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crunch time, GFI and fluorescent light compatability troubles

K

Kevin Q

Aluminum
Joined
Mar 26, 2006
Location
Wyoming
I am in the process of installing lights in an enclosed 12' utility trailer. I will be traveling to various venues sharpening knives. The power at these venues is outdoors, like an RV campground, accessed via a cord and a breaker panel inside the trailer with strip receptacles. Each light plugs into the strip receptacle and then goes to a switch. This is so I can turn each light on independently. I may have sun shining in one end of the trailer and not need the light on that end, for instance.

I wired in the first light this evening and flipped the switch and got a flash of light and a tripped GFI. Checked all connections and no luck. 1 light on the circuit, #12 wire in the extension cord, 4' 2-bulb light. High intensity ballast and T-8 bulbs. Not a cheap shop light, $80 ea. I have the light on a non-GFI circuit and it works fine. However, I am afraid that the areas where I park the trailer are all going to have GFI breakers because their power is on a pole outside for the vendors. Is there a work around for this problem? I know that this isn't a machine question but I also know the experience here is multi-talented.

Thanks in advance, KQ
 
Your problem is not in the components. You need to recheck your wiring. if you have a wire backwards it will trip the gfi.

Slightly ot funny, a guy gave me a 220 volt grill because he kept getting shocked by it. I looked at the plug and he wired the common into the ground so the current was running through the grill before it grounded out. So every time he touched it he got bit.
 
Had an electrician look at the wiring, took everything apart and retightened wire nuts, etc. I had been running hand tools all day on the same GFI and had no problems. And light does fine on a non-GFI outlet. Still flummoxed.
 
Kevin Q said:
Had an electrician look at the wiring, took everything apart and retightened wire nuts, etc. I had been running hand tools all day on the same GFI and had no problems. And light does fine on a non-GFI outlet. Still flummoxed.
Click to expand...

So if the gfi works it is between the gfi and the fixture.

Did the electrician do that work?

Do not assume the electrician was of sound mind. I have seen an electrician almost blow him self up on a service disconnect because he was hung over.

I am typing this fast because don trims the heard quick on meaningless topic titles. . . Gotta make the title searchable.
 
It likely trips the GFCI because the CFL (and many LED) lights produce a lot of EMI (electrical noise) which can confuse the GFCI circuits.

It's a known problem.

It is possible that installing a noise filter in the lighting circuit will fix the issue.. Also I believe the GFCI for the RV outlet, if there is one, may be less sensitive so it causes less trouble. But don't count on that.
 
A second on JST's observation. Problems with electronic ballasts in flourescent light fixtures causing nuisance tripping of GFCI's are not uncommon. And the high intensity ballast the OP mentioned could possibly exacerbate the issue.

There are special GFCI's available that are engineered to prevent nuisance tripping, but I doubt that would be a viable solution to Kevin Q's problem since he will be relying on power from a GFCI protected source that is not under his control. JST's observation that the "RV" power source might possibly be less sensitive to nuisance tripping may have some merit. Is there one of the venues nearby where you could access the site power source for a temporary test of the light fixture(s) in question?

FYI, here's a link to a product line of specialty GFCI breakers that includes some good information on the general subject of nuisance tripping. Chapter four contains information specific to lighting applications:

http://www.engineering.schneider-el...n_against_nuisance_tripping_voltage_surge.pdf

~TW~
 
IMHO just get a diffrent lighting fiture. I have installed hundreds of HF ballested of all makes over here in EU land and never a issue. Mind you over here we don't use wire nuts and have some regs that state just how cleanly the lighting must use its electric.
 
The EU and US GFCI are not equivalent.

A standard US GFCI for residential use trips at 5mA of leakage. An EU type typically does not trip until 6x higher current, 30 mA (thi is mentioned in the Schneider paper linked above).

While neither type is an absolute precaution against electrocution, the US type will normally avoid severe shocks, with the price paid being higher sensitivity and more nuisance tripping.

The Schneider better types include filtering for EMI, and there is no reason why that cannot be simply added to the lighting circuit. All the filters are UL recognized, so they can be simply put in a suitable box in-line with the lights.
 
As Jerry said in his preceding posts.

This is the same reason why you can't run a vfd from a typical gfci. The "noise" is dumped to ground via the input filters and is seen as a current imbalance.
 
You may have leakage current in the bsllast.

Simple test...dis-mount the ballast so it cannot touch ground and retest.

If it works then leakage is the problem.

Lighting is not usually connected to gfi so it is not considered in design.

So if works then mount ballast with grommets and be good.
 
By design you do have leakage current inside the ballast. Do no remove the ground from the ballast; for safety it is supposed to be grounded. The leakage will raise the potential (voltage) on the ungrounded case and you become the path to ground.

The problem is the current to ground that happens inside of the electronic ballast at the bare-bones internal power-line filter - to meet FCC rules and rarely more than an in-line inductance and a couple of small capacitors across the power feed and to ground. External cores and other filters are ineffective in this case - the GFCI is looking for current imbalance in the power feed, and by "noise current" to ground that's what you get. An isolation transformer just for the lights (over-rate it and make sure it can cool) will "solve" the problem of an external gfci tripping, or, find another ballast type that works with a low trip gfci.
 
Lakeside53 said:
These are not magnetic ballasts.
Click to expand...

I came back to this thread after thinking about the fact that breakers trip due to heat because it is magnetic . I want to learn more on the matter.

A gfi does employ a simple magnetic breaker right? it, gets hot and . . . pop.

Can someone give me some credible reading material on the issue? Thanks in advance.
 
I suggested mounting ballast with grommets.

The case or fixture needs to be grounded.

If the ballast is where it cannot be touched then not being grounded will cause no danger.

You can do this to your lights but not comeone elses...

Other option is to use the 30 amp or 50 amp connections at the rv place as they are usually not on gfi.

Most rv places sell adaptors from anything to anything else so you coukd fo that and avoid the gfi.
 
Thanks a bunch for all the help. As I already knew, there is a lot of knowledge here on this site, not just with machine work. I do appreciate all the suggestions. Most places I will be plugging into 30 amp services like a normal RV park does so perhaps I am worried about something that is more easily dealt with. I had thought those services were GFCI protected but apparently not. That will help. In the meantime I will look for an isolation transformer. Thanks, KQ
 
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