Summary:

Steering gear motor no 1 not able to start when pilot was on board. No.1 motor was from ESB. One service engineer was engaged for SCBA maintenance. He accidentally switched off the No 1 steering gear motor breaker instead of SCBA compressor motor which was next to SCBA power breaker

Corrective Action/ Lesson to be learnt:
To be in contact & check with attending service engineers, strict instruction to them not to handle any of the switches or circuit breakers.

Incident:
Steering gear motor not able to start, when pilot was on board.