water pressure / water heater

I had a new water heater installed less than two years ago and the installer left a copper wire wrapped around the pressure relief valve and nom the heater is broken and leaking internally. Should the installer have taken that wire off so if it needed to release pressure it could have - and could this be why my valve to the water softener also exploded? I know I am a plumbing dummie but I really need to know if it's their fault?:wink: