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GFCI Theory

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Mike Sokol:
Here's an update on an industrial 3-phase GFCI with variable threshold settings. http://tinyurl.com/o29zt8u

As you can see, it's a 3-phase unit with up to 100 Amp capability. From a quick read it appears to be for line-to-line loads only (motors and heaters?), not for line-to-neutral loads as we would normally use to power our amps and stage gear. And it's selectable for 6, 10, 20 and 30 mA trip points, but not while in GFCI mode since that's a code violation, or something to that effect. Should be an interesting read though.

I'm guessing that at some future point the lighting industry will probably require this sort of thing, but I don't believe that's of immediate concern. But it's always good to look ahead a little to see what's coming down the pike...

Jeff Robinson:

--- Quote from: Mike Sokol on September 26, 2013, 02:36:45 PM ---Here's an update on an industrial 3-phase GFCI with variable threshold settings. http://tinyurl.com/o29zt8u

As you can see, it's a 3-phase unit with up to 100 Amp capability. From a quick read it appears to be for line-to-line loads only (motors and heaters?), not for line-to-neutral loads as we would normally use to power our amps and stage gear. And it's selectable for 6, 10, 20 and 30 mA trip points, but not while in GFCI mode since that's a code violation, or something to that effect. Should be an interesting read though.

I'm guessing that at some future point the lighting industry will probably require this sort of thing, but I don't believe that's of immediate concern. But it's always good to look ahead a little to see what's coming down the pike...

--- End quote ---

http://www.trci.net/products/hd-pro/6-10-30-60a-80a

A company that's been doing it for 30 years. Founded to build military genset controls.

There are applications at 480 (+) volts that can establish arcs that do not grow large enough to trip OCD's. Also required for all (un-shielded) pipe heat tracing (30mA is standard for this).

5mA trip level is required to be called GFCI for people protection. ELCI is for equipment protection.

Many industrial UL489 breakers offer a ground fault option (the G in LSIG).

Full disclosure: I've sold their devices a few times in the last 15 years.

HTH,

Jeff Robinson

Canute J. Chiverton:
Is it true that the inline GFCI sometimes falsely trip and therefore can shut off power?  Is this a regular occurrence?

David J. Thomas:
Effectively they work the same way.  They both sense unwanted current to ground and shut power off, however, a GFCI (by commonly accepted US standards) must shut power off when it senses current leakage of 6mA maximum, whereas an ELCI can be set to shut off power at almost any current leakage level.

John Chiara:

--- Quote from: Mike Sokol on September 25, 2013, 08:18:00 AM ---I would agree. In a few industry articles I've read, there hasn't been a single documented case of an AFCI actually preventing an electrical fire. The electrical fire started anyways, or the AFCI tripped so often with things like AC/DC motor loads that it was removed. Seems like a good idea that was poorly implemented.

On the other hand, GFCI breakers really do save lives, as long as they're installed properly. A young girl was electrocuted last year at an Orlando miniature golf water feature. The police report stated there were GFCI breakers feeding the fountain pump, but somehow they were installed improperly so they didn't trip.

I've not played with this on the bench, but I'm pretty sure there's a way to improperly install a GFCI breaker so that it will test as OK using the built-in TEST button, but not actually be able to disconnect the circuit during an electrocution incident. More to study on that aspect of GFCIs.

--- End quote ---

That girl was a friend of mine's neice. Still waiting on the lawsuit on that one.

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