30/03/2021
So this happened today.
A total of four light fittings that were put in by an unqualified person had the “always active” loop connected to the earth terminal of the light.
Which means for at least the past three years the casing of the light has been live 240V. The equivalent of having a large bare wire in the center of the ceiling of each bedroom in this house.
This home has also had, at least part of the time, been used as a AIR B&B.
Finally the switchboard that distributed the power hasn’t been upgraded since the at least the seventies as they were all ceramic fuses, not circuit breakers or safety switches.
This is a very, very dangerous situation. Not only could anyone touching the light get electrocuted, even with the light switch in the ‘off’ position, they would have received full current of at least 10 amps.
For the record it takes a current of only 0.007 amps for three seconds to stop your heart but it’s usually a current of 0.1 amps for one second that is considered a lethal amount. (N.B. Other factors are also involved like voltage and current path through the body)
Safe to say that the experience is less than pleasant whatever the outcome.
Safety switches are designed to shut down the circuit whenever an imbalance is detected above 0.03 Amps within a period of 0.3 seconds. (e.g. you touch the active or the neutral) which in a healthy human being is faster than a ‘lethal shock’
The lesson from this is don’t do your own electrical work, it’s dangerous and potentially deadly.
Also if you don’t have safety switches in your switchboard, please think about getting them.