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Author Topic: Power draw / Daisy Chaining  (Read 2077 times)

Mike Karseboom

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Re: Power draw / Daisy Chaining
« Reply #10 on: February 01, 2023, 10:35:30 AM »



In my experience with LED lighting GFCI tripping has been more of a concern rather than total amperage draw.  As already mentioned, unless you are using big power hungry fixtures, large movers, or maybe a hazer, you can typically daisy chain 8 or more and still be well under current draw / wiring capacity limits.


On the other hand, it seems each fixture and each "loop" has the potential for some miniscule, but not zero, current leakage that may affect a GFCI breaker.  Long power/dmx runs on bigger stages, cord connections on the ground, and any moisture can exacerbate the problem. 


In addition to lighting you may be energizing main speakers/amps, 4-6 powered monitors, as well as mixer, wifi, artnet converters, tablet chargers, etc from a limited number of separate outlets.  Then there is muso power for their amps, keys, laptops, phone chargers, etc. But muso/stage power always gets its own circuit in my book so any problems they introduce is isolated.


While the total current draw may be reasonable for each power outlet, and each fixture or device may be functioning properly on its own, the cumulative effect of too many devices on one circuit may be enough to trip a GFCI breaker.


I don't know the science behind this and probably could not prove anything but have had a handful of real life experiences where GFCI outlets have tripped just due to too many attached devices.  The solution has been careful re-distribution of the devices across the available outlets with attention to device count rather than current draw.  Reconfiguring wiring runs to be as short and direct as possible has also helped.


Those GFCI devices can be sensitive and  do age and become more sensitive, especially the outdoor ones. Something to keep in the back  of your  mind when wiring up a bigger show.
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--Mike
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Stephen Swaffer

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Re: Power draw / Daisy Chaining
« Reply #11 on: February 07, 2023, 12:52:51 PM »

There have been a number of discussions of GFCI functions on the Power and grounding forum.  The gist of it is is that UL allows a certain amount of leakage to ground for a device to be listed-but the total leakage to ground is the sum of the leakage of all devices in the chain.  Given that the threshold for a GFCI is only a few milliamps, it doesn't take many devices to have "acceptable" leakage to add up to a problem for a GFCI.

I would think it a good idea to test on a GFCI with maybe 50% more fixtures than you intend to use to make sure you have a bit of leakage "headroom".
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Steve Swaffer

ProSoundWeb Community

Re: Power draw / Daisy Chaining
« Reply #11 on: February 07, 2023, 12:52:51 PM »


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