David
To be blunt it annoys me ( as an electronics engineer with 40 years experience that has included working on marine and industrial control systems and life critical communications system ) that the "difference" between "earth" as in the CPC and earth as in true ground is apparantly not fully understood. I accept that there will be confusion as at one time the CPC was earth ( true ground ) then it became a signal wire to operate a voltage operated breaker if there was any earth fault. But this rapidly went out of fashion when it was pointed out that accidently connecting the CPC ( signal wire ) to true ground immmediately reduced the safety by bypassing the coil in the breaker. Then we got the PME system where "earth" is the neutral and this can be forced ( by network un-balance or faults ) to be several (or even many volts from true ground. Broken incoming neutral and the CPC can be at 230 volts above true ground. Touch an equi-potentially bonded outside water tap when the CPC is in that state and there is the possiblily of a fatal shock. Why no device to detect that the CPC is above ground voltage. OH DEAR full circle back to voltage operate breakers.
Confusing to say the least and as a compromise maybe not the best.
To be blunt it annoys me ( as an electronics engineer with 40 years experience that has included working on marine and industrial control systems and life critical communications system ) that the "difference" between "earth" as in the CPC and earth as in true ground is apparantly not fully understood. I accept that there will be confusion as at one time the CPC was earth ( true ground ) then it became a signal wire to operate a voltage operated breaker if there was any earth fault. But this rapidly went out of fashion when it was pointed out that accidently connecting the CPC ( signal wire ) to true ground immmediately reduced the safety by bypassing the coil in the breaker. Then we got the PME system where "earth" is the neutral and this can be forced ( by network un-balance or faults ) to be several (or even many volts from true ground. Broken incoming neutral and the CPC can be at 230 volts above true ground. Touch an equi-potentially bonded outside water tap when the CPC is in that state and there is the possiblily of a fatal shock. Why no device to detect that the CPC is above ground voltage. OH DEAR full circle back to voltage operate breakers.
Confusing to say the least and as a compromise maybe not the best.
