Sequence of testing in BS7671?

[Haydenr25]

Can anybody tell me the sequence of testing that's stated in BS7671? At college I've been taught CRIPES, which is:
Continuity
Ring final continuity
Insulation resistance
Polarity
Earth loop impedance
(functional) Switching

Why are these carried out in this specific order?

 

[ChrisElectrical88]

The sequence only applies to initial verification. Have you got guidance note 3?

 

[Haydenr25]

I don't own GN3, it's for an assignment on my level 3 2365 course. Books are at college and I'm doing some studying over the weekend. The assignment does specify an electrical installation being tested before being put into service, I'm pretty sure that covers initial verification

 

[Haydenr25]

I don't own GN3, books are at college and I'm doing some studying over the weekend. The question covers initial verification as it states "an electrical installation being tested before put in service"

 

[Lucien Nunes]

Think about hazards or false readings that might occur if you started with tests at the bottom of that list and then had a failure of a test near the top.

E.g. If you do the insulation test before continuity, how do you know your IR test is reaching the whole system? If you energise before IR test, how do you know you haven't got a damaged cable that will go bang? Etc. etc.

Each test builds on the previous one having passed, to give correct results without the test causing danger.

 

[guest119]

r1 + r2 to start with gives you continuity and polarity and ensures/confirms you are testing the right circuit.
Imagine energising a circuit for the first time. Megger good, all over 299megs, energise, go to circuit end with loop tested and find its dead.
Is the circuit broken? Are you on the right circuit? Is somebody somewhere being plated?

 

[SirKit Breaker]

Continuity of protective conductors (inc protective bonding conductors).
Continuity of ring conductors.
Insulation resistance.
Polarity, this done by default if you use R1+R2 method for continuity.
Earth loop impedance
Additional protection (RCD tests)
Functional testing.

If you can't or struggle to remember the sequence, it is laid out in the correct order on the Schedule of Test Results, this is one of the tips i give out on the insp/test courses.

But in any case, if you getting your head around testing, then GN3 is a must have.

Cheers………………..Howard