4 pole 240 V breaker

[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