Installed pv system in customers house, all went well didn't even need to kill power as there was spare breaker in board( lucky). System was up and running in house with no problems, happy customer, so I thought. Got home( 57 miles later) and I get phone call from office to say mr! Had problem with his power.Phoned customer and asked what the problem was. He said the power just went out, I asked him the last thing he plugged in , the hot tub he says . Told him to go unplug hot tub and reset rcd, , All worked fine so I explained there may be a fault with hot tub. He wasn't having it !!and I had to drive back . Found fault on downstairs ring( which hot tub was connected to. Spent nearly hour tracing ground to earth fault which was gas fire place with melted flex !!! With that fixed plugged everything back in and reset rcd ( still tripped out!!! Arrhhh.. Unplugged hot tub and reset rcd no probs.. Explained hot tub was at fault. He wasn't having it and I at last resort i up rated his rcd . Still didn't work. I left explaining that his hot tub was at fault and asked him to bring out independent spark/ hot tub engineer to diagnose fault, and If I was to blame in any way I would cover costs.. Never heard from them again. And to boot I was tank of fuel down rcd and a few hours labour.. Nightmare !! ps it was an inflatable hot tub. Still to this day think he was just trying to get some money off his system!!