What a gem! Depending on the slot you used for each SP breaker you could get 0 or 120V and for each DP breaker you could get 120 or 240V (to neutral), really great piece of work - love how the L1 and L2 lines are beautifully numbered, then hacked into a 3-ph panel.
So this wasn't existing was it? Seems that there would be a definite balancing issue for the neutral conductors on most, if not all mwbc's. Another good example of someone knowing just enough to be dangerous.
Seems that if someone was to backfeed the 100 amp breakers as a main, they could have just tied the 3rd bus lug to 2nd bus lug. (Far as I can see, there's nothing on the bus lugs). Or just take the sltrsfy live output of the 70 amp breaker and loop that up to the 3rd bus lug. Would that make it a sub-panel imbedded in the main panel? Not that that matters, this all violates code....
Only one close to that is one I worked on where they had fed a 3 phase panel from a single phase tranformer and jumpering from center lug to right hand lug whole thing was a blooming mess.Another comment, seeing that is a I-T-E panel was jumper still in place on the split neutral? I am assuming its a sub not a main panel, otherwise grounding and grounded are bonded.
Though this is certainly among the least of the problems here, isn't that 100a "main" breaker supposed to be fitted with some type of retaining screw if it is to be backfed like that (in any kind of panel)?
In one case, I saw a three phase panel being fed by a single phase service. The "C" buss was not being used at all - the breakers were located only on "A" and "B". Still not right, but at least someone was thinking about the neutral balancing issue. regrettably, the cover had long since disappeared, so it was all too easy to view the interior .
[This message has been edited by mamills (edited 01-05-2007).]
A couple of years ago I was house hunting and saw one just like this, 3ph panel on a single phase service. They just didn't have any breakers in place on C phase....... If one panel wasn't bad enough, there was a 3ph subpanel in the utility room........