Garden fire???...for god sakes man...
NOt a very good question.
Who has ever had an electrical fire?
Well....in 50 plus years..I've never seen one being an electrician by trade!!
So if you do...maybe you should have used an sparky to do your work.
The hot water tank and furnace are more of a concern
... Carbon monoxide...fire......gas leak,,,,etc.... the list goes on.