Plumbers Public Liability Insurance Public Liablity Insurance (UK)?

Public liablity insurance (UK)? - plumbers public liability insurance

I'd be a plumber in the morning, which separates the main energy source for electrical work showers, but now no electricity in the house could. He called his electrician and said that the major repair of defects or faults of the board at my expense. Can I ask you to point out that in their coverage of liability insurance? Thanks