Testing and Inspecting

[lofty84]

I have my 2230 testing and inspecting practical tommorow and I just wondered if anyone can tell me if Im doing things right or wrong.

The first test we will have to do is the continuity on protective conductors

For this I will select the low ohm reading on the test instrument and null the leads. Then I will take out the main bonding conductor from the main earthing bar in the consumer unit and applly a crocidile clipped lead to the end of it then with the other lead I will take it to the main bonding clamp and take a reading and then to the pipe work and take a reading. I would then record the highest value.

Is that correct please

sorry forgot to add that i will be expecting a reading of 0.05 ohms or less

 

[telectrix]

sounds right to me. but don't forget to null the leads with the wander lead connected ( if you are using a wander lead that is )

 

[Electricalserv]

Your meter and sequence is correct. All you want for R2 is end to end reading of that bonding conductor!

BTW* Inspection & Testing, We inspect before we test!!

 

[lofty84]

next I will need to check the continuity of the CPS, useing a choice of either method 1 (R1+R2) or method 2 (longlead)


method 1

for this I will need to make sure the leads are nulled and create a temporary link between the earth bar in the consumer unit and the line for each circuit I wish to test, I then make my way along the circuit testing between line and earth terminals at each point in the circuit recording the reading from the furthest point I think ? earth probe on first and then line.
although there is not a requirment for the R1 - Rn measurement I will repeat this but create a tempoary link beteen the earth bar and the neautral conductor for the circuit I wish to test and then test between the n and earth terminal at each point makeing a note of the reading gained at the furthest poin on the ciruit.

method 2

measures R2 (earth conductor) if they ask me to use this method instead of method 1 I would connect a long lead to the earth bar in the consumer unit and then with the other lead connect it to the earth terminal at the circuits furthest point.

I think .......

 

[lofty84]

Your meter and sequence is correct. All you want for R2 is end to end reading of that bonding conductor!

BTW* Inspection & Testing, We inspect before we test!!

thats a very good point

 

[Electricalserv]

next I will need to check the continuity of the CPS, useing a choice of either method 1 (R1+R2) or method 2 (longlead)


method 1

for this I will need to make sure the leads are nulled and create a temporary link between the earth bar in the consumer unit and the line for each circuit I wish to test, I then make my way along the circuit testing between line and earth terminals at each point in the circuit recording the reading from the furthest point I think ? earth probe on first and then line.
although there is not a requirment for the R1 - Rn measurement I will repeat this but create a tempoary link beteen the earth bar and the neautral conductor for the circuit I wish to test and then test between the n and earth terminal at each point makeing a note of the reading gained at the furthest poin on the ciruit.

method 2

measures R2 (earth conductor) if they ask me to use this method instead of method 1 I would connect a long lead to the earth bar in the consumer unit and then with the other lead connect it to the earth terminal at the circuits furthest point.

I think .......

Gn3 has it all in mate

 

[telectrix]

next I will need to check the continuity of the CPS, useing a choice of either method 1 (R1+R2) or method 2 (longlead)


method 1

for this I will need to make sure the leads are nulled and create a temporary link between the earth bar in the consumer unit and the line for each circuit I wish to test, I then make my way along the circuit testing between line and earth terminals at each point in the circuit recording the reading from the furthest point I think ? earth probe on first and then line.
although there is not a requirment for the R1 - Rn measurement I will repeat this but create a tempoary link beteen the earth bar and the neautral conductor for the circuit I wish to test and then test between the n and earth terminal at each point makeing a note of the reading gained at the furthest poin on the ciruit.

method 2

measures R2 (earth conductor) if they ask me to use this method instead of method 1 I would connect a long lead to the earth bar in the consumer unit and then with the other lead connect it to the earth terminal at the circuits furthest point.

I think .......

your method 1 would also confirm correct polarity. also, if it's a ring final circuit, you would cross connect the L and E 's at the CU and expect the readings to be the same at each outlet, except if there's a spur off the ring. again, you record the highest reading.

 

[lofty84]

now haveing done the continuity of protective conductors and CPS ( i dont mean to sound stupid but I would take the R1+R2 reading for all the circuits on the board at the same time wouldnt I)


I will need to move on to continuity of ring final circuits I will need to test end to end on the following r1-r1, r2-r2 and rn-rn

to do this I use the low resitance ohm meter setting again and apply one crocidle clipped lead to the line going out to the ring and the other crocidile clipped lead to the line comeing back in (thats r1-r1)

I do the same again but this time on the neautral (rn-rn) and then finaly the cpc (r2-r2)

this will tell me if I have continuity on each conductor in the ring circuit

all values should be within 0.05 ohms of each other if the conductors are the smae size

next I have to connect the line and neautral conductors together so that the outgoing line in connected to the returning neautral and vice versa. I then take a socket adaptor and take reading between the line and neautral at each socket by putting the test probes into the holes on the socket adaptor. If i get a higher reading from one of these sockets it is going to be the spur.

I can then do the same again useign the earth (r2) instead of the rn

this test should also enable me to confirm polarity on the ring

 

[i=p/u]

and if you notice a continuos rise at outlets, theres something wrong.????

your method 1 would also confirm correct polarity. also, if it's a ring final circuit, you would cross connect the L and E 's at the CU and expect the readings to be the same at each outlet, except if there's a spur off the ring. again, you record the highest reading.

 

[telectrix]

think you've got it spot on.

rem. on T/E the cpc is smaller csa, so on 2.5/1.5 your R2 will be 1.67 x R1.

 

[Sparky Ninja]

Do not forget at the very first instance before you disconnect the Earthing conductor for the continuity of protective conductors, that it needs to be locked off, and proven to be isolated.

 

[Sparky Ninja]

next I will need to check the continuity of the CPS, useing a choice of either method 1 (R1+R2) or method 2 (longlead)


method 1

for this I will need to make sure the leads are nulled and create a temporary link between the earth bar in the consumer unit and the line for each circuit I wish to test, I then make my way along the circuit testing between line and earth terminals at each point in the circuit recording the reading from the furthest point I think ? earth probe on first and then line.
although there is not a requirment for the R1 - Rn measurement I will repeat this but create a tempoary link beteen the earth bar and the neautral conductor for the circuit I wish to test and then test between the n and earth terminal at each point makeing a note of the reading gained at the furthest poin on the ciruit.

method 2

measures R2 (earth conductor) if they ask me to use this method instead of method 1 I would connect a long lead to the earth bar in the consumer unit and then with the other lead connect it to the earth terminal at the circuits furthest point.

I think .......

With regard to R1&RN it's between Line and Neutral, not Neutral and Earth.
With regard to the method 2 test, be sure to null out any wonder lead they give you. Or measure it's resistance separately and deduct its value.

 

[lofty84]

right next up then will be the insulation resistance test.

haveing made sure any sensitive equiptment is dissconected I would select the 500 V dc option (do I remove the main earthing terminal as to get rid of any paralell paths ?)

I will need to attach one crocidile clipped lead to the line conductor and the other to neautral conductor and press test on the megger I should expect a reading of >299 M ohms on the tester I will be useing

next I test between the line conductor and the main ear bar in the consumer unit again expecting a reading of >299 M ohms and then finally between the neautral and main earth bar in the consumer unit again looking for a >299 M ohm reading.

if the reading is less then 2 M ohms i will need to investigate as to why this is although the regs state that the minimum allowable reading for insulation resistance is 1 M ohm

 

[telectrix]

sound advice there from the wookie. LOL.

 

[lofty84]

well spotted widdler