Had the DNO out to a service head issue a few years ago and got to talking about earthing and he mentioned a job he got called out to by United Utilities the customer complained to UU because her cold water was coming out of the tap quite warm, turned out that one of the supply cables close to the water main had a fault on it and it caused the metal water pipe to heat up and warm the waterTrue story from a DNO friend of mine. They lost neutral in the centre of Truro shopping centre. First reports were of gas appliances going haywire, so gas called out intially. By the time DNO got there, the gas pipe, when they dug down to find the electrical fault was glowing red hot!