In article ,
Tim S writes:

Yes, you should definitely have certification if offering as a professional
service. It's a C&G 2377-002. I did mine the other month - it's not hard
[1] and is a 1 day course via the IET and a short exam on a subsequent day.
You should not use a pass/go tester (these are for people to do a quick
verification on equipment) - you need to record *actual* numbers on the
inspection sheet (so future inspectors can see if there are any trends
developing).

Here's a pointer (other course providers are available):

http://www.iee.org/Events/Courses/Short/cg2_gen.cfm

I did 2377-001 and 2377-002 at a local technical college
for a quarter of the price IEE charge for just one of them.

Public liability insurance would be advisable (in case someone trips over
you while you are on their premises - that sort of thing).

Another problem you'll find is a number of companies will
insist you belong to NICEIC in order to do PAT testing
but won't care about you being 2377-002 qualified. This
is completely wrong, but it will still be a problem for you.

--
Andrew Gabriel