I don’t see this often on residential probably my 3rd time in 18 years
I see that occasionally on multi-unit condos, but never on a house…
What is SI ?
I need a list of abbreviations.
I can’t remember them all.
Typo large fingers small key pad;-)
It looks like 3 phase. Wonder what the residential application would be?
Any grow lamps or drug operations inside?lol
I had a house (a small house) with that. Previous owner was a welder…
This house had two A/C units that were 3 phase but nothing else it originally had 3 phase water heaters but had been converted to gas. Home built in 72 and was more than likely total electrical, gas line was installed at a later date
Haha 
I had my weighted gloves on when I typed it 8)
Correction made…
I don’t see it often but it does happen for 3-phase motors and kilns.