Air Gap: a physical separation that isolates a connection to a voltage source or potential. Reconnection of physical separation shall require extreme effort, or shall be impossible.
physical act of cutting a 12” to 24” section of raceway/cable. AIR GAPPED.
I can't seem to find anything in the NEC or IEEE and I was hoping I could get some help from this site.
The demolition guys like to see a physical separation between whatever they are working on and whatever they are not (supposed to be) working on. That's where the term 'air-gapped' comes from. We would probably trust a locked breaker, but a visible gap in cables, pipes, etc gives them a visual and definite disconnection from any type of service. I've also heard it described as 'blue sky', although in this part of the world they would wait a long time.
As for standards, I'm not aware of any. The demo guys don't trust normal isolation devices, so the standard becomes 'whatever they will accept'. Most will accept a gap of a few inches, as long as it is clearly visible.
----------------------------------
If we learn from our mistakes I'm getting a great education!
So, everything visible is "air gapped" but the source of power that comes in out of the slab is invisible and therefore left in place. Nice. Like I mentioned, visibly grounded is so much more effective.
I am also with Mr. Scotty. I have also seen that while doing any maintenance people believe what they see. Air gaped between contacts is something which people can trust for safe working.
I have seen people preferring breakers with fuses over MCCB as that can takeout the fuses and put them in pockets while working.