As always in cases like this, I wonder if there is not more to the story.
It just does not make sense. He saw an obstruction, had the power killed, wore protective shoes and removed the obstruction.
What safety rules did he violate?
What is the "approved" procedure that he "should" have followed?
PS: from the BBC sites, it appears that the violation was not confirming that the power was turned off. A safety violation. But enough of a violation to fire the person?