Where would I find the info for the test to carry out PRIOR to carrying out works to ensure the circuit is adequate?
Which test would you carry out then prior to carrying out any works on a circuit?
Let's say an existing lighting circuit, and someone wanted an extra light with a switch for that light and also a ring circuit which they wanted to add an extra socket to.
As Lucian says, there is a certain business trade-off in how you should best tackle a job, and some of that will come with experience as you get to know the range of customers and the sort of installations you are going to work on.
It is quite risky to quote time & cost without seeing the installation, but often when you take a quick look (or get the customer to send some photos of the supply/CU and the bits they want changed, etc) you will have an idea if it is risky to offer without testing or not.
So for a big job like a CU change you
really want to know what you are getting yourself in to, so many electricians would insist on an EICR first, either as a step before quoting (if it looks like a troublesome job) or as the initial stage of the work if it looks routine.
A very good guide as to what things might be wrong that would need rectification as part of any work (big or small) is available for free as the Best Practice Guide #4 here:
Electrical Safety First produces, in association with other industry bodies, a range of Best Practice Guides which provide definitive information and guidance on a range of technical subjects.
www.electricalsafetyfirst.org.uk
For smaller jobs, such as a light change or extra socket, you probably don't need to test before quoting, unless the age or general condition/abuse over the years gives you cause to worry. But it is best to do at least a quick check before you start in case there are surprises, then the customer does not get the impression you are trying to make up for mistakes you made. I.e. you can be up front if you discover a problem that is possibly costly to fix (e.g. open or missing CPC on lighting where it might be in a hidden junction box somewhere).
It may not change the job outcome/cost. But at least they should feel you are doing it professionally by checking for safety first and letting them know, rather than doing the work and then trying to explain why it was actually broken before you touched it.
