Basically no. They must be competent. That's it.

NICEIC/NAPIT are generally more geared toward the domestic market, with a smaller proportion of their Members working on commercial/industrial. ECA is for larger Companies, being a Member could show they are competent, but it isnt certain, as Companies registered with NICEIC can have one Employee who is the Quality Supervisor, and is ultimately responsible for the work, but, the workers need no accreditation, so a labourer could do the work with the QS signing it off. It does happen, I've worked on sites where there has been no supervision of a number of workers, none of whom had more than the most basic of electrical qualifications.

The ability to know what they are doing is in the correct way, and testing the work afterwards to make sure it is safe is more important than being a member of a governing body.

Your Insurance Company may differ in their views

The work is covered by CDM Regulations (regardless of whether or not it is classed as 'maintenance').

The Client has to appoint a competent contractor to do the work ... the Contractor cannot start work unless they are satisfied the Client knows their duties under the Regulations, and has appointed, where necessary, competent persons to fulfil their duties under the Regulations.

Now we can debate whether being a member of a competent persons' scheme, or holding a C&G qualification is sufficient to demonstrate competence.

The Client has to appoint a competent contractor to do the work

could the client use their own in-house staff, if they have they have the appropriate abilities?

   - Andy.

AJJewsbury said:

could the client use their own in-house staff, if they have they have the appropriate abilities?

Under CDM, they are still the 'Contractor' ... regardless of which legal entity undertakes the role. Similarly, a single organisation (or even 'individual human person') could theoretically be Client, Contractor and Designer.

Under CDM, they are still the 'Contractor'

Ah, OK - thanks. A new meaning of the word "contractor" I wasn't previously aware of! I can see that's that sort of short-cut that's often used in some texts, but also see it being misinterpreted by the casual reader...

   - Andy.

Yes, even though it seems a little odd - many disputes are between client and contractor.

CDM Regs 2015, R2: Interpretation

“client” means any person for whom a project is carried out;

“contractor” means any person (including a non-domestic client) who, in the course or furtherance of a business, carries out, manages or controls construction work;

“designer” means any person (including a client, contractor or other person referred to in these Regulations) who in the course or furtherance of a business—