Electrical Help

[ScottyMo]

Looking for some help from any electrical gurus.

Here is what I have been running…

2 singing faces: Each contains a 27 channel 12v DC controller and a 16.5amp power supply.

Scale model: Contains 8 27 channel 12v DC controllers and 2 16.5amp power supplies.

Load is minimal because it is only the scale model. (About 2 and half strips of 30leds\m.)

I have been running all of my testing for months with no issues. All running from a standard outlet.

Over the weekend, I did the electrical prep work for my full scale show. I ran 2 dedicated circuits from the panel to the garage. I installed a GFCI receptacle for each circuit. I then plugged my faces and model into one of the new receptacles. However, the GFCI keeps tripping.

I spent a lot of time last night troubleshooting and double checking everything. At the end of all that, I found the problem to be the ground wires to the power supplies. If I disconnect the ground wire from all of the power supplies, and just use hot and neutral, I have NO problems. If I have the ground connected to just one of the four power supplies, I have NO problem.

However, as soon as I have MORE than one power supply with the ground connected, I start tripping the GFCI.

The power cords I am using to feed the power supply are standard 3 pronged computer power cables. They are wired the same to each PS. Brown (hot), Blue(neutral) , Green(ground).

Am I missing something? Is this normal? Should I not be connecting the ground to the power supplies?

Thanks in advance

ScottyMo

[MtDew4me]

I am having no issues in hooking up multiple 27-channels controller boxes (each with their own independent "350W Dual Output Switching Power Supply;88 ~ 264VAC input;12V/350W output, CE and ROHS approved" purchased from Ray Wu) to the same GFC outlet.

Make sure you also independently test each extension cord used between the GFCs and the controllers. I was popping a GFC outlet last year and it turned to be one of the extension cords.

Good luck,

Brandon

[viennaxmas]

I am wondering if there is a ground loop on the low voltage side. I have seen some strange ground issues with some of the low voltage equipment (which in the end blew up my DMX Interface). If you have an ohm meter you may want to check if there is any connection between the low voltage ground (e.g. the DMX ground) and the electrical ground. Tripping can also be caused by the "Dual Circuit" situation you have, assuming there is some low voltage ground connected to the main ground, you could potentially create a perfect ground loop between the two GFCI..It might be worth getting an electrically insulated DMX splitter and run each output to one of the boxes you have...

[ScottyMo]

Thanks for the replies thus far.

This one is driving me crazy. It does not appear to be a bad wire anywhere. I have tried different extension cords. Different GFCI's. Different controllers. Different power supplies. And different light strips. I even tried both my Entec Pro and Entec Open DMX dongles. I've taken my singing faces, and my scale model out of the mix. I can re-create the problem on-demand with just 2 controllers and 2 power supplies. Each controller has only 1 8' led strip attached to it.

The one interesting thing I found when testing this minimal setup is that it only trips when I use white. (all three colors)

My setup is this...

15 amp breaker from the panel to the GFCI receptical. 25' extension cord to the control boxes. Each control box has 1 16.5amp 12v power supply, feeding a 27 channel DMX controller. Only 1 led strip is hung off the controller.

If I connect the ground wire on only 1 or none of the power supplies, there is no problem. But if both power supplies have their ground wire connected, it trips everytime.

Here is a pic of the setup. If anyone can see what might be wrong...

Thanks,

ScottyMo

[Ken Benedict]

You may be getting a small amount of ground return current going down the white DMX wire to your computer (or DMX interface).

Try plugging your computer into the same power line and see if it trips again.

I've had problems with DMX and had to use an optical isolator (or DMX distro) inline.

Just a hunch.

[LORisAwesome]

Is is possible that the ground and neutral are mixed up. ie ground connected to neutral and neutral to ground by mistake?

[ScottyMo]

OK. So I have isolated the problem down to the power supplies I am using. I have been swapping out PS's during my troubleshooting, but they are all from the same lot of 10 that I purchased from Ray Wu in the late spring. I had a 15amp PS down in the basement that I purchased back in january that I dug up. When I use that one, the problem does not happen. It only happens when using 2 or more of my 16.5amp PS's with grounds connected.

So. My options are...

Buy 10 new power supplies (ouch)

or

Don't connect the ground wires. Just feed the hot and nuetral to the PS

So my question would be... Do I absolutely need the ground wire connected to the power supplies input?

All of my power supplies are in waterproof enclosures. The enclosures are mounted around my house just under the soffits. So they cannot be accessed without a ladder. They are then plugged into my GFCI recepticals.

