Stinger Leg

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Shannon Freehauf

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United States
Hi all, new to the site. Just had a question about the stinger leg.
I am working in a trucking yard where the owner wants our company to run a couple of new 3 phase plugs for compressors. There is a 3 phase panel with a stringer on the B phase. In this panel there are 2 pole breakers that are sitting on the a,b phase or the b,c phase. also there are 3 pole breakers that are sitting with the stinger on different phases, 1 is on the c phase another is on the a phase. it seems that it is very random. I will have to make some moves to these breakers to get the new breakers in, but just wanted to know if this could be a problem.
 

Dennis Alwon

Moderator
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Location
Chapel Hill, NC
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Retired Electrical Contractor
The stinger can't move from phase to phase. If the high leg is on the B phase then it will remain there however someone may have marked it incorrectly.
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
Could be a problem if any loads whose breakers use 120V for controls. Highly unlikely unless you see a grounded conductor leaving the panel in the same conduit or cable. Also on the 2 pole breakers you move you want to make sure the load doesn't have a phase converter on the other end, again also highly unlikely since the facility has a 3? service.
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
And auto transformers. When bucking or boosting 3? one ungrounded conductor hits the windings but also passes through unchanged. Want to be sure where the 208 is going there also.
 

tx2step

Senior Member
Be sure that you double check motor rotation on any 3 phase motors fed by any 3 phase circuit breakers you move -- the process of moving the CB & removing, rerouting, extending and reconnecting the load wiring might cause you to accidentally change motor rotation.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
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Electrical Engineer
The high leg has to be on B/center phase in the panel, but it doesn't have to be in the center hole on a three pole branch circuit breaker.

Could be a problem if any loads whose breakers use 120V for controls. Highly unlikely unless you see a grounded conductor leaving the panel in the same conduit or cable. Also on the 2 pole breakers you move you want to make sure the load doesn't have a phase converter on the other end, again also highly unlikely since the facility has a 3? service.
I have heard, anecdotally, that there are a few utilities and local jurisdictions in the country (Texas comes to mind) where the High leg is required to be C phase, which contradicts the NEC. But as we all know, LOCAL rules trump NEC rules.

So Shannon,
It is up to you to confirm exactly WHICH phase in your panel is indeed the High (Stinger) phase. It is only High with reference to the Neutral, it will read 208V phase to N, instead of 120V. So if you are SURE it is Phase B (a good electrician confirms with a meter, rather than trust a previous person's work), then the only concern you need to worry about is regarding SINGLE pole breakers not plugging into the B phase, and if any of the 2 pole breakers are going to loads that require the Neutral as well as the 2 hot lines.

So for example on that last issue, if you have a 12-3 w/G NM cable going out of a 2 pole breaker to an outlet where a cloths dryer is plugged in, the clothes dryer may be designated as 240V, but INTERNALLY, because you ran the Neutral conductor to it, it might be tapping off of one hot line and Neutral for some 120V controls. THAT circuit must not stab into B phase, because if the internal connection is to that hot line, it will fry the controls.

So the safe bet, if you don't know for sure, is to not plug any 2 pole breakers into B phase either, only 3 pole breakers tie into B phase. That might get tricky when adding circuits, but it's important.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
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Licensed Electrician
I have heard, anecdotally, that there are a few utilities and local jurisdictions in the country (Texas comes to mind) where the High leg is required to be C phase, which contradicts the NEC. But as we all know, LOCAL rules trump NEC rules...
Every high leg service I have worked on the high leg is on C phase at the meter and rolled over to B phase at the service disconnect.

Back in the '70s the high leg was on C but I wasn't working, I was still playing army man in the back yard.
 
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