Talking about light circuits ---
Anyone ever had anything to do with power in rented premises in a shopping centre??
Well that is a nightmare!
My wife had rented premises for a business she was running. A single power board in the shop, fed from TWO completely different DBs in the complex, unlabelled, one 3 phase, the other single phase, all to a common set of CBs, with a common neutral bar.
The Air conditioning was forever "tripping" the E/L, so was the outside signage and the "emergency light circuit".
Want to guess what the Property owner electrician did to "solve" the problem?
Well he simply bypassed the E/L with all the pesky circuits that were "tripping" the E/L, that's what !
We closed the business and a legal letter war including the OHSA people was still raging after 3 years ----