4 pole 240 V breaker

[90cummins]

I was shopping for a 240V 3 phase breaker and came across a 4 pole 240V breaker.
Never heard of such a thing!
What would the application for this be?

 

[not2old]

The main breaker in my panel is 4 pole 200A 240V. Don't have enough electrical knowledge to understand why.

 

[oldnslo]

I believe the 4th circuit is for neutral wire. Adds another layer of protection since also breaks neutral leg when tripped.

 

[grsthegreat]

Nope, nope and nope

Those are called quad breakers. Most panels will allow you to remove 1 dual breaker and add this breaker. This will allow two separate 240 volt circuits.

But will generally only work on panels that have a notch in the bussbar.

For instance, a siemens 30/40 panel. Can either take a total of 30 full sized breakers, or the lower spaces can allow for these quad beakers (or twin breakers) to increase to 40 spaces.

Heres a siemens 30/40 panel. See the notches in the lower 5 posts of the copper bus bar.

 

[grsthegreat]

The main breaker in my panel is 4 pole 200A 240V. Don't have enough electrical knowledge to understand why.

Some panels use a 4 pole breaker, but its because each actual breaker was not able to carry the full load. Its just a cheaper way to make a panel. In other words, the left 2 breakers are one phase and the right 2 breakers are 1 phase. Has nothing to do with neutrals.

For example, this panel would feed 200amp through to a mobil home or house, while allowing 4 circuits at this panel.

 

[MAX-24-Dean]

As I recall they were only allowed if they were a factory assembly, meaning installed at the factory.
First saw them in the late 1970' or early 80's. ITE found a way to make a more competitive panel this way. Less cost to manufacture, it gave them a short term advantage in the market for a very short time.

 

[grsthegreat]

Ya, the 4 pole mains are still made and sold, but i hardly see them any longer.

 

[MAX-24-Dean]

Ya, the 4 pole mains are still made and sold, but i hardly see them any longer.

Thanks, I didn't know that they were still being manufactured.

 

[90cummins]

Ya, the 4 pole mains are still made and sold, but i hardly see them any longer.

So you would use it as a cheater breaker if you run out of space???
90cummins

 

[grsthegreat]

So you would use it as a cheater breaker if you run out of space???
90cummins

Yes, but not really cheating. As long as the buss is notched. Siemens makes breakers for panels that arnt notched, but there expensive. The NEC did away with max breakers allowed in panels awhile ago.

 

[ponytug]

I'm not sure what to say. They are quite common around here.

We have more than a few tandem quad breakers, with several different uses. Some are for dual 240V circuits (tandem), some are on multiwire branch circuits (aka shared neutral) that under current code are required to throw both hots, hence the pins and sleds.

We also have a single main breaker, followed by a quad 200A (4x50A) breaker protecting the two panels in series downstream, which each have 200A single breakers as whole panel protection and isolation. Why? We have solar that feeds the house, grid, and batteries with whole house backup.

The whole setup met code when installed, but we have more than a few labels on the panels to help firefighters know what needs to be shutdown. Could it have been done differently? Possibly. California requires metered main panel enclosures, at least around here, or we could have fed the first of the two downstream panels from the meter. However, there are no complaints from me. It works, it meets code, and it is a big step up on the original panel that was rusting and corroding. Along the way, the entire service drop got replaced when the utility got a good look at it, during the service drop replacement at the house, so I am happy.

All the best,

Peter

 

[90cummins]

Is it permissible to load a 20 amp three phase 208 volt breaker unevenly?
The table saw motor draws approximately 8 amps per phase and I want to mount a 1hp 230 volt single phase power feed on table saw and pull power from the same circuit.
Basically phase 1&2 would be loaded to perhaps 15 amps with phase 3 at 8 amps.
Will this unbalance affect the breaker.
When I go outside my comfort zone the knowledge base here at TBN never fails to impress me.
90cummins

 

[ponytug]

Is it permissible to load a 20 amp three phase 208 volt breaker unevenly?
The table saw motor draws approximately 8 amps per phase and I want to mount a 1hp 230 volt single phase power feed on table saw and pull power from the same circuit.
Basically phase 1&2 would be loaded to perhaps 15 amps with phase 3 at 8 amps.
Will this unbalance affect the breaker.
When I go outside my comfort zone the knowledge base here at TBN never fails to impress me.
90cummins

That sounds like quite the setup! (Photos?) Yes, it is done, often for the sort of thing that you want to do.

Not a direct issue for the larger breaker, but it is generally prudent to put in place circuit breakers/fusing for motors at their rated draw to protect the motors. One thing to bear in mind with motors, and saws especially is the large starting currents. So, I would recommend slow blow fuses, or breakers to prevent nuisance trips. Three phase motors are less of an issue than normal 120/240.

I have seen small subpanels used to land the various breakers, but small three phase panels can be harder to find. How far away is the shop panel? I would not mount a subpanel on the saw for dust explosion reasons.

All the best,

Peter