With a 10-in-1 in my pocket and some time to kill I could not help but look at some interesting PLC controlled dimmer(s). I was not there for anything work related.
I was surprised to find one solid state dimmer dimming 4 two wire 240V circuits.
There are 4 # 12 conductors all from the same leg of four 2 pole 20's landing on the one line in lug of the dimmer.
From the one line out lug four #12AWG conductors go to separate 240V resistive loads.
At the dimmer the supply conductors are obviously joined. However each supply conductor originates at a different breaker, however all these breakers are joined on the same bus.
If there is a ground fault all four 2 pole would have to trip. In addition all of the 240V receptacles would have 1 leg energized unless all four 2 pole 20's are switched off.
Parallel conductors ? MWBC ?All kinds of code issues come to mind.
The dimmer is rated for the load.
It looks like a clean professional installation, definitely done by a contractor and inspected.
I was surprised to find one solid state dimmer dimming 4 two wire 240V circuits.
There are 4 # 12 conductors all from the same leg of four 2 pole 20's landing on the one line in lug of the dimmer.
From the one line out lug four #12AWG conductors go to separate 240V resistive loads.
At the dimmer the supply conductors are obviously joined. However each supply conductor originates at a different breaker, however all these breakers are joined on the same bus.
If there is a ground fault all four 2 pole would have to trip. In addition all of the 240V receptacles would have 1 leg energized unless all four 2 pole 20's are switched off.
Parallel conductors ? MWBC ?All kinds of code issues come to mind.
The dimmer is rated for the load.
It looks like a clean professional installation, definitely done by a contractor and inspected.
