opinion wanted

[petersonra]

A customer wants us to supply a small control station to control some motorized valves. The valve motors are 120V and probably in the 1/8 HP range, or smaller.

Can we use the switch contacts from an AB 800T selector switch to directly control the motors? The standard switch contacts from these selector switches are not HP rated. However, AB does have some contact blocks available that are HP rated.

If we add the padlocking attachment to the selector switch in such an arrangement is it sufficient to serve as the motor disconnecting means if we were to make it a 3 position selector (open-off-close) where it could be padlocked in the off position.

Would this arrangement suffice if the panel had to be UL listed?

 

[don_resqcapt19]

I think you can use the HP rated contacts to control the motor and provided the required means of disconnect. I don't see any code issues.

 

[Smart $]

...

Would this arrangement suffice if the panel had to be UL listed?

If you are fabricating the control station, it will not be UL Listed... even if it is assembled with all UL listed parts.

 

[petersonra]

If you are fabricating the control station, it will not be UL Listed... even if it is assembled with all UL listed parts.

We are a UL shop. But, only a relatively small percentage of our work is UL. It's kind of amazing to me, but many customers will not pay the extra $25 or $50 for the sticker. Virtually everything we build could have the sticker if the customer wanted to pay for it.

 

[richwaskowitz]

We are also a UL shop and follow the UL508A standard in constructing industrial control panels. A-B 800T-XD contact blocks have published ratings: 7200 VA make and 720 VA break at 120-600 volts AC. As long as you stay within the limitations of the contact I don't see a problem. Just because you are controlling motor, this is still a control circuit and not a power circuit if that is what you are concerned about. As far as the lockable disconnect issue, I can't help you there but I am interested in what others might say.

 

[petersonra]

We are also a UL shop and follow the UL508A standard in constructing industrial control panels. A-B 800T-XD contact blocks have published ratings: 7200 VA make and 720 VA break at 120-600 volts AC. As long as you stay within the limitations of the contact I don't see a problem. Just because you are controlling motor, this is still a control circuit and not a power circuit if that is what you are concerned about. As far as the lockable disconnect issue, I can't help you there but I am interested in what others might say.

I am planning to control the FHP motor directly from the switch.