There is always a reason. Not always a good reason mind!
Some folks don't check the CPC integrity, and even if it is OK, checking the CPC potential to true Earth (as what is probably under the concrete floor) is not always done.
My only experience of that was a mate's father's home, said he got shocks from the garage door. Turned out no incoming supply earth to MET connection and recently an electric fire was added that the fixing screw managed to puncture the live. Result was whole house at 230V
No idea if it was just missing at the start, or some muppet had removed it for whatever reason.
Some folks don't check the CPC integrity, and even if it is OK, checking the CPC potential to true Earth (as what is probably under the concrete floor) is not always done.
My only experience of that was a mate's father's home, said he got shocks from the garage door. Turned out no incoming supply earth to MET connection and recently an electric fire was added that the fixing screw managed to puncture the live. Result was whole house at 230V
No idea if it was just missing at the start, or some muppet had removed it for whatever reason.