# 120/240v Three Phase High-Leg Delta ?



## Seattlepro (Jul 28, 2009)

I think I have a 120/240v Three Phase High-Leg Delta service panel that has some issues. I think it is a high-leg service because its a small mechanical shop located in a residental neighborhood giving me the idea the Power Company didn't have a Three-Phase 120/208 service transfomer to feed this mechanical shop. I have three isulated wires coming from the meter box that terminate to the three main lugs at the top of the panel and then a bare copper wire that connects to a what looks like a grounding strip at the bottom of the panel. However on that grounding strip is some neutral wires (white) and some (green) equipment ground as well, (pretty sure thats a NEC violation). Here is the confusing part there is no orange striped tape on the high leg and no voltage on the B phase. Anyway this what I come up with when I attach my Voltage meter to the terminals.....A to C I get 240v, A to B nothing, B to C nothing, A to ground I get 120v, B to ground nothing, C to ground 120v. I know there used to be voltage on the B phase because there are (2) 240 volt 2 pole breakers that are not supplying the 240v outdoor lighting and a 240v air compressor in the shop that used to work. So I thinking I have a problem with B phase, but has anyone ever had a failure of a phase from the service transformer (on the pole) to meter and then to the panel? Is there a way for me to test a faulty phase with out breaking the seal of the meter box to pull the meter and check? Am I missing something here? Any help would be great, because I don't want to call the power company if i don't have too. Thanks :thumbsup:



PS I know this is not a Three phase 120/208v service, I have been a comercial/service fleet electrician for 10 years now and worked on lots of three phase 120/208v services.


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## RePhase277 (Feb 5, 2008)

Sounds like B phase is dead. Call the power company and have them chack the transformers. If it is a high leg system, there won't be any single pole breakers on the B phase.

And, having the grounds and neutrals on the same bar is fine if this panel is the service equipment.


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## Seattlepro (Jul 28, 2009)

*update*

Yes the B phase was dead!!!! POCO pulled the meter and the B phase terminal on the load side of the meter had completely fried off the lug. Lineman said over time the jaw of the socket became loose and heated up until it completely burned up and melted. For how expensive meters bases are, they sure do fail.


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