…No beep…OL
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I put the periods because I have to have at least 20 characters to place a comment
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Ok, that is good. This means that neutral is not shorted to the ground anywhere in the fixture or your wiring. This would have caused a full 120v on the case of your fixture when it was back-fed from an improperly wired outlet.
The electronics inside the fixture are not simple, it is possible for the fixture, when energized backwards, to leak some current to the ground still, but this is not simple to test. Nor is it safe to replicate your initial condition to try and figure out exactly how much potential there was on an ungrounded case.
Next step would be to repeat the last step, with the timer on, but measure continuity between the hot and the ground. You should get OL still. With a normal incandeacent bulb uou would get a resistance value, but with a driver you should get an open loop. We are testing for ground faults, not the internals of the driver
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Thanks @HappyHemper but I have to set everything down an help my wife out before I do anything else.
If I don’t listen then no mo 
. I’ll try to come back an test some more but thanks for your help
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You are most welcome @AlwaysLearnin.
Assuming the last test work the way it should, It looks like 3 things were happening:
- Outlet does not have a ground.
- Outlet had hot/neutral reversed
- Timer does not switch the neutral
As a result, a fixture fed with wrong polarity partially energized the case during “lights out” (due to internal fixture design), and since there was no grounding at the outlet, the potential was not dissipated.
If you have a properly wired, properly grounded outlet, I believe your fixture and timer will work properly. Functional grounds are super important. To a fault perhaps. If you had a functional ground in that outlet, you might not have even discovered that there is reversed polarity on the receptacle.
Have a good one,
HH
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Seems like you are solving this issue. Good work guys, I love to see this kind of teamwork.
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Thorough job. Good work, gentlemen. Mirroring what ReikoX says, it’s this kind of teamwork that makes OG such a great place!
Also, once you guys get the lamp back into service, please remember to measure the AC voltage potential between the chassis (several locations) and the ground for sanity purposes. Should be no greater than 30VAC, ideally much less.
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OK folks, I am an electrician and the receptacle in question that was wired reverse polarity did NOT cause the shock he got from the light chassis.
Also when he rewired the receptacle properly the plug tester confirmed everything was OK and grounded properly, he said he was reading open ground on some other receptacles in the house.
@ AlwaysLearnin,
Is it relatively easy to open that fixture and have a look inside, especially the line side of the driver?
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There is no dead short or ground fault, true, however the driver inside may in fact misbehave if neutral is energized, but hot disconnected. It may try to pull reference from the ground.
I guess my point is that IF there was a functional ground in the outlet, having tested and confirmed the path from the case to the ground pin at the end of the extension cord, there would have been no way for the OP to feel any shock from said case.
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The ONLY way to diagnose the shock knowing the receptacle is properly wired is to open the fixture, it’s likely the neutral is grounded somewhere inside.
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You are correct @wolfedawwg.
I’ll be able to tell you for sure when I get home from work today but from what I remember seeing on the fixture when testing yesterday, there were 4 Phillip screws on the sides.
By testing continuity between the ground pin and the neutral blade on the cord end, you will be able to tell if neutral is bonded to the ground inside the fixture. If this test shows an open loop, when the fixture is open, ideally one would see the service ground wire bonded to the case, the hot and neutral spliced into their respective counterparts on the driver. Maybe with a cheap switch inline on the hot.
The problem with electronic drivers is that their components reference the neutral. EMI filters, diode bridge rectifiers, power factor correction circuitry, and dc-dc converters are all ICs in the driver, which have transistors, diodes and other fun stuff. Secondary ground may be created after the second, DC rectifier.
If you were to put power down to the neutral, as was the case, and float the wire that is supposed to be hot, which was the case, do we know how all the circuitry inside this particular driver would react? I do not. Is it possible that it would leak to the ground? Absolutely. Should proper case grounding take care of such leak? Yes! I mean, you have a wire with almost no resistance going straight into dirt. There is no way anyone would feel a light potential on the case if the grounding is proper.
