When cleaning my ceramic hob yesterday (wet, but not excessively), I noticed some voltage going through my wet finger when touching the shaft of one of the knobs (I had removed the knobs before). I immediately stopped the work and used the circuit breaker. (And that is what you should do, too, if feeling even the most gently voltage. Really)
- The knobs are mounted right above on the hob, where it does get wet sometimes
- The hob was installed by a professional electrician, but it is an old one.
- The casing is connected to protective earth, but the knob shaft isn't (measured when the circuit breaker was open)
I cannot measure any voltage on the knob shaft, presumably because it has had enough time to dry. But I am wondering: Isn't it supposed to be connected to protective earth, just like the casing?
Because the plastic knob will not always provide good isolation: it's easily detachable, and even when attached, the 1/2 " it provides as a distance from the shaft sometimes gets really wet when cooking.
Should I replace the whole hob?