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Brilliant post. I've been trying to understand testing methods for five years. i understood the "simplicity" of carrying out testing after reading this thread once...
 
Great read guys, having been off the tools for a long time due to illness this thread has made things a lot simpler. Took my 236/2 in 1986 and only just passed my 17th last month, lots of hard work ahead for sure. Thanks again Chris
 
this about right?

1 Safe isolation
· Remove Cover
· Identify the point of isolation for the system or circuit. Lock off, place warning label and keep the key to the lock with yourself
· Select approved test equipment and ensure that it works correctly by testing on the proving unit.
· Test the outgoing side of the means of isolation (Main Switch, MCB, Fuse, etc.) to make sure it is dead.

Single Phase installations test to confirm that there is no voltage between:
- Line and Neutral
- Line and Earth
- Neutral and Earth.

· Re-test the test equipment on the proving unit

The following tests are carried out with the Consumers main switch isolated
2 Extenal earth fault loop impedance - ZE
3 Re-connect the Earthing conductor and measure your PFC
PSCC Prospective short circuit current measured between L & N

PEFC Prospective earth fault current measured between L & E

PFC Prospective fault current the highest reading from the 2 tests above
4) Check the main earthing conductors and main bonding conductors are continuous to Gas/Water
5) Continuity of protective and bonding conductors (R1 + R2)
Taken at furthest point
6) Continuity of ring final circuit conductors
· r1 rn r2
· cross connect L1,N2, take reading on L2 and N1, remember it, then join them
readings at each socket should be ¼ of above value.
· Repeat above with L1, E2 and L2, E1 (highest reading R1+?R2)
7) Insulation Resistance
Test at 500v dc neutral & line
Test at 500v dc line - cpc
Test at 500v dc neutral to cpc
Toggle switches on 2 way lighting
8) Polarity


Reason: To check that all accesories are correctly connected to line, neutral and earth and that all switches and circuit breakers are connected in the line conductor only.

Method: The method for this is the same as for continuity and is usually done at the same time by operating switches etc whilst conducting the test.
9) Earth electrode resistance
An earth fault loop impedance tester is connected between line and earth at the origin of the supply and a test performed. The result of which is considered the resistance of the electrode (Ra)

10) remove locks and tags
11) Live polarity test
one probe shall be placed on the incoming neutral, and the other on the incoming line conductor, on the main breaker. The indicator should show it is live. One probe shall now be placed on the CPC and the other on the incoming line conductor. The indicator should show it is live. A test shall be preformed between CPC & incoming neutral. The indicator should show that it is not live.
12) replace Cover
13) Earth fault loop impedance
An earth fault loop impedance tester is connected to line and earth at the furthest point on the circuit and the test performed.
Results compared against table 41, rule of thumb, x 0.8,
14) RCD test

15) Functional testing

Reason: To make sure all switches, isolators, MCB's etc. work as they should.

Method. Self explanatory.
 
Post resurrection! :egypt:

Mainly correct if briefly covered.
A couple of points in red/orange
4) Check the main earthing conductors and main bonding conductors are continuous to Gas/Water
5) Continuity of protective and bonding conductors (R1 + R2) This is not R1+R2 and is the same as 4.
This is the one
5) Continuity of radial circuits circuit protective conductors (R1+R2)
Maximum at furthest point

6) Continuity of ring final circuit conductors
· r1 rn r2
· cross connect L1,N2, and cross connect L2 and N1,
You can measure between them at this point this will give you the value you expect on all other sockets which should be equal to (r1+rn)/4
readings at each socket should be ¼ of r1+rn.
· Repeat above with L1, E2 and L2, E1 (highest reading recorded as R1+R2)
7) Insulation Resistance
Test at 500v dc neutral & line
Test at 500v dc line - cpc
Test at 500v dc neutral to cpc
Toggle switches on 2 way lighting and test again, not required for Neutral to cpc

remember all the tests for the RCD
Idn at 0.5, 1,
5 (if 30mA) at both +ve and -Ve half cycles
Test button works
 
