Breaker Question

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Electricalhelp

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What would be the service size for this type of breaker.

Would it be considered as a 200 AMP, 120/208V/2 Phase breaker.

I am assuming the maximum output current is 200 AMP.

Usually for three phase Voltage, I use sqrt(3)*208 = 360V

What would be the voltage measured in this case, would it only be 208V.
 

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This breaker protects either 120/240v 1ph or 120/208 1ph at 200a. You don't need a formula.
 
As Larry stated that is a two pole, 200 amp circuit breaker. Two 100 amp sections are internally connected to give you the 200 amps. Regarding your formula for 3Ø it would be 120*1.73=208 volts.
 
Electricalhelp said:
Usually for three phase Voltage, I use sqrt(3)*208 = 360V
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There isnt such a thing as "three phase voltage". Voltage is measured between two points. Typically you either measure line-line or line-neutral (to be thorough, note sometimes its a grounded conductor not a neutral, and sometimes there is neither). The 1.73 factor is that you multiply the L-N voltage by to get L-L in a wye system.
 
As noted, it's a 2-pole 200A breaker, just taking up the space of 4-poles to get the current rating. It's commonly found at the main panel of a 200A residential service, sometimes by itself ahead of the panelboard, as your example here, or sometimes attached to and back-feeding the panelboard itself, taking up the space of 4 breakers, usually right in the middle of the buss.
 
infinity said:
As Larry stated that is a two pole, 200 amp circuit breaker. Two 100 amp sections are internally connected to give you the 200 amps. Regarding your formula for 3Ø it would be 120*1.73=208 volts.
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And effectively doubling up the number of bus stabs to handle the higher current is probably at least part of the reason it is done this way.
 
MAC702 said:
As noted, it's a 2-pole 200A breaker, just taking up the space of 4-poles to get the current rating. It's commonly found at the main panel of a 200A residential service, sometimes by itself ahead of the panelboard, as your example here, or sometimes attached to and back-feeding the panelboard itself, taking up the space of 4 breakers, usually right in the middle of the buss.
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I guess, but I have never seen one deployed as a load breaker. All that I have seen have been panel main breakers. I have seen similar but smaller ones as load breakers, but usually the outer handles are tied together and so are the inner handles, but not all four.
 
ggunn said:
I guess, but I have never seen one deployed as a load breaker. All that I have seen have been panel main breakers. I have seen similar but smaller ones as load breakers, but usually the outer handles are tied together and so are the inner handles, but not all four.
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It would have to have appropriate bus connector on one end. Square D QO has 150-225 amp breakers that take up two panel spaces per pole - they just don't happen to look like four (or six) single pole units with a handle tie, wouldn't be surprised if others don't have similar though.
 
ggunn said:
I guess, but I have never seen one deployed as a load breaker. All that I have seen have been panel main breakers. I have seen similar but smaller ones as load breakers, but usually the outer handles are tied together and so are the inner handles, but not all four.
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I did not intend to imply it was a backfed load breaker. Sorry. Are you describing what I call a double tandem? Like this?

81Qcrqc8hqL._SL1500_.jpg
 
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kwired said:
It would have to have appropriate bus connector on one end. Square D QO has 150-225 amp breakers that take up two panel spaces per pole - they just don't happen to look like four (or six) single pole units with a handle tie, wouldn't be surprised if others don't have similar though.
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There may be different variants, but I’ve bought 150A QO breakers that use two spaces on each side (crossing the bus left to right) and Homeline 150A breakers that look exactly like the OP picture.


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brantmacga said:
There may be different variants, but I’ve bought 150A QO breakers that use two spaces on each side (crossing the bus left to right) and Homeline 150A breakers that look exactly like the OP picture.


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Haven't run into one for a while, but with QO version mentioned I think even though it doesn't fully cross both left and right sides of the panel, it still utilizes enough of the bus connection that you can't mount another breaker on opposite side from it.

Long ago QO had 70 or 80 amp and larger breakers that physically mounted onto both left and right side foot rails, but that design was retired by at least 1980ish maybe even closer to 1970.
 
kwired said:
Long ago QO had 70 or 80 amp and larger breakers that physically mounted onto both left and right side foot rails, but that design was retired by at least 1980ish maybe even closer to 1970.
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The 150A I mentioned mounted this way. I want to say I may have actually been a 3-pole breaker I installed in a 400A panel.


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