There are ways to do this safely but in asking the question you show that you are not competent to do so (no offense meant), like others I will not discuss the correct procedures over a forum as at your level of experience and training you must follow the safe isolation root which can only be done legally by contacting your energy provider and getting them to assist in the power down.
This sight is to give good legal advice so try not to pull us for doing just that - you teach your kids to use Pelican crossings safely and would never tell them to cross the road between parked cars for obvious reasons yet we all do it because we are aware of the risks and look for them but not advisable to teach a child this.....kinda the same thing, so cannot advise you further than already has been.