NIEIC inspection

[tom-the-sparky]

Hello everybody

Ive got my niceic inspection soon. On my recent fuse board change and test i completed Zs tests for each circuit but only calculated R1 + R2 (apart from the ring mains) IS THIS OK? Also if anyone has had the niceic guy come out, any words of warning?

Thanks

 

[IQ Electrical]

If I had an assessor round and he asked me how I'd established my Zs values and I said I measured them, would he contradict me and say that was wrong?

Could I fail my assessment on this issue, even though I could back-up 'measuring' Zs with GN3 and the 2391?

Yes, if you told him you'd measured Zs on your lighting circuits from the top of a pair of 12-tread steps with a 3-lead instrument.

They're concerned about safety, if you follow the usual guidelines and use test gear in good condition to GS38 then they can have no complaints, as you already quite rightly said, the NICEIC or A.N. Other do not write the reg's or Guidance Notes.

I can just imagine my assessors comments if I told him I gave up measuring Zs values on the grounds of safety!

 

[Des 56]

Niceic regulations are emerging once again

Shall we pen them a few words,(tactfully) because they are sensitive souls,that contrary to their belief,others are responsible for the regs and they are just followers

 

[brucelee]

hi all
On all the courses I have just done including 2391 they say to calculate all except radial and ring final circuits with a suitable plug in lead. I even was told to do it this way for practical assessment and then compare to rule of thumb max measured tabulated 80% values In GN3 , they just say for safety reasons and whats reasonable not to put yourself in danger with regard to Elecy at work regs e.g. They state not to work live unless in all circumstances its unreasonable to work dead and in all circumstances its reasonable to work live and safety precautions are taken to prevent injury by using suitable PPE which is a statutory document and supersedes non stat and codes of practice and also with regards to Health and safety regarding working at heights as IQ electrical said e.g 12 tread step ladders , but at same time we had questions asking how to conduct an earth fault loop impedence on a lighting circuit in a commercial or industrial premises and also says in all the non statutory documents either way is acceptable .It Seems there is lots of contradictory info regarding different methods. too much confusion? As wayne has said this is how gn3 says to carry our Zs on a pir . The tutor also said Zs is the most important test as it not only proves there is a continuity in the loop, but also confirmes ,polarity and voltage and to ensure the Zs is low enough for a sufficiently high enough fault current to ensure the protective device will actually operate in the required time to meet max disconnection times, but again tutor still said to calculate as this is the true value where possible, measuring not accurate as it includes parallel earth paths from the main protective bonding conductors etc etc ?????????????? confused or what please dont shoot me this is only what ive been taught by my betters
I am with lenny and you guys, but if asked i am with calculating lol so do i or dont i measure that is the question?????????

 

[IQ Electrical]

We have different scenarios for City & Guilds, scheme providers and the real world!

Personally, I measure everything and I've never been corrected in this regard during the many annual assessments that I've endured as QS.

 

[Sintra]

We have different scenarios for City & Guilds, scheme providers and the real world!

Personally, I measure everything and I've never been corrected in this regard during the many annual assessments that I've endured as QS.

Same here and never once has it been questioned.

 

[olly w]

I'll get shot for this but in my opinion earth fault loop impedance is the most important test of all.

All the conditions are real with this test.

The voltage being used by the test instrument to calculate it, is the actual voltage that is at the test point.

26 amps is put down the earth to prove all connections are sound.

Polarity is proven.

And as said earlier it proves the over current protective device will actually operate in time.

By the way on a new install I think all tests should definately be carried out.

 

[Des 56]

By the way on a new install I think all tests should definately be carried out.
Yes indeed
The only weakness in full reliance on Zs tests, is the scenariowhere there are metal services, and later conversion of those services to non conducting materials, it could expose the user to potential danger if there was no cpc continuity

 

[olly w]

Yes indeed
The only weakness in full reliance on Zs tests, is the scenariowhere there are metal services, and later conversion of those services to non conducting materials, it could expose the user to potential danger if there was no cpc continuity

Whoever removes those services should be informing the user of the potential danger and advising the user to have the relevent checks carried out.

Don't forget that once upon a time it was standard practice to use the main water supply as the earth electrode!

 

[martysparky]

And Nic accept just Zs if stated on cert Zs only.

 

[brucelee]

when we did the practical for 2391 when calculated the radials we had to write Zs calc in the remarks on the schedule of test results for the appropriate final circuit

 

[Guest123]

When I did my 2391-10 we measured it, I also did the practical part of the 2400, again it was measured.

I've been doing it since I started with no problems and will continue to do so.