Low Voltage on Starter Aux Contact

[xguard]

I have a Trane chiller. It has an external (customer supplied) low voltage circuit for a flow switch and motor starter auxiliary contact. So if the pump isn't running (no flow or pump starter not energized) the chiller is prevented from running.

These low voltage wires enter the combination motor starter disconnect, and land on the auxiliary contact. The coil voltage on the starter is 120 VAC, the pump voltage is 240 VAC. Is this low voltage circuit allowed to be in the same enclosure as the 120 VAC and 240 VAC circuits. I recall there are separation requirements in conduit but I didn't understand how that worked out when they are needed to be connected to the same device.

I realize there are different types of low voltage circuits, from the ancient trane literature and wiring diagrams it appears to be 24 VDC. It's not clear if it's class 2 or not.

 

[petersonra]

I have a Trane chiller. It has an external (customer supplied) low voltage circuit for a flow switch and motor starter auxiliary contact. So if the pump isn't running (no flow or pump starter not energized) the chiller is prevented from running.

These low voltage wires enter the combination motor starter disconnect, and land on the auxiliary contact. The coil voltage on the starter is 120 VAC, the pump voltage is 240 VAC. Is this low voltage circuit allowed to be in the same enclosure as the 120 VAC and 240 VAC circuits. I recall there are separation requirements in conduit but I didn't understand how that worked out when they are needed to be connected to the same device.

I realize there are different types of low voltage circuits, from the ancient trane literature and wiring diagrams it appears to be 24 VDC. It's not clear if it's class 2 or not.

It does not matter much what voltage it is. Class 1 circuits can be any voltage up to 600 V AC or DC. In any case, most control circuits of this type are class 1 circuits. Class 1 circuits don't have a whole lot of restrictions on where they can be as far as being with branch circuits they are associated with.

It's only class 2 if it follows all the rules for class 2 circuits. There is some provision for terminating class 2 conductors in the manner you mentioned as long as you follow the rules in article 725 for doing so.