In fact, we do not even know what the potential of the zap was, what the frequency was (before the high-frequency switch, or after?), we do not even know if it was AC, DC.
Is it safe to replicate the condition to find out? Not really. Not without a scope, a bench, and some knowledge of electronics.
In summary, it is my humble opinion that unless there is a G-N bond inside the fixture identifiable by testing continuity on the cord end, there is no point in taking apart the fixture to look for a G-N bond.
But i did it anyways. Here’s what’s inside. No G-N bond is possible without also being identifiable at the cord end. Ground hits a fan standoff right away, immediately bonding it to the case; and neutral is isolated and carried to the drivers, where it terminates. Drivers are isolated. Any short would be visible at the cord end.
I still believe the current leak was an artifact of reversed polarity, combined with a floating of a, now backwards, reference. And due to a missing ground connection, the effect was felt. Having tested the wiring, and corrected the receptacle, it should be safe to put the fixture back in service.
Cheers,
HH
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Additional note on this discussion, just because there is a safety ground does not mean the chassis as a whole has a low impedance path to the ground across the entire chassis. Hence, you could have a perfectly good earth ground into the unit but yet could still see AC when something has gone awry allowing AC components on the chassis (reversed line / leakage or otherwise).
Thank for opening a unit up. This design has what amounts to wall worts as the internal supplies (which says things in my mind). This is where electrical design and design for manufacturing practices can come into play. How much paint splatter is there during manufacturing, the torque of the screws on the chassis, return paths, etc, etc can have an effect on the safety return. No kidding.
One question I have, looking at the photo, it appears the safety is tied to a grounding standoff backed by plastic at the fan. A source of vibration. Could this become loose? It probably wouldn’t hurt to ensure the fasteners are torqued sufficiently.
Also, I wonder if this unit has any compliance certifications?
Other than that, I think you guys are getting close to a resolution.
Edit: It probably wouldn’t hurt to open up the unit in question for look-see, some of the wire routing looks as though they could contact sharp surfaces.
Edit, edit: @HappyHemper, can you tell where the DC ground point is for all these supplies? At the PCB on the other chassis half? I can’t tell from the photo.
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Very very good point.
I have two of these units. Both look identical to the OP’s King Plus 1000 (down to stamped metal grates for ventilation and PCB layout of diodes). Probably made at the same factory on a different shift.
One unit is c/w 3x 60W drivers for a total of 180W of light output, and a 1A@12VDC for the fans.
CE/ROHS on both. No UL/cUL on either
Second unit only has 2x 60W drivers.
Now in terms of the DC…
Both units have power and common coming from the driver to the PCB, isolated
However, the 120W unit also has the PCB bound to the chassis via standoff screws. Not sure if this is intentional or not…
The 180W unit has isolators on the standoffs, and is dabbed with silicone all the way around, so no path to chassis from the PCB.
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I didn’t say the ground and neutral were bonded, I stated a neutral may be grounded somewhere inside, and by that I meant accidentally.
I see from the pic there are lots of pinch points from screws and such. Also could be bad or nick in insulation.
The measurement performed earlier with the DMM from neutral to ground is simply checking for continuity, not current leakage.
To test current leakage you need a megger.
If you don’t have a megger the only other tool is your eyes.
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sticking timers are known fire hazards
Just get a new one. please
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Got it. Leakage current. Insulation issues etc. Only evident under load in that neutral.
Yes, possible. Totally thought you were referring to a solid bond. I blame beer, flowers, and ESL. Good point.
If i have some time later today I will miswire both of mine and see how much the chassis leaks, with either bonded or unbonded PCB
By design, filters in the power supplies leak pretty much always. IEC spec is 3.5mA in class 1 equipment. 0.25mA in class 2. Should be easily taken care of by even a high-ish-impedance ground. But since these are not grounded, it would leak into the neutral. So no, not that.
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@HappyHemper
lol
I prob could have explained better as well.
I blame the beer and other things… but never the flower…lol
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so the only other way for me to test it out is to plug it in an check to see if it turns completely off? But then again I won’t be using the same timer. I have a new timer