Thanks

ScottyMo

[GaryM]

What amp are the GFCI recepticals? The only difference in your set up an mine is I use 20 amp breakers. This should not effect the outlets though. The 15 amp should take a 17 amp pull so your 16.5 amp should be fine. One more test I would do if it were me. Take your DMX controller off and test a sequence with just lights and see if it trips. If so then you have narrowed it down to the DMX controller or lights. I do know you said you recreate it with all on (white) But would still test above.

Its likely he's not "pulling" 16.5 A..thats just the maximum rating on the PS. Considering what is being operated, nowhere near 16.5 A load on the circuit.

Curious what you mean by "The 15A should take a 17 amp pull.."...I understand your statement, just curious how you come to that conclusion.

[GaryM]

OK. So I have isolated the problem down to the power supplies I am using. I have been swapping out PS's during my troubleshooting, but they are all from the same lot of 10 that I purchased from Ray Wu in the late spring. I had a 15amp PS down in the basement that I purchased back in january that I dug up. When I use that one, the problem does not happen. It only happens when using 2 or more of my 16.5amp PS's with grounds connected.

So. My options are...

Buy 10 new power supplies (ouch)

or

Don't connect the ground wires. Just feed the hot and nuetral to the PS

So my question would be... Do I absolutely need the ground wire connected to the power supplies input?

All of my power supplies are in waterproof enclosures. The enclosures are mounted around my house just under the soffits. So they cannot be accessed without a ladder. They are then plugged into my GFCI recepticals.

Thanks

ScottyMo

No offense, but have you confirmed your GFCI is wired correctly? And confirmed the issue occurs on another GFCI circuit somewhere else in your house?

[Max-Paul]

I would love to open up one of those power supplies. I wonder if they have a disk cap. between the hot lead and the case? This is good practice to insure that there is no high frequency noise leaving the P.S. on the hot lead and messing with any other electronics in the house via the A.C. lines. It is possible that this cap. is allowing enough current leak to ground and trip the GFI. The ground lead at the power supply is a good idea for the purpose that the case does not become hot. I would look for this noise filter cap first and remove it. Otherwise if you choose to drop the ground wire. Just be aware that if any thing should happen inside the case, that the case could become hot.

[ScottyMo]

No offense, but have you confirmed your GFCI is wired correctly? And confirmed the issue occurs on another GFCI circuit somewhere else in your house?

No offence taken. Should be wired correctly. 10' run from the breaker panel to the receptical box. Black wire into the hot side of the GFCI, white wire into the other side. Ground wire into the green ground terminal. That's it. Nothing else connected.

These are brand new Leviton GFCI I purchased at Home Depot.

Now the interesting thing is that I did as you suggested and plugged into different GFCI's. There is one on my front porch and one in my main floor bathroom. I did not have a problem with either of those!

Think I might run to Home Depot and try a different brand of GFCI

I'll post the results.

ScottyMo

[ScottyMo]

another option, and what I would do, contact Ray Wu and let them know that there is a problem with the PSs you got from them. and see if they will replace them. If you do your option of Don't connect the ground wires. Just feed the hot and nuetral to the PS, why use GFICs? That is like taking the guard off of a table saw. If noone gets hurt then no prob BUT, if someone gets hurt because of this then there is a huge problem. I spent a lot of money having a special outdoor breaker box, underground wireing, and all GFCs installed. Just in case. Also if you have found these to have this problem what is to say there is something else wrong with them tha will cause them to go out during your first week of the show?

Though I have learned a ton in the last 9 months about loads. Amperage, wattage, voltage, etc. I am the first to admit, my knowledge of GFCI, groud faults, etc. is minimal. That being said, my question would be...

All of my bathrooms are protected by GFCI (believe that is code). Does that mean that the GFCI does not protect against problems with things like hair dryers, curling irons, etc that are only 2 pronged with no ground?

[ScottyMo]

well what happends is if there is a short anywhere for any reason and can be a small on it will trip the GFIC. Yes it still protect the user from getting fried by cutting power. Check the breaker for the porch. is it a GFI breaker? or are the outlets GFI (should not be both) Ours is set up that the outside outlets and both bathrooms are on the same breaker and the breaker itself id GFI. but the outlets are normal outlets but does the same thing. The box I have outside is a dedicated 100 amp box then i have 14-20 amp breakers that then go to 14 GFI outlets in the yard and on the house. I B Wired, lol.

The outlets on the porch and in the bathrooms are GFCI, not the breakers

the brand of GFCI should not matter. The amp will. First check the amp of the GFCI on the porch. then check the amp of the breaker on the porch and the amp of the breaker you are using for lights. see if all same

The ratings are the same for both the new and the old GFCI's 125v 15amp, 60 Hz

[ScottyMo]

what about the breakers? I bet the porch one is 20 amp. and I think you said the new one for lights was 15 amp. If this is the case then this could be the problem. An outlet of 15 amp will handle 17 amps but if the breaker is a 15 amp then this could be a problem with the 16.5 amp PS. What I do not get is if that is the problem then why does the breaker not throw instead of the outlet. But check that and will see what I can find out.

