With the impact on business, I just don't get why folks don't go rcbo throughout.
My visit to a premises the other day was based on Customer (friend of Wifey) complaining their leccie bill was too high -"that can't be right, I'm paying for the whole building ...". I attended but after 10minutes I got bored with looking at tails and meters (no obvious problem), I went up to the kitchen and I could hear water running. Washing up? Maybe. Anyway it turns out their dual immersion was busy day and night trying to keep the tank water warm as it poured out the (failed open) prv into the tundish. "How long's this been going on I ask." ... "It's always made that noise " she replied. Plumber got a job and I got a coffee.