Nothing wrong with a reserection, what was important to someone 5 years ago is important to me now :)
i have my niceic test in a few weeks so decided to make a quick guide.
Thanks for the corrections ,
ill update the master I made for myself now
 
Post resurrection! :egypt:

Mainly correct if briefly covered.
A couple of points in red/orange
4) Check the main earthing conductors and main bonding conductors are continuous to Gas/Water
5) Continuity of protective and bonding conductors (R1 + R2) This is not R1+R2 and is the same as 4.
This is the one
5) Continuity of radial circuits circuit protective conductors (R1+R2)
Maximum at furthest point

6) Continuity of ring final circuit conductors
· r1 rn r2
· cross connect L1,N2, and cross connect L2 and N1,
You can measure between them at this point this will give you the value you expect on all other sockets which should be equal to (r1+rn)/4
readings at each socket should be ¼ of r1+rn.
· Repeat above with L1, E2 and L2, E1 (highest reading recorded as R1+R2)
7) Insulation Resistance
Test at 500v dc neutral & line
Test at 500v dc line - cpc
Test at 500v dc neutral to cpc
Toggle switches on 2 way lighting and test again, not required for Neutral to cpc

remember all the tests for the RCD
Idn at 0.5, 1,
5 (if 30mA) at both +ve and -Ve half cycles
Test button works

Post resurrection! :egypt:

Mainly correct if briefly covered.
A couple of points in red/orange
4) Check the main earthing conductors and main bonding conductors are continuous to Gas/Water
5) Continuity of protective and bonding conductors (R1 + R2) This is not R1+R2 and is the same as 4.
This is the one
5) Continuity of radial circuits circuit protective conductors (R1+R2)
Maximum at furthest point

6) Continuity of ring final circuit conductors
· r1 rn r2
· cross connect L1,N2, and cross connect L2 and N1,
You can measure between them at this point this will give you the value you expect on all other sockets which should be equal to (r1+rn)/4
readings at each socket should be ¼ of r1+rn.
· Repeat above with L1, E2 and L2, E1 (highest reading recorded as R1+R2)
7) Insulation Resistance
Test at 500v dc neutral & line
Test at 500v dc line - cpc
Test at 500v dc neutral to cpc
Toggle switches on 2 way lighting and test again, not required for Neutral to cpc

remember all the tests for the RCD
Idn at 0.5, 1,
5 (if 30mA) at both +ve and -Ve half cycles
Test button works

Use correct terminology not Main Earthing Conductor , it is the Earthing Conductor
Toggle Switch 2 way lighting in the on/off position.

Continuity of Final Circuits use method 1 between Line & CPC at the Consumer Unit
Method 2 for R2 value only, or Bonding Conductors- use long lead and disconnect one end of the conductor to avoid paths.
( Verify values by reference to tables of resistance values)

Stage 1
Ring Final Circuits measure end to end resistance of little r1=line. Little rn= neutral and little r2 = cpc
r1 = r2 depends on the size of the cpc (for 2.5mm/1.5mm T&E, r2 =1.67 r2)

Stage 2 X - connect line & neutral of opposite legs. Measure at each outlet between L & N. Value r1/2 for sockets on a ring. (or r1 + rn/4)
Any higher values should be investigated as they (may) indicate spurs

Stage 3 X - connect line & CPC of opposite legs. Measure at each outlet between line & CP. Value (r1 + r2/4)
for sockets on the ring final circuit
Spurs will read higher than sockets on the ring final circuit
Record the highest measured value as your ( R1 + R2)

Insulation Resistance
(Test 1 Live-Live) and between Live & CPC connected to the earthing arrangements (Test 2: Live-Earth).
Remember
Precautions and Preconditions when doing this test

SELV & PELV, 250V d.c. Minimum acceptable = 0.5M Ohm
Circuits up to 500V nominal, 500V d.c. Minimum = 1M Ohm
(surge protective devices: test at 250V d.c. Minimum)
Where equipment cannot be disconnected it is acceptable to measure between live conductors (connected together) and earth only.
 
