) simply do not know how to correctly test an electrical installation as per part 6 of the wiring rules. Most electricians do not even understand what the objectives of each of the required test are. It is critical that electricians actually understand the fault they are looking, and in my opinion most don't. Attempting to test an installation by following a series of steps which are listed in a book is a recipe for disaster. What is required is an understanding of what can go wrong and an understanding of what each test is actually telling you. The tests are designed to highlight the normal mistakes which electricians can and do make which are easily overlooked and can leave an installation in a dangerous condition.

See below for overview of the required tests and the actual fault you are looking for.
Test 1,2,3,&4 are pre connection tests and are done with the installation dead. Gets 5&6 are post connection tests and can only be done after power is switched on.

TEST 1
Continuity of protective and bonding conductors.
This test is simply to confirm that all earth conductors are "electrically sound and correctly connected" This is done by simply measuring the resistance of the earth cables. A low reading (generally less than .5 ohm,) indicates a good earth. There are a number of ways to do this test but the simplest is a wander lead. The test needs to be done with a proper "low ohm meter" which can accurately measure very low values of resistance. A multimeter will not measure low ohm values (less than10 ohms) accurately. The thing to note here is that unlike a disconnection of the live or neutral, the circuit will work normally if no protective conductor is present. If the earth is inadvertently left disconnected everything will seem to be normal but in the event of an earth fault there are no protective measures in place.

TEST 2
Continuity of ring main circuits. Another simple low ohms test test to confirm that both legs of live ,neutral and earth are correct in a ring main circuit. Again note that if an open ring on any conductor exists this is not easily detected as the circuit will appear to work normally. At the same time, particularly if the ring is protected by a 32amp MCB a very dangerous situation can arise if the ring is open. The test is simple. Measure the resistance between the two lives , neutrals and earths. Rembering that 100 meters of 2.5 cable measures 0.7 ohms it is fairly obvious that we will normally expect to get reading less than an ohm and and as all conductors are the same length and the same cable size the lives and neutrals should match. In the case of twin and earth cable the earth is a smaller cable and therefore should have a higher resistance.

TEST 3
Insulation Resistance, this test seems to be little understood by most electricians. The whole point of the test is to ensure that all live and neutral conductors are separated electrically from the earth conductors by a minimum of 1 mega ohm. Unlike the first two tests we are looking for a very high reading. It is important to understand that 1 mega ohm is a high reading. Most electricians do not seem to know that 1 mega ohm is one million ohms. (1,000,000) 1 million of anything is a lot, and 1 mega ohm is a lot of resistance. Readings in the order of 10 mega ohms ar perfectly acceptable and normal. It is a requirement that the test is carried out at 500 volts. The simple way to ensure that this voltage does not damage any electronic equipment is to short the live and neutral conductors together and the test between the shorted live and neutral to earth. This ensures that there is no actual voltage across the live and neutral and therefore no potential to damage equipment. Any reading over 1 mega ohm is a pass. It is impossible to obtain readings of greater than 200 or greater than 500 or greater than 999 mega ohm all the time. The most common insulation resistance fault found is a short between neutral and earth.

TEST 4
Erroneous connections between circuits. This simple test is to ensure that the lives from different circuits are not inadvertently connected together. Erroneous means in "error" . The test is to ensure that circuits are not connected together in error. Again the problem with this fault is that everything will work and seen to be normal. But it is possible that two separate MCBs can be feeding the same circuit. The test is in effect a continuity test to ensure that with all other MCBs on, each circuit disconnects from the live.

TEST 5
Live to earth loop impedance.

TEST 6
RCD trip times

Thanks for the info gash muncher I started the course today it was a lot to take in on first day I hope I can get the pass not feeling to confident though tbh

2011

mark085 wrote: »

Thanks for the info gash muncher I started the course today it was a lot to take in on first day I hope I can get the pass not feeling to confident though tbh

This is an area that many electricians struggle with. Post any questions here, there are a number of posters that are strong in this area.

dingding

I see where a property has been disconnected from the supply, tests/certification are required before the ESB Networks "re-energize" the property.

Can anyone let me know what is involved in the test? Would I just approach an electrical contractor to carry out the work.

Also is there any new regulations over the years that would lead to a premises not being in compliant.

P.S. Trained as an electrician in the early eighties but have not been in the industry or on the tools for over 20 years.

Dubsparkie

Hi guys, just quick question maybe obvious to some here but I'm unsure. If I am installing an EV car charger or PV panels in a domestic situation do I need to test and verify the existing install before and after the additional works. The charge point/ PV setup and associated cabling, rcbo, isolators etc being the only works carried out by myself i.e I would not be upgrading or making any changes to the existing board.

meercat

Dubsparkie wrote: »

Hi guys, just quick question maybe obvious to some here but I'm unsure. If I am installing an EV car charger or PV panels in a domestic situation do I need to test and verify the existing install before and after the additional works. The charge point/ PV setup and associated cabling, rcbo, isolators etc being the only works carried out by myself i.e I would not be upgrading or making any changes to the existing board.

Welcome to boards

You have to do a pre assessment to make sure existing mains and earthing arrangements are suitable. You cannot carry out any works if they’re not.

You have test and certify only the work you carry out

Only a rec can carry out this work

Dubsparkie

meercat wrote: »

Welcome to boards

You have to do a pre assessment to make sure existing mains and earthing arrangements are suitable. You cannot carry out any works if they’re not.

You have test and certify only the work you carry out

Only a rec can carry out this work

Thanks for that. I have been off the tools for some years and recently got the new company I work with certified and completed all the relevant courses etc I just wasn't sure on that particular section. There is so many companies now adding renewable and charging to their structure but there was not a lot of information on the exact requirement around pre and post install.