Snap switch vs switch?

[PillarOfAutumn]

I’m looking at disconnecting means in article 430.109 (C) 1 & 2

(1) References a “general use switch”.
(2) References a “general use snap switch”.

I always thought a snap switch was just a regular toggle switch. Is that correct? And what is the difference between the two?

 

[jap]

I may be wrong, but, I think a "snap" switch is a regular toggle switch that goes "snap !!!!" when it opens and closes.

JAP>

 

[suemarkp]

You need to read more of the words in 430.109(C)(2). It says "a general-use snap switch suitable only for use on ac (not general-use ac–dc snap switches)".

These are your normal wall switches and they have an "AC Only" marking on their face. They tend to be silent as you move the switch. The older AC/DC toggle switches make a loud click or snap when you move them (my Grandma's house switches sounded like that). Those are what are referenced in part (1).

What I don't understand in this section is why the limit is 2HP. A 240V motor will draw half the current of a 120V motor if the horse power is the same. Would think a 20A switch is a 20A switch whether the voltage is 120, 240, or 277, so a higher horsepower limit should be allowed for motors at the higher voltage range. You'll never need a switch over a 15A rating for a 240V motor with the limitations imposed.

 

[synchro]

What I don't understand in this section is why the limit is 2HP. A 240V motor will draw half the current of a 120V motor if the horse power is the same. Would think a 20A switch is a 20A switch whether the voltage is 120, 240, or 277, so a higher horsepower limit should be allowed for motors at the higher voltage range. You'll never need a switch over a 15A rating for a 240V motor with the limitations imposed.

Perhaps the horsepower rating is due to a maximum energy limit (i.e., heat) that's allowed in the arc that happens when the switch interrupts a motor load? In that case the voltage x current, and not just the current, could be a limiting factor.
I agree that the current capability of switch contacts themselves would be independent of the voltage that's applied to a load when the contacts are closed.