Thanks for that , sorry my bad , I did it as more of a brief for me so shouldn't have
really posted it , but thanks for filling in the extras.
I'll update my master too so I have correct terminology

regards
lee76
 
Its an easy to follow and understand schedule of tests, its contains all the information I've been reading in the 17th EIT Testing Guides but clearer. Now I've got my own multitester I think I'll practice on my own house next week and do a full periodic inspection and Test. I find it hard to believe that having been an Electrician for 40 years I'm not actually qualified to do this professionally :-( Think I'll have to sign up for some courses LOL
 
You dont need a qualification to carry out inspection & testing, when serving your apprenticeship you will have learned how to carry out an innitial verification of a new installation at least. Periodic inspections (EICR) possibly not but none the less no qualification as such is required, just competence and a sound knowledge of the installation that is having a report carried out on is necessarry.

Although some CPS schemes may ask for them these days. All that said, holding the 2394/5 is certainly worthwhile IMO.
 
Last edited:
a CPS scheme will still require 17th edition, silly really
my partner and myself joined elecsa, even though he had 2394
and 2395 it was irrelevant , as we both had 17th edition
either of us could have done the assessment, and strangely enough I did it.
I taught myself from books
 
Sorry should have quoted below.

I ll tell you what I'm doing, I am installing new circuits and breaking into exsisting rings ,when I install a new circuit I issue a New installation cert and when I tamper with a ring I issue a Minor works cert,but the thing is I am doing this in a very large store and the power can not be turned off so I can not do my Ze so I think I put this down as a limatation and just do PFC or if I can get my hands on previous test sheets issued can I use them?



Reply


Previous test sheets should be used to determine if there is any deterioration from the last test it is also helpful if locating circuits and additional work that has been carried out.
You should not use readings from previous tests on a new EICR as the values may have worsened.
LIM it is the correct action but must be agreed with person ordering the work and provide reasons on EICR. If they are unhappy to have it LIMed then they must arrange for a time to do the test. Probably will be happy to LIM if not charge out of hours rate min of 8 hours. Not you fault coustomer will not let you isolate store.
All other points you mention are spot on.
 
Is this all still applicable Sintra - I assume it is, just asking. This thread hasn't been replied to since 2019. And that either means it's really well discussed and there's nowt to add to it. Or there's a change somewhere in the industry and it isn't applicable.

I doubt that's the case.

Just checking though. :D

Lemme know either way matey.
 
I can't see the theory changing beyond what has been detailed prior.

Only tweak I would make it to include calculations to be done at relevent points. Anyone can press a button but it takes an electrician to know how to interpret the results - Knowing what you expect to see before you press that button and from that; making the call as to whether or not the reading is acceptable is that mark of a switched on (excuse the pun) spark, compared to a dull one.
 
A multi meter should not be used for safe isolation as it may be set in various positions.
For example you start of with it on the ac voltage setting but in the middle of the procedure you inadvertently move the selector to a different range which could prove fatal.

The reason the proper test equipment to GS38 should be used is to remove the possibility of human error.
I would include pen type voltage indicators and neon screwdrivers also as unsuitable for safe isolation.
 
Safe isolation

The procedure for proving dead should be by use of a test lamp or two pole voltage detector as recommended in HSE Guidance Note GS38.
Non-contact voltage indicators (voltage sticks) and multi-meters should not be used. The test instrument should be proved to be working on a known live source or proprietary proving unit before and after use. All phases of the supply and the neutral should be tested and proved dead.


Test sequence and descriptions

The following tests are carried out with the Consumers main switch isolated

1. Extenal earth fault loop impedance
Reason: To establish that a good earth exists at the installation in order for the remaining tests to go ahead.

Method: Disconnect the main earthing conductor from the main earthing terminal. An earth fault loop impedance tester is connected at line and earth (main earthing conductor) at the supply side of the installation and a test performed. Reconnect the main earthing conductor. The result is Ze and recorded on the sheet. The prospective fault current is measured at the same time after the reconnection of the main earthing conductor.


