Blood on the drill bit
Working on a domestic installation with Clancy, we determined that there was sufficient access under the floor for one of us to crawl underneath and pull the cables in. By one of us I meant me.
Under the floor with a torch, the walls above had been built so that their supporting walls under the floor were the same layout. Brickwork extended from the foundations to support the inner walls of the property, similarly to the external walls, the layout even had gaps where the doors within the house were located.
I was tapping the floor and Clancy was tapping back so we could locate each other’s position to a few inches, Clancy would tap and ask if there were any cables or pipes under that part of the floor.
When we agreed there were not, he would drill a hole and send down the end of the cable, for me to draw it through to the location of the control panel.
This was working well and after about forty minutes we had almost completed the ground floor wiring, next task was the front entrance door, unlike interior doors, this did not have a gap in the supporting wall to indicate its location.
After a lot of tapping and two drilling attempts, I could not see where Clancy was drilling from underneath.
Clancy changed the drill bit for a much longer one and called to me, “make sure you're out of the way as this is a new drill bit and I don’t want blood on it”.
The hole was successful, the cable installed and we went for lunch, when we arrived back, the supervisor's car was parked outside the house, the supervisor came out of the house to meet us and said that all our tools were by the back door, we were not allowed to go back into the house.
It would seem the customer did not like the idea of drilling apprentices under the floor, or the thought of blood spilled if it went wrong.