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Author Topic: GFCI's and LED fixtures  (Read 2283 times)

Scott Hofmann

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GFCI's and LED fixtures
« on: July 06, 2014, 04:46:35 pm »

So... about a year and a half ago I worked on an outdoor LED installation using Elation EX TriPAR's (outdoor fixture). Three fixtures to a pole. When the 120vac power was hooked up to the first two fixtures, everything was fine. Hooking up the third fixture on each pole caused the GFCI to trip. Didn't matter which order the fixtures were hooked up, it was always whatever the third one was that tripped the GFCI.
The electricians (at my suggestion), switched the circuit to a non-GFCI one and everything was fine. They eventually grounded each pole at its base. I think the problem was due to the switching power supplies in the fixtures.

So, I'm ready to spec an outdoor LED fixture install on a temporary truss structure. Given the previous issue, what would be the best approach to take on the electrical requirements? Run the concept of no GFCI and grounding the truss by the project electrical contractor?
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Scott Hofmann

Lyle Williams

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Re: GFCI's and LED fixtures
« Reply #1 on: July 06, 2014, 05:25:00 pm »

Spec a fixture without an earth leakage problem?
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Stephen Swaffer

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Re: GFCI's and LED fixtures
« Reply #2 on: July 06, 2014, 08:54:37 pm »

If I'm the contractor, I have no problem with bonding poles and truss to EGC-really should be done anyway.  GFCIs are not really required for receptacles that are not generally accessible anyway.

Bonding to the EGC should be the first line of defense anyway-but to prevent the possibility of 5 mA running through somebody than rely on a GFCI for first line defense-they are very good but they can and do fail.
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Steve Swaffer

Mike Sokol

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Re: GFCI's and LED fixtures
« Reply #3 on: July 07, 2014, 10:40:25 am »

If I'm the contractor, I have no problem with bonding poles and truss to EGC-really should be done anyway.  GFCIs are not really required for receptacles that are not generally accessible anyway.

Bonding to the EGC should be the first line of defense anyway-but to prevent the possibility of 5 mA running through somebody than rely on a GFCI for first line defense-they are very good but they can and do fail.

Bonding all light poles to the EGC is now REQUIRED by code. Last  year a dog was electrocuted in Seattle while taking a leak on a light pole. They then did an inspection of 50,000(?) light poles in the area and found 50 or so of them also showed "hot-skin" voltages on the metal pole. The original installers thought that burying a light pole in the ground or bolting them onto concrete pillars was "grounding" them. 

As we've recently been discussing, a grounding electrode by itself IS NOT A EGC (Equipment Grounding Conductor) and will not generate sufficient fault current to trip an over-current breaker.

A GFCI breaker is not required to power the light on the pole itself. However, any receptacle/outlet mounted on the exterior of the pole that the public could plug into definitely DOES require a GFCI protected outlet.
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Scott Hofmann

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Re: GFCI's and LED fixtures
« Reply #4 on: July 07, 2014, 02:40:27 pm »

Thanks to all for the insight.
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Scott Hofmann

Tim McCulloch

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Re: GFCI's and LED fixtures
« Reply #5 on: July 07, 2014, 03:53:30 pm »

Bonding all light poles to the EGC is now REQUIRED by code. Last  year a dog was electrocuted in Seattle while taking a leak on a light pole. They then did an inspection of 50,000(?) light poles in the area and found 50 or so of them also showed "hot-skin" voltages on the metal pole. The original installers thought that burying a light pole in the ground or bolting them onto concrete pillars was "grounding" them. 

As we've recently been discussing, a grounding electrode by itself IS NOT A EGC (Equipment Grounding Conductor) and will not generate sufficient fault current to trip an over-current breaker.

A GFCI breaker is not required to power the light on the pole itself. However, any receptacle/outlet mounted on the exterior of the pole that the public could plug into definitely DOES require a GFCI protected outlet.

In New York City, Con Ed is testing for voltage gradients after in incident in Chelsea several months ago.

The incident in Salina, KS (elsewhere on this forum) is not unique, it seems.  There is seldom the money to do things "right" the first time and there is never money to improve or maintain; heck it's hard to find budget for the most marginal of repairs in many cities.  I suspect we're seeing the chickens of deferred maintenance coming home to roost.  My prediction is that it will take another 20 people dying before serious measures are taken, and by then the fault mediation will be at great expense.

This comes, at least partially, from the constant Wallymartization of citizen fiscal expectations - spend less, no matter what.
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TJ (Tom) Cornish

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Re: GFCI's and LED fixtures
« Reply #6 on: July 07, 2014, 04:28:39 pm »

This comes, at least partially, from the constant Wallymartization of citizen fiscal expectations - spend less, no matter what.
I live in a suburb of 35,000 people, and we have 38 parks - one which is nearly a square mile.  We received a questionnaire a couple years ago asking about what improvements we want for existing or future parks from a proposed tax levy.  It seems to me that we get in trouble primarily by over-building in the first place - both the initial expenditure, then the obligatory maintenance in perpetuity. 

Politics aside, people should have a reasonable expectation of not dying when walking around outside.  These are tragic situations.
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John Lackner

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Re: GFCI's and LED fixtures
« Reply #7 on: July 17, 2014, 03:55:02 pm »

As strange as this may sound, it could be the power cord, with so-so wire insulation. The longer the cord, the more leakage current passing through the insulation. There also could be some inductive coupling between hot and ground through the insulation when there is increased current going through it. I had this problem once with a GFCI generator. I called the generator people and they said to try a shorter and/or different power cord. It worked.
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Re: GFCI's and LED fixtures
« Reply #7 on: July 17, 2014, 03:55:02 pm »


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