Double throw switch for elevator

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electrofelon

electrofelon

Senior Member
Location
Cherry Valley NY, Seattle, WA
We have an elevator that we don't really want to have full time on a generator circuit because it chews up a lot of it's capacity. I was thinking about providing the supply with a 3PDT switch so we could throw it over to backup power in case someone gets stuck in the elevator. I know elevators are super rules-ee, are there any issues with this plan?
 
I don't know about elevator rules, but you are talking about using a proper manual transfer switch and not some other type of switch right?
 
Some double throw switches aren’t rated for load make or break.

So it would be better to use a manual transfer switch.
 
steve66 said:
Some double throw switches aren’t rated for load make or break.

So it would be better to use a manual transfer switch.
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I'm hoping he's talking about a ON-OFF-ON safety switch. You can't use any random ON-ON two position switch to transfer between two sources.
 
Why don't you just throw the fire department override, that will bring it down to floor 1 and block any other use (without the key).
 
wwhitney said:
Risk of simultaneously connecting to both sources if there isn't a defined "off" position between them.

Cheers, Wayne
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Okay well of course...... I'm not sure there is such a thing as a make before break double throw switch except custom-made or for specialty applications. I guess I figured it would be obvious to make sure one did not have such a switch if picking one at "random".
 
electrofelon said:
Okay well of course...... I'm not sure there is such a thing as a make before break double throw switch except custom-made or for specialty applications. I guess I figured it would be obvious to make sure one did not have such a switch if picking one at "random".
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Right, but the question is whether a random on-on double throw switch is guaranteed to never make before break. Or rather, to have no switch position in which both sources could simultaneously arc to the switch. So I think the comment was that you want a product that is designed with that guarantee in mind, e.g. an on-off-on switch.

Cheers, Wayne
 
wwhitney said:
Right, but the question is whether a random on-on double throw switch is guaranteed to never make before break. Or rather, to have no switch position in which both sources could simultaneously arc to the switch. So I think the comment was that you want a product that is designed with that guarantee in mind, e.g. an on-off-on switch.

Cheers, Wayne
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Okay sure well it's pretty much a moot point anyway as I believe all the manufacturers switches have an off. I just looked at the siemens catalog and that is all they offer.
 
wwhitney said:
Risk of simultaneously connecting to both sources if there isn't a defined "off" position between them.

Cheers, Wayne
Click to expand...
This is typically a problem when using 'wall' style switches, which do not have internal room the required line to line insulation. Most 'safety' switch style devices do not have this issue.
 
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