Posted By Glyn Atkinson
From thirty years in a similar trade where temporary electrical isolations were made, I can see where your guy is coming from , but hasn't fully completed what is usual practice for many areas fo electrical work.

Temporary connections have to be done, so the isolation is made first, along with testing for dead of any connections that will be open ended and made safe.

The correct size of connector block is used to hold all cables being left open ended.

Insulation tape is then used to cover all areas of that block to ensure that curious hands cannot connect with live terminals.

The next step is to write out on a label or card where all the connections went to and originated from and leave that in with the cable(s), all wrapped up in a clear plastic bag that is clearly marked up so that the switchboard fuse feed / phase used is known to the next person working on these connections.

Often the bag and cable are then wrapped up and held in a tied helix away from the construction work - ie tied up to a roof girder or above a false ceiling until required again.

I keep house first fix electrical runs clean in this manner but left in the box prior to the plasterer covering all of the screw holes in the socket boxes.

I don't know if this method is written down as good practice any where, but is taught (or used to be)as a safe way to temporarily keep cables in a live but safe manner while other works are carried out.

Re-testing of the cables via the connector block ends must always be done prior to re-using the cables again with isolations to circuits.