UL relays

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UL low voltage relevence

UL low voltage relevence

"Approval" of equipment is up to the AHJ.
The AHJ may well take into account any listing by a NRTL such as UL in determining his approval.

Revisiting this, the panel construction shall be done by a panel builder or the jobsite electrician. The sole components will be the Struthers-Dunn 450-seres 24 VAC coil, UL-relays, Square-D contactors, DIN rail, and wires. Those relays do switch line voltage.

Those relay coils are being controlled by a separate control box, one with no line voltage within it; it runs on my kind of supply voltages: 24VDC, 5VDC, and even 3.3VDC, if you count the processor buss....

Internal relays switch the external 24VAC to run the aforementioned relays in the separate box. There's an adjacent UL-labeled 2.5A float charger that will float the control box batteries.

So what if anything does UL have to do with that control box? What little I know is superficial: I always thought that if it fit under Class II (as I believe it does...), that was good enough.

One electrician says the box "Must meet UL..." but it's not clear what his basis it. The PE signing off on the project has not yet addressed this specifically, but included it in all the plans to date. (We're seeking an audience.....)

What comments do the Wise Men here have to offer?
 
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