Unless there is a chance of the AC live connecting to your ground plane directly I don't think that you need worry. If the AC live could connect to your ground plane wiring, then you don't want to stop this reaching earth at all.
If your house is wired correctly, and that you have suitable fuses/circuit-breakers, and an efficient earth circuit, there should be little chance of any danger in the event of live leaking to earth. Electricity will prefer to take the path of least resistance, so unless your ground plane wiring is its best choice to reach a good earth, you should be OK.
I think that good fuses and/or circuit breakers to protect your equipment would be your best protection.