C&G 2391 Inspection and Testing Lighting?

Many questions seem to include either a PIR or else discharge lighting. From this I have come to the conclusion that the person setting the question is wanting an insulation test to indicate that the phase and neutral need connecting together to prevent damage.
Discharge lighting generally have a choke to limit the current flow, this creates a reactive component which is reduced by fitting of a capacitor. If you check the rating of capacitors fitted they are normally rated at 250Volts. Testing with a 500Volt insulation resistance meter could damage the capacitor.
PIRs in a circuit contain electronics so should not be tested phase to neutral.

So how would you do an insulation test on a lighting circuit?

• Disconnect circuit from supply and verify circuit is dead using approved method outlined in GS38
• Check that the testing will not create danger to persons, livestock or property
• Link together the phase and neutral
• Check your instrument or it's leads are not damaged.
• Select 500 Volt.
• Securely clip one lead to the earth bar
• Prove connection by testing to another earth terminal, this should show 0.0 megohms or short circuit
• Clip to the phase/neutral connection and press test, wait for a steady reading and record.
• Allow the instrument to remain connected to discharge any stored charge created by the test.
• If test is greater than 2 Meg ohms, disconnect leads, reconnect phase and neutrals back into respective places, restore power.
• Tests of under 2 Megohms would need further investigation but is not a fail as this is below 0.5 Mohms.