Spark123 said:
Hence the importance of agreeing and recording the extent and limitations of the inspection.
Are you saying if you did a PIR in a factory you'd want to disconnect every piece of current using equipment to do IR testing?
The previous discussion was regarding flourescent lighting and ways of disconnecting them, I gave a solution if a particular type, there was disagreement over whether the chokes would cause problems or not.
Obviously you work out how you will go about testing and split it up accordingly but no complete circuit under test should be compromised by only carrying out part of a test.
Lighting is difficult in that it can be hard wired and you still need to test the switchlines up to the fitting, this is where removal of incandescent lamps, flourescent starter switches, local fusing etc comes in (you may have to rig temporary lighting up whilst doing so).
As for All current carrying equipment, each circuit has to be tested on its merits and if possible isolated from the equipment pulling local fuses if necessary(negotiation must be carried out first to determine what implications are involved).
Parts of an installation that don't get tested cannot be included in any certification so I leave it up to you to decide, personally I would let the customer know what i was unable to test and for what reason and another visit may be in order but to sign off an installation i would only be happy once all circuits had been completely tested.
One final thing i'd like to add is don't take on more than you can chew would be my advice to the OP if a big complex installation it may be better to leave it to a specialist firm and have enough labour not to cause too much disruption.
Easy enough to test in domestic premises but more complex with factories, office blocks etc.