delta breaker
- Thread starter kimrichi
- Start date
- Status
- Occupation
- Licensed Electrician
A delta breaker was a way to bring three phase power to a single phase service.
They are not allowed anymore because they are obsolete and somewhat dangerous.
They are not allowed anymore because they are obsolete and somewhat dangerous.
as recall, it was a hybrid "two pole" breaker (to legs connected to the buss) with a third pole added that was supplied by a conductor (somewhat like a GFCI neutral conductor).
This allowed the breaker to be used in single phase panel with the 3rd phase connected directly to the breaker.
At one time they were common in small commercial buildings with limited 3 phase loads such as a "Mom and Pop" grocery with one three phase cooler.
(I believe some had a "Line" lug rather than a conductor)
This allowed the breaker to be used in single phase panel with the 3rd phase connected directly to the breaker.
At one time they were common in small commercial buildings with limited 3 phase loads such as a "Mom and Pop" grocery with one three phase cooler.
(I believe some had a "Line" lug rather than a conductor)
Last edited:
kwired
Electron manager
- Location
- NE Nebraska
There is a picture of one in the following link I copied from another thread on this topic.
http://www.electrical-contractor.net.../16#Post152376
http://www.electrical-contractor.net.../16#Post152376
- Location
- New Jersey
- Occupation
- Journeyman Electrician
How would you get the 3rd phase into the single phase panel?
I have only seen two such installs (hard to believe I didn't install one)..
Both were "service" panels and the third phase was brought from the meter straight to the only "delta" breaker in the panel.
One of the many reasons they were later deemed "unsafe"
Both were "service" panels and the third phase was brought from the meter straight to the only "delta" breaker in the panel.
One of the many reasons they were later deemed "unsafe"
Wagbag
Member
- Location
- Palo Alto, CA, USA
Wagbag
Wagbag
Your question is interesting. Let me direct you to a 'must have' text book if you are an electrician, it is the Amerian Electricians' handbook by Terril Croft and Wilford Summers. Delta breakers/panels are still in service today and are unique and wonderful equipment. If you are unaware of how they work and you need to have maintenance performed on a panel, call up an electrical contractor and have them take care of it for you. I presume your life is of value to you and calling a qualifed electrician might just save it.
Wagbag
Your question is interesting. Let me direct you to a 'must have' text book if you are an electrician, it is the Amerian Electricians' handbook by Terril Croft and Wilford Summers. Delta breakers/panels are still in service today and are unique and wonderful equipment. If you are unaware of how they work and you need to have maintenance performed on a panel, call up an electrical contractor and have them take care of it for you. I presume your life is of value to you and calling a qualifed electrician might just save it.
A panel being serviced by a Delta is not part of this disscussion and IMO there nothing wonderful about a delta breaker. I installed three in the seventies, two were replacements and one was because the facility had one available and it suited their need.
Roger
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
They definitely are not wonderful, which is why the NEC has not allowed them in new installations for almost 40years.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
The only time I have ever replaced one was at a plant I worked at that had a high leg delta service and had several single phase panels fed from "A", "C" legs to serve the 120/240 volt loads, and a couple of them had one of these installed to provide 3-phase for office air units, but that was back in "79 or 80"
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