Industrial Light Control Switch

[FaradayFF]

Hello,

Please help me understand something. Consider a light switch rated at 20A, 120VAC and listed for switching lighting load. Does this mean that it would be capable of "withstanding" ~ 200A of inrush current for incandescent (tungsten) or LED lamps. If my total continuous current of all the fixtures combined on the circuit is ~ 20 A, I think it is reasonable to assume that turning all the lights at once would produce an inrush of around x10 the steady-state current or close to 200Amps.

Thank you,
Sparky

 

[hbiss]

Yes, exactly. That's why it's tungsten rated. A normal switch (or contactor) is not designed to handle the high inrush current.

-Hal

 

[gar]

190207-2431 EST

FaradayFF:

See my plots P1 thru P4 at http://beta-a2.com/EE-photos.html .

Worst case peak might approach 19 times the RMS steady state value. But I would expect line impedance to limit this somewhat. If total line impedance was 0.2 ohms, and you had 15 100 W bulbs at 10 ohms each and source was 120 V, then peak inrush at 90 deg might be I = 170/(0.2+10/15) = 198 A.

.

 

[Jraef]

What is this "incandescent lighting" thing you mention? :blink:

 

[FaradayFF]

What is this "incandescent lighting" thing you mention? :blink:

Not everyone gets the benefit of working on brand new projects . Some folks work on retrofit jobs that require interfacing to existing equipment/devices that are already in place...