Control Circuit Only UL 508 Disconnect Switches
Control Circuit Only UL 508 Disconnect Switches
(OP)
Does a control panel with only control circuits located inside require a disconnect switch? UL508a defines a control panel as two or more control or power components.
Section 39.1 states that "a control circuit intended to be supplied from a separate source shall be provided with a disconnecting means that complies to Section 30 disconnect switches"
With that statement wouldn't any system require a disconnect switch, even simply a pushbutton box? My system has 120 or 230 Vac single phase input to a 24VDC power supply which is connected to a PLC and some control relays.
I don't see how not using a disconnect switch can be avoided
Section 39.1 states that "a control circuit intended to be supplied from a separate source shall be provided with a disconnecting means that complies to Section 30 disconnect switches"
With that statement wouldn't any system require a disconnect switch, even simply a pushbutton box? My system has 120 or 230 Vac single phase input to a 24VDC power supply which is connected to a PLC and some control relays.
I don't see how not using a disconnect switch can be avoided





RE: Control Circuit Only UL 508 Disconnect Switches
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RE: Control Circuit Only UL 508 Disconnect Switches
RE: Control Circuit Only UL 508 Disconnect Switches
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies