Here's a mystery for you. We just spent the weekend at a CC site in Derby. Went out for the day and came back to find no power from the EHU. Nothing had tripped and no fuses were blown. I took our cable out of the socket and put it in another on the supply and it worked, has this happened to anyone else.
Yes this as happened, not to me but to someone else attending a rally that we were marshaling at the time. Their electric supply when connected was working okay but when they returned from a few hours away no electrical appliances were working. They checked the caravan trip switches to no avail so they then came to seek help from myself. My first instinct was that it had tripped at the supply post and sure enough that was the problem but whether a heater was left on in their absence I'm not sure but something must have overloaded the supply as I think it may have been only been a 6 amp power supply.
I've known it happen more than once where some tosser has tripped their board supply, and rather than own up to the site manager, have simply swapped their plug with mine on the same board.