Testing help

[rob121]

Morning all!
Just completed my two jobs for my NIC assessment. Confident in my work and all of my test results etc. Anyway assessor had a cancellation so has booked me in for this friday so just wanted to double check a few things that are playin on me a bit. Nothing major but just wanted to check before he comes out.
1)When doing PFC ive always done it straight after Ze obv with earth connected but with the system still isolated. Is this correct as in all the NIC books it shows the main switch on? Cant see how it would effect the readings though.
2)I see on a lot of threads here that the assessor asks them to do a cont reading on the bonding. Should I disconnect from MET for this? I never usually do is the cable looks in good condition and I get a low reading but wanted to be sure.
3) Lastly. When doing R1+R2 on final circuits (excl ring), Ive always been taught just to use a fly lead from the earth strip in CU to each CB individually. Is this correct or should I be disconnecting the earth for that circuit?

Sorry if the questions sound stupid. Think its just me worrying as the assessment is so near.

Thanks for taking the time to reply

Rob

 

[Sintra]

Morning all!
Just completed my two jobs for my NIC assessment. Confident in my work and all of my test results etc. Anyway assessor had a cancellation so has booked me in for this friday so just wanted to double check a few things that are playin on me a bit. Nothing major but just wanted to check before he comes out.
1)When doing PFC ive always done it straight after Ze obv with earth connected but with the system still isolated. Is this correct as in all the NIC books it shows the main switch on? Cant see how it would effect the readings though. Keep main switch open (off) for PFC.
2)I see on a lot of threads here that the assessor asks them to do a cont reading on the bonding. Should I disconnect from MET for this? I never usually do is the cable looks in good condition and I get a low reading but wanted to be sure. Keep it connected to MET and use a wander lead reason being if you disconnect it how do you know it is reconnected properly without testing again.
3) Lastly. When doing R1+R2 on final circuits (excl ring), Ive always been taught just to use a fly lead from the earth strip in CU to each CB individually. Is this correct or should I be disconnecting the earth for that circuit? Fly lead from earth bar is fine.

Sorry if the questions sound stupid. Think its just me worrying as the assessment is so near.

Thanks for taking the time to reply

Rob

^^^^^^^

 

[johnboy6083]

PFC should be carried out with bonding and CPC's connected, as any parallel paths will lead to less impedance and increased fault current. With R1 plus R2, I usually link at the load end, and test at the board, but that's cos I've got either a mate or apprentice with me. I always disconnect the CPC, to ensure ive terminated them in the correct place, and also, as I'm often in industrial environments, even if the CPC was broken, I'd still get a reading through parallel paths. Even though it's permitted to use extraneous metal as CPC, I don't include that in measurements ( apart from Zs) as it can often be removed by other trades. Bonding can be measured with one end disconnected.

 

[telectrix]

1. sounds right to me. 2.&3. i would disconnect to avoid any possibility of parallel paths affecting the readings.

 

[rob121]

Brilliant cheers lads. So when doing PFC leave the switch locked off. So when doing R1 R2, would it be better to take the cpc out and connect to the line with a block?
One spark I used to work with connects the cpc in the top of the breaker as he didnt like using a fly lead after it flicked itself into the supply side of the main switch. Gave him a bit of a frieght I reckon!
Cheers again,

Rob

 

[Deleted member 26818]

I prefer to connect the CPC and Line together at the CU.

 

[Bromd123]

I was taught at college that using the flylead option is fine but my boss prefers me to disconnect and use a choc block as one lad that worked for his once livened up the board without taking out the link (not good)

Dave