The RCD/RCCB should be able to protect this kind of problem. Incase E wire doesn't do the job. All the house now should using RCD/RCCB. Try check your DB box that you always call ELCB.

I m using istant water heater. And I knew I cannot rely on the heater elcb. That left my house just 1 device to protect from the DB box. So I install another RCD in the bathroom ontop the heater.

Here is the RCD device that I install ontop the heater inside the bathroom. It exactly for prevent electrocution and suitable for bathroom which wet enviroment. Can be use for anything.