Trouble finding straight 240v breaker vs 120/240 breaker

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brother

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I am trying to find a 240v breaker vs 120/240 breaker for buddy of mine. This is because they are replacing a breaker for a water heater and one of the phases is the high leg delta. I suppose worse case scenerio they can go with a 277/480 rated 2 pole breaker if it can fit the panel board, am I correct on this? there is no code violation on using this correct?
 
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hillbilly1

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brother said:
I am trying to find a 240v breaker vs 120/240 breaker for buddy of mine. This is because they are replacing a breaker for a water heater and one of the phases is the high leg delta. I suppose worse case scenerio they can go with a 277/480 rated 2 pole breaker if it can fit the panel board, am I correct on this? there is no code violation on using this correct?
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Don’t know of any that will install in a 240 volt panel. Like MTW posted, use a three pole if you have the room.
 
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jap

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Someone is still going to have to explain to me why using a 240v only rated breaker is so important when in this circumstance the neutral is not even involved.

What magical event is going to happen to breech the 240v rating of a standard 120/240v breaker in this scenario?

JAP>
 
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jap

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It doesn't make sense.

Even a reading from the high leg to neutral is generally around 208 volts.

What in a 120/240v rated breaker is not rated for 240 volts as compared to a strictly 240v rated breaker?

JAP>
 
Little Bill

Little Bill

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I would guess that since the water heater's thermostat only breaks one leg. The other leg is always live, and if it happened to be the high leg that is live, then there is a potential of 208V to ground.
 
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jap

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Little Bill said:
I would guess that since the water heater's thermostat only breaks one leg. The other leg is always live, and if it happened to be the high leg that is live, then there is a potential of 208V to ground.
Click to expand...

Who cares?

Both breakers indicate they are rated at 240 volts.

What's the difference?

JAP>
 
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jap

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Which leg of a 2p 120/240v breaker is rated for only 120 volts?

I would think they are both rated for 240 volts.

JAP>
 
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jap

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hillbilly1 said:
The manufacturer can sell a more expensive breaker. Remember, most of the code is written by manufacturers. That is how arc faults came into being.
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Yes but it's being enforced.

I need to know the why.

Put in a 3p breaker or step up to a 277/480v breaker where a 2p breaker is needed just to satisfy a voltage rating that seems to already cover the voltage? Seriously?

There's got to be a better reason.

JAP>
 
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jap

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Little Bill said:
Submit a change proposal to say that 240/120V breakers can be used on a high leg system if the loads don't require a neutral.
Click to expand...

You would think somebody would of thought of that already.

Neutrals are very seldom if ever involved in a Wild Leg branch circuit.

JAP>
 
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jap

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Is there something in a 120/240v rated breaker that is less robust as compared to a 240v only rated breaker?

It has has to have something to do with the breaker itself, not the voltage it's stabbing onto.

The voltage is within the spec unless someone knows of anything a wild leg and a neutral is used to feed.

Hold it,,,,,,, I may have jus answered my own question,,,, Never seen it done, but, one could use the wild leg and a neutral to feed 120-277v lighting.

Never mInd.

JAP>
 
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jim dungar

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It has to do with the breaker's internal ability to safely clear a fault.
A fault on a 120V to ground circuit can be cleared fairly easily so the breakers can be made cheaply
As the voltage nears 240V to ground the internal arcing paths need to be changed resulting in a more expensive internal construction.
 
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jap

Senior Member
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Electrician
jim dungar said:
It has to do with the breakrrs internal ability to safely clear a fault.
A fault on a 120V to ground circuit can be cleared fairly easily so the breakers can be made cheaply
As the voltage nears 240V to ground the internal arcing paths need to be changed resulting in a more expensive internal construction.
Click to expand...

It's all starting to make sense now.

Thanks,

JAP>
 
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