208 high leg rated breaker

[Chuck609]

Is there any thing in the code book about using 208, bolt in, rated breakers on an high leg. I understand the 120/ 240 volt, 277/ 480 volt breaker rating. But is there a rating difference between 120/ 240 snap in and a 208 bolt in?
Thanks

 

[don_resqcapt19]

I have never seen a breaker with a 208 volt rating. The breaker used on the high leg must be a straight 240 volt rated breaker. Not a slash 120/240 volt rated breaker.

 

[big john]

...But is there a rating difference between 120/ 240 snap in and a 208 bolt in?
Thanks

Yes. A 120/240 volt breaker can open up a 240V fault when when the circuit is connected across both breaker poles. Each pole inserts an air gap so it makes it harder for an arc to sustain itself and reduces the damage to the breaker.

A straight 240V breaker must be able to open a 240V fault with a single pole of the breaker. There's more energy that is available at a single air-gap so there's more risk of damage to the breaker.

 

[tom baker]

And FYI, a 240 volt rated breaker is more expensive and some wholesale houses won't stock.
One advantage of a bolt on breaker is for backing feeding as a main, don't need the retainer.

 

[norcal]

And FYI, a 240 volt rated breaker is more expensive and some wholesale houses won't stock.
One advantage of a bolt on breaker is for backing feeding as a main, don't need the retainer.

This! Plus older (built before the retainer requirements) plug in panels will not accept retainer / hold down kits for backfed breakers.

 

[ActionDave]

This! Plus older (built before the retainer requirements) plug in panels will not accept retainer / hold down kits for backfed breakers.

How do you use a use a bolt on breaker to backfeed a plug in panel?

 

[ActionDave]

And FYI, a 240 volt rated breaker is more expensive and some wholesale houses won't stock......

True. I have found it easier to get, and cheaper to buy, a three pole breaker and just use two poles of the three available.

 

[iwire]

How do you use a use a bolt on breaker to backfeed a plug in panel?

TEK screws.

 

[norcal]

How do you use a use a bolt on breaker to backfeed a plug in panel?

It did not come out as intended, :happysad: we all know you can't but there has to be someone who tried the TEK screw method, I'll pass on that idea, though.

 

[FREEBALL]

If your talking QO or another 120/240 rated panel that was used way back when with a 240/120 Delta your not going to find anything rated for that single high phase but if its an Iline Square D this is an option.

 

[jim dungar]

If your talking QO or another 120/240 rated panel that was used way back when with a 240/120 Delta ...

The no-longer-legal 'delta' breakers had to do with providing a 3-pole breaker in a single phase panel. The 208V high leg issue is about going from a 3-phase panel to a 1-pole breaker.