I have again found my name mentioned!
OK, NICEIC, ECA, ELECSA do not require the person undertaking the work to be fully competent in all aspects.
NAPIT, however, seem to, it has not yet been clarified in my eyes, how NAPIT do this for large firms with many operatives.
The NICEIC/ECA/ELECSA do this by a Qualified Supervisor system.
It was a breakdown in the interpretation and implementation of this system that allowed the sad death of Emma Shaw.
Now as far as NAPIT goes, they assess for domestic, commercial and industrial electrical installation works.
However, it seems that they will inspect a few domestic installations, then accredit the contractor for commercial and industrial based on the domestic works.
Now I for one, think this is wrong, and, I am happy to be proved wrong.
However, at this point in time, this is the way I understand this to work.
SO if you use the NICIEC/ECA, you might not get a competent person doing the work, (this is with larger companies, sole traders/one person ltd co. the person must be competent to be accredited), or you could go NAPIT and get someone doing commercial / industrial who has never had this work assessed by NAPIT to check that they are competent to do it.
However, any of these accredited companies can use non-accredited sub-contractors and simply sign off the works.
This goes for sole traders/one person ltd co, and anything up to national and multinational organisations.
The risk however, for smaller companies in doing poor work is greater, as they have a smaller reputation base to "loose".
Full of holes these scams.
TBH the most important membership criteria for all of them is that the cheque clears.