EQUIPMENT DISCONNECT

[fifty60]

I am trying to determine whether or not I can use a UL508 Motor disconnect switch as a line of sight disconnect switch on my equipment. The switch has the correct IEC ratings for me to do just that in Europe (IEC-947-1 and IEC-947-3). But for the US, it is only UL-508 listed.

The UL-508 switch is marked "Suitable as Motor Disconnect", so It may work under NEC 430.109 (A)(6). My equipment has a combination of heaters, compressors, and an isolation transformer for control circuitry.

Would using the UL-508 listed switch imply that the end user would have to supply the UL-98 service disconnect? Can I only use the UL-508 listed switch internal of the equipment downstream of a UL-98 or UL489 listed component?

These smaller disconnect switches are used a lot in Europe, but I am not sure if the UL-508 listing forbids me from using it here in the States as a line of sight disconnect for my equipment.

 

[Jraef]

I am trying to determine whether or not I can use a UL508 Motor disconnect switch as a line of sight disconnect switch on my equipment. The switch has the correct IEC ratings for me to do just that in Europe (IEC-947-1 and IEC-947-3). But for the US, it is only UL-508 listed.

The UL-508 switch is marked "Suitable as Motor Disconnect", so It may work under NEC 430.109 (A)(6). My equipment has a combination of heaters, compressors, and an isolation transformer for control circuitry.

Would using the UL-508 listed switch imply that the end user would have to supply the UL-98 service disconnect? Can I only use the UL-508 listed switch internal of the equipment downstream of a UL-98 or UL489 listed component?

These smaller disconnect switches are used a lot in Europe, but I am not sure if the UL-508 listing forbids me from using it here in the States as a line of sight disconnect for my equipment.

It can be the line-of-site disconnect, it just cannot be the ONLY disconnect in the circuit, because it cannot be the motor BRANCH circuit disconnect. For that you must have a UL98 or UL489 listed device. So if you have a motor starter up stream than has a CB (UL489 listed) or FDS (UL98 listed) in it, you are fine. If you are trying to USE this as the motor branch circuit disconnect, you cannot.

 

[fifty60]

I would like to use the switch as a means for disconnecting my equipment from the electrical supply. Every branch inside of the equipment has a UL489 circuit breaker. Their would have to be a UL 98 disconnect separate from the equipment, at the beginning of the feeder circuit.

If there is a UL 98 disconnect external to the equipment upstream from the UL 489 switch, and UL 489 breakers downstream of the UL 489 switch, would I be able to use the UL 489 switch? The equipment has heaters, compressors, and an isolation transformer for a control circuit. All of these branch circuit are protected by UL 489 breakers.

I've found mixed answers so far. Some information leads me to believe that if the load has anything more than motors, and the UL 489 switch indicates "Suitable for Motor Disconnect", that you have to use the switch only for motor loads. I want to use the UL 489 listed switch marked "Suitable for Motor Disconnect" as the means for disconnecting my equipment from the electrical supply for servicing.

There would not be a motor controller upstream, but there would be a feeder disconnect upstream.