Testing lighting

[smity]

Hi guys

ive not done any real testing on commercial jobs other than fault finding etc and was wondering, when dead testing lighting circuits would r1+r2 be accurate as the r2 will most probably not run the exact same route as the r1 with more connections etc so would you do an r2 flying lead method?

Thanks

 

[vernam616]

Testing is testing really and circuits are circuits, just on a bigger scale.

Take a r1+r2 at every point, and dont forget to null your leads

You should look at completing a 2394/2395 course

 

[smity]

So not just at the furthest point?

I sat my 2391 but failed the theory unfortunately and never got round to doing it again but will be doing the new course when I get time.

 

[vernam616]

Well if you have not installed and are carrying out a periodic, you wont know which is the last connection or struggle to find the last connection, by testing every point you can record the highest reading you take and should clarify the end of the circuit

 

[smity]

Ah yes, I was thinking more along the lines of a new installation where the good sparks have marked on the drawing the EOL thanks

 

[davesparks]

It's not just about getting a number to write in a box, the whole point is to prove the continuity of the cpc throughout the whole circuit. How many points do you think you need to test at to safely say that the cpc is present and correct at every point?

 

[smity]

It's not just about getting a number to write in a box, the whole point is to prove the continuity of the cpc throughout the whole circuit. How many points do you think you need to test at to safely say that the cpc is present and correct at every point?

I fully understand the reason for testing the CPC and that we don't just test to fill numbers into box's, depending on how it's wired the EOL would prove its present at every point unless there are stabs off.

my question was more along the line of when using twin you know that the r2 is exactly the same length as the r1 but using singles they may differ so would you get a true reading?

cheers

 

[PEG]

I fully understand the reason for testing the CPC and that we don't just test to fill numbers into box's, depending on how it's wired the EOL would prove its present at every point unless there are stabs off.

my question was more along the line of when using twin you know that the r2 is exactly the same length as the r1 but using singles they may differ so would you get a true reading?

cheers

Hi,i am guessing you mean t&e?...if so,sometimes you will get readings which may indicate,through calculation,that the circuits are the same length,but this will not be so. Remember,you are just looking at on Ohms reading,and resistance can be made up of more than just the conductors impedance...:stooge_curly: This is why effective testing is achieved by more than just meter readings.

 

[Richard Burns]

The reading you want to obtain is the resistance of the line and cpc in total, whether they are the same length or not is immaterial you will still need the resistance of that part of the earth loop path.

The readings may be lower if the cpc is connected to bonded metalwork along its route but this would still be the resistance of the cpc when in use and so is correct (assuming there are not faults on the circuit).

 

[Pete999]

Hi guys

ive not done any real testing on commercial jobs other than fault finding etc and was wondering, when dead testing lighting circuits would r1+r2 be accurate as the r2 will most probably not run the exact same route as the r1 with more connections etc so would you do an r2 flying lead method?

Thanks

No I'm not going to say it, oh what the hell it's R1+R2 not r1+r2 signed pedant

 

[dingledong]

Ooooooh

 

[smity]

No I'm not going to say it, oh what the hell it's R1+R2 not r1+r2 signed pedant

Ever so sorry I am surprised you understood what I meant :stooge_curly: I think I was over thinking the R1+R2 a little, thank you for all your answers. Muchos appreciated.