2. Continuity of protective and bonding conductors
Reason: To check that all circuit protective conductors (green and yellow cables) are continuous and are present at every electrical accessory on the circuit. Also to check that the main earthing conductor and main bonding conductors are continuous and correctly connected.

Method 1: The line conductor is connected to the circuit protective conductor of the same circuit at the consumer unit and a measurement taken at ALL accesories on that circuit between line and c.p.c. The highest measurement obtained is recorded on the test report.
Test result is R1 + R2. The line conductor and neutral conductor are then connected and the above repeated to obtain R1 + Rn

Method 2 (used for main earth and main bonding conductors): A wandering lead is connected to one end of the conductor to be tested and a measurement taken between the other end of this lead and the other end of the conductor.
Test result is R2.
During this test polarity can be checked as well. The continuity of the neutral conductor can also be checked.


3. Continuity of ring final circuit conductors
Reason: This test ensures that all ring final circuits (sockets usually) are indeed a continuous ring with no interconnects or breaks within it.

Method: The line, neutral and earth conductors of the circuit are identified and a measurement from one end to the other end of each is taken. These results are r1, r2 and rn.
The incoming line conductor is then connected to the outgoing earth conductor and the outgoing line conductor is connected to the incoming earth conductor. A measurement is then taken at ALL socket outlets on the ring. The highest of which is recorded on the report.
This result is R1+R2 for that circuit. The above is then repeated using the neutral conductor instead of the earth conductor. This test provides R1+Rn which does not need to be recorded on the report but is essential to check the circuit correctly.


4. Insulation Resisitance
Reason: This test checks whether the insulation around a cable is still intact and has not broken down over time. It is a good indicator of the age of an installation.

Method: An insulation resistance tester is connected across line and neutral tails at the origin of the supply. 500V are then pumped down the conductors to see if any voltage leaks across from one conductor to the other. The same is then done for the line and earth and the earth and neutral conductors.


5. Polarity
Reason: To check that all accesories are correctly connected to line, neutral and earth and that all switches and circuit breakers are connected in the line conductor only.

Method: The method for this is the same as for continuity and is usually done at the same time by operating switches etc whilst conducting the test.


6. Earth electrode resistance
Reason: To make sure that any earth electrode used is of a sufficiently low impedance to allow the timely operation of the RCD protecting the installation.

Method: An earth fault loop impedance tester is connected between line and earth at the origin of the supply and a test performed. The result of which is considered the resistance of the electrode (Ra).


The following tests are carried out with the Consumers main switch energised


7. Live polarity test
Reason: To verify polarity of supply authorities system.

Method: An approved voltage indicator shall be used or test lamp to GS38. Using the approved voltage indicator, one probe shall be placed on the incoming neutral, and the other on the incoming line conductor, on the main breaker. The indicator should show it is live. One probe shall now be placed on the CPC and the other on the incoming line conductor. The indicator should show it is live. A test shall be preformed between CPC & incoming neutral. The indicator should show that it is not live.


8. Earth fault loop impedance
Reason: This test is done at the furthest point on a circuit in order to make sure the impedance of the earth path is not too high even at the furthest point so that sufficient current will flow under fault conditions to take out the circuit breaker protecting the circuit.

Method: An earth fault loop impedance tester is connected to line and earth at the furthest point on the circuit and the test performed.


9. RCD test
Reason: To make sure RCD's trip within the correct time

Method: An RCD tester is connected and a test at 1/2 times, 1 times and 5 times the trip current is performed on each side of the cycle and a time of trip obtained. Usually milli-seconds with the highest being recorded. The manual test button is then pressed.


10. Functional testing
Reason: To make sure all switches, isolators, MCB's etc. work as they should.


Method. Self explanatory.
A very in depth post. Yes we who are longer in the trade tend to complacency
I found the test meathods covered all the basic tests, except erroneous testing.
Heads up Sintra
RMS
 
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