1 phase service and 3 ph. equipment

[Toros]

:happysad:
my Clients says,
he runs 3-ph. equipment off the existing 200A 1 ph 120/240v and 100A , 1-ph. 120v (adjacent installed) services.

by combining both

is this true???

 

[LarryFine]

Conceivable if 240v panel (208v, actually) on, say, phase A and B, and 120v panel on phase C, but not Kosher. Circuit must be derived from a single service/panel.

 

[kwired]

Conceivable if 240v panel (208v, actually) on, say, phase A and B, and 120v panel on phase C, but not Kosher. Circuit must be derived from a single service/panel.

I agree, is possible if they both originate from same three phase source.

As Larry says, more likely a 208/120 source. If it were 120/240 delta then one of the single phase services has a 120 to neutral line and the high leg on the other line - that won't work out so well unless it only feeds 240 volt loads or you were careful to put all 120 volt loads on the one side.

add: I suppose if each service were fed from a different primary phase - you can possibly get enough phase differential that it works, but probably is not a true 120 degree differential and the more torque you demand the less likely a motor can deliver it.

 

[Tony S]

I can see how this could possibly work as a high leg open delta. What I can’t see is how any code or regulation in the world would allow it. It’s downright bloody dangerous!

 

[Jraef]

As our member Jim Dungar says in his signature line,

"Just because you can, doesn't mean you should."

In this case the concept of "can" applies only to the possibility of it functioning under the right set of remote possibilities. Nothing else about it is safe, legal, reasonable, or proper.

 

[gar]

190423-1025 EDT

The original post asks the question of can? The answer is yes, but not based on the title.

I could run an extension cord from one of my next door neighbors, preferably thru an isolation transformer, and immediately have a 120 V open delta supply.

The correct way is to have the power company add a second transformer to generate the second phase. Several neighbors have this setup.

If one is to follow the title, then no, unless some power conversion device is used.

.