All of the GCFI outlets, old and new, are hooked to 15amp breakers on the panel.

The PS does not draw 16.5 amps. Remember, that is the 12v output of the PS (200w). The 110v input is only 4.5amps.

[ScottyMo]

ok. I was just going but what you said in your original post. This has me stumped, like you. why would it work with old breaker and old outlet but does not work right when used with new outlet and new breaker. next question. the new breaker used with lights, is it the same manufaturer and type as the breaker box?

Yes. They are the same Stablok breakers as all the others in the panel. In fact, one is new, the other was already in the panel. The only other thing connected to the old breaker is one outlet beside the panel. Just in case, I tested disconnecting that outlet and still had the problem.

[ScottyMo]

wow, starting to hurt my brain on this one. I am guessing noone else has any ideas or they would have said something. You have tested everthing you can but what gets me is you do not have problems with the old outlet and breaker but do with the new one but they are the same. Just a wild question. what guage wire did you use from the breaker to the outlet? and you would not happen to have an electrician friend there would you?

I used standard 14\2 from the outlet to the panel. I hooked up the outlet and ran the wire to the panel. My step-father came over and did the panel work. (I don't like touching the panel) Though not a licensed electrician, he knows what he is doing and worked for the utility company for 25 years. I asked him to pop by tonight to double check my outlet install. But I am not holding out much hope that there is an issue to be found there. Pretty simple. Black wire connects to black, white to white, and ground to ground :-(

I'm starting to feel defeated over here :-(

[MikeyRo]

OK, worth a shot, if you want to go to the trouble... Take the outlet from the porch and install it in your lighting box and serif the GFCI trips. If it does, it has to be something in the wiring. If it does not, then I would bet it is the outlet it's self. Maybe even try the lighting outlet in your porch box and see if it trips there when using the lights

Just a thought for thoroughness sake.

[GaryM]

what about the breakers? I bet the porch one is 20 amp. and I think you said the new one for lights was 15 amp. If this is the case then this could be the problem. An outlet of 15 amp will handle 17 amps but if the breaker is a 15 amp then this could be a problem with the 16.5 amp PS. What I do not get is if that is the problem then why does the breaker not throw instead of the outlet. But check that and will see what I can find out.

This has nothing to do with it. The issue is not a current draw issue.

A power supply rated at 16.5 A does not mean it draws 16.5 A (AC).

A GFCI is not typically going to trigger on current draw..it is to protect against a ground fault. Totally separate from an issue where you are drawing more current than what a particular circuit is rated for.

Circuit breakers protect against excessive current draw...GFCIs protect against ground faults.

wow, starting to hurt my brain on this one. I am guessing noone else has any ideas or they would have said something. You have tested everthing you can but what gets me is you do not have problems with the old outlet and breaker but do with the new one but they are the same. Just a wild question. what guage wire did you use from the breaker to the outlet? and you would not happen to have an electrician friend there would you?

And its not a wire gauge issue either. Trust me on this one.

[GaryM]

No offence taken. Should be wired correctly. 10' run from the breaker panel to the receptical box. Black wire into the hot side of the GFCI, white wire into the other side. Ground wire into the green ground terminal. That's it. Nothing else connected.

These are brand new Leviton GFCI I purchased at Home Depot.

Now the interesting thing is that I did as you suggested and plugged into different GFCI's. There is one on my front porch and one in my main floor bathroom. I did not have a problem with either of those!

Think I might run to Home Depot and try a different brand of GFCI

I'll post the results.

ScottyMo

Logic would say it is wired wrong. My bet would be you have something done incorrectly at the panel side. Doubtful you have two defective GFCIs right out of the box.

You don't get do-overs when making mistakes with electricity, and a lot of the advice you are getting here is just 100% factually incorrect. It would be laughable if it wasn't regarding something that can cost one their life.

Do yourself a favor and call an electrician.

[Max-Paul]

well what happends is if there is a short anywhere for any reason and can be a small on it will trip the GFIC.

This statement is not correct as it is. In the case of a resistive load that has a few coils shorted, and as long as the current draw is still within the max rating of the breaker. Nothing happens other that the resistive load will get hotter. Now lets say that the short is to a piece of external metal surface and a person touches this metal surface. Nothing still will happen, unless that person is also touching a grounded surface. Thus there is a current path to ground. This is what the GFI is all about. Detecting a flow of current that is going to ground and not to neutral. A statement to sum it up would be "The amount of current flowing out on the Hot lead must be the same as the amount of current flowing back onto the neutral lead. With the exception of a tolerance of about 5 or 10 mA."