Old single phase breaker for 3 phase

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Arkansas74

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Ozark,arkansas
Hey does anyone here know what they called the old breakes that were outlawed I think in the 70's that was for a single phase panel and had a extra lug for a 3rd wire. I'm looking for a photo to show some guys at work. We were talking about 3 phase motors hooked up to single phase but I don't remember what they call the breaker.
 

don_resqcapt19

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Staff member
Location
Illinois
Occupation
retired electrician
It was called a delta breaker. It had four terminals for wires and two connections to the panel bus. The 4th terminal was for the line side of the 3rd phase. 408.36(C) prohibits the use of a delta breaker in a panel board.
 

iwire

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Massachusetts
You found a Bennie Palmer post. A member who has passed away and I still miss.



Member

Name: Bennie r. palmer
Email: palmerbennier@msn.com
Location: Oregon
Title: Inspector
In Trade Since: 1950
Registered: Oct 2001
Total Posts: 1264



The last delta breaker, I installed, was in the 60's. I think the code first prohibited the use in 1984.
This was a very economical method to operate a water well pump, on farms, and a limited number of 3 phase motors, from a single phase panel board.
The code section read" a three pole breaker could not be installed in a panel with less than three busses". This eliminated the delta breaker.
I don't remember all the reasons for discontinuing this concept. I heard one reason was; the utility workers were installing these in existing services. This was against union work agreements. The last one I installed, was supplied by the utility company.
This procedure started when running water was first in homes. Well pumps with a 3 phase motor worked better than a single phase.
The existing single phase 240/120 transformer could remain in place, and connected. A small transformer, sized by the 3 phase load would be added. The primary was connected open wye, using two phase legs and the MGN. The secondary would be open delta.
This created a high leg, which was run to the feed through pole of the delta breaker.
This high leg would often be only a #10 wire.
This was the first time I used Orange for color marking.
There was some problem with metering this system, I don't know all the details.
I think phase converters caused this systems demise, prior to any code rules.
The decision to prohibit the delta breaker, was either for selling more converters, more 3 phase panels, a jurisdiction dispute, or maybe all the above. I can see no logical safety problem with their use.
I am sure there is no existing services with a delta breaker. Maybe on an old farmhouse somewhere.
IP: 63.21.201.67
 
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