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AM2 and AM2S 10 Stages of Safe Isolation for a 3 Phase Distribution Board (3 Phase Supply) How To

In this video I carry out the 10 stages required for safely isolating a 3 phase supply feeding a distribution board. The video shows you how to lock off, pro...
Isn't there a step missing ?
To my way of looking at it, we've not seen any evidence to prove that the isolator that was locked off is in fact the right isolator. OK, it's true that if it wasn't, we'd (probably) find live power when dead testing. But if there was nothing running to prove that there was power to the board in the first place - e.g. it's mentioned to llisten for machines running down, or look for lights going off, but in the absence of that, how do we know that the board was not already turned off at a different isolator ?

The next question being how to safely prove that. It's one thing if there's an isolator within reach of the board - but normally it might be half way across the factory and you don't want to leave a live board with the cover off while you go to the isolator to turn it off after proving that you did have power at the board first.

If you really really want to maximise safety (apart from switching the power off to the whole site*), wouldn't you want to prove that the incomer switch was working, lock that off, and replace the cover over it's terminals ? That way, even if the upstream isolator failed/was the wrong one/whatever then the internals of the board would not become live.

* As an old school friend of mine found out. I never did hear the whole story, but working in busbar chamber with supply locked off and proven dead, plus backup genny, resulted in such burns (both skin and deep internal) that he was not expected to survive.
 
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