Can you use a 240V breaker on a 600V system?

[thetaylorleopold]

This is hypothetical, I am just curious. Please give this some thought.

I have a 600V, 5HP motor (3728.5 Watts) and a 600V panel I want to supply it from.

If I use a 20A, 600V breaker - the breaker will see ~6A on motor run. (P/V=I , 3728.5/600 = ~6A)
If I use a 20A, 240V breaker - the breaker mechanism will act as if ~15.5A is passing through. (P/V=I , 3728.5/240 = ~15.5)

For a 20A breaker, looks like 240V would work. What am I missing here? Does voltage have any affect?

 

[pc1966]

Using any component beyond its rated capacity is a recipe for disaster!

This video shows some testing beyond rating for some breakers and fuses. Yes, the energy levels are above domestic but the less is clear:

 

[Lucien Nunes]

The voltage rating of the breaker is the maximum that it can handle and needs to be equal to, or greater than, the voltage on which it is used. It has no effect on the voltage or current of the motor.

 

[James]

This is hypothetical, I am just curious. Please give this some thought.

I have a 600V, 5HP motor (3728.5 Watts) and a 600V panel I want to supply it from.

If I use a 20A, 600V breaker - the breaker will see ~6A on motor run. (P/V=I , 3728.5/600 = ~6A)
If I use a 20A, 240V breaker - the breaker mechanism will act as if ~15.5A is passing through. (P/V=I , 3728.5/240 = ~15.5)

For a 20A breaker, looks like 240V would work. What am I missing here? Does voltage have any affect?

Your maths is wrong.
No matter what the rating of the breaker, the voltage applied is the same, you said 600v.
Unless you are using a transformer to reduce or increase the voltage.

 

[thetaylorleopold]

Using any component beyond its rated capacity is a recipe for disaster!

This video shows some testing beyond rating for some breakers and fuses. Yes, the energy levels are above domestic but the less is clear:

Thanks for the reply. I am trying to understand why it is a recipe for disaster. The current will be the same no matter which breaker i use. If the breaker is rated for the right amperage, why does voltage matter?

 

[DPG]

Thanks for the reply. I am trying to understand why it is a recipe for disaster. The current will be the same no matter which breaker i use. If the breaker is rated for the right amperage, why does voltage matter?

The device has a maximum working voltage as this is what it has been designed, built and tested to. Also any clearances etc between the contacts will not be suitable for a higher voltage.

You really don't want to be doing this, as it will be dangerous not just for you, but anyone following.

If you want a good example, try powering an electrolytic capacitor at double its rated maximum voltage. With goggles on.

 

[Lucien Nunes]

All electrical switchgear has a maximum voltage rating just as all pipes have a maximum pressure. On a switch or breaker it's especially important because when the contacts open, the voltage appears across them. The higher the voltage, the more difficult it is to extinguish the arc, and the more power dissipated in the arc while it continues.

 

[thetaylorleopold]

Thanks everyone. I know it is kind of a silly question but I appreciate the answers.

 

[telectrix]

the simple answer to the original question is ... Yes if you want to see a nice Bang. try applying 240V to a 110V light bulb.