LMS Sieg SC4 Popping My Ground Fault Interrupter

[Ken I]

Ditto Sailplane driver's caution on open circuit CT's - normal practice is to short the output when not in use. One of those rare occasions where it can literally burn out open circuit but is quite happy shorted.
So it needs a burden resistor for the test I was suggesting.
If you have a snap on you can do the neutral/live & neutral/earth checks with that. I have an AC/DC snap on "attachment" that plugs into a meter via banana plugs - it gives 1mV/A - handy for connecting the output to an oscilloscope.
I'd try exchanging the surge protected strip for a non-protected strip - those things often have filter caps, MOV's & GDT's transient surge tubes etc. down to earth.
Might be an idea to open it up / diagnose it.
These things are often rated for the degree of permited transient ie 300V, 400V & 500V for 120V outlets. Lower limits are good for protection but more prone to tripping.
The other thing you could try (if the strip is the problem) is to lift the ground end of the protection devices from earth and put them down to neutral instead - so the transient is more likely to ballance out at the GFI although phase shifts can still dick with it.
This modification obviously destroys the strips ability to protect you from a simultaneous rise in your live and neutral voltages relative to earth.
Perhaps you can re-engineer the strip to a low sensitivity to neutral (300V) and a much higher sensitivity (500-1000V) to earth.
The GFI trips might just be symptomatic of the strip actually doing its job and your problems are caused by a ratty supply - or something on your system (neighborhood / locale) is generating overvolt spikes which are being dragged down to earth by the strip.
Obviously if you have had equipment failures caused by overvolt transients - and that's why you installed a surge protection strip - then its doing its job - leave it in and live with the occasional trip or try and hunt down and kill the source of your tormentor.
Regards, Ken

 

[SpringHollow]

I do not know what you have plugged in but there are many things that still draw some power when "turned off".

 

[bluejets]

I do not know what you have plugged in but there are many things that still draw some power when "turned off".

They don't "draw power".
What they do is provide a leakage path from the Neutral.
Which is why, as they have already stated, they have pulled the plug on all devices.

In my experience, there is usually one they miss somewhere such as a submersible septic pump or an added fault such as an outdoor outlets that has become a home for a million or so ants.
Even had it where ocean breezes blew up though the cavity walls and over the years created earth leakage paths in the outlets themselves.

Diagnosis can be troublesome at times even with the correct procedure, test instruments and the qualifications.

 

[ccolby]

Your problem is the radio-interference reduction capacitors in the various components. As they absorb from and release current into the circuit, they confuse the GFCI circuitry. Vintage military-spec Porter-Cable portable belt sanders are the classic example in which the included instructions warned about this effect. The only easy solution is to toss the GFCI and reinstall the less-intelligent receptacle and then don't do any machining while standing bare-foot in the water puddle on your basement floor. You can Google all, of this. That's how I learned about it after my surge-arresting outlet strip continually tripped the GFCI in my shop.

 

[SpringHollow]

I was referring to some "power bricks" connected to equipment that is turned off, devices that have sensors always on checking for wireless remotes, etc. They are consuming power/drawing current since they are not turned completely off even though the power switch on the device is turned off. A television is a perfect example of this.

 

[bluejets]

I was referring to some "power bricks" connected to equipment that is turned off, devices that have sensors always on checking for wireless remotes, etc. They are consuming power/drawing current since they are not turned completely off even though the power switch on the device is turned off. A television is a perfect example of this.

If the switch powering the "brick" is off then no current flows. (except the aforementioned leakage path through the Neutral.

What you are getting confused with is smps units in standby where power is still applied to the input and the smps generates a 5v dc standby voltage waiting for the press of a remote button or what have you to power up the main output.

 

[SpringHollow]

I am not confused. I understand what you are saying. What I said was for those who turn off the power switch on a device and think it is off which is not totally true for some devices. I was not referring to the plug strip power switch. Earlier, it was said things were not turned on and that is why I said what I did. I appreciate the effort you have put in to explain things.

 

[CFLBob]

I am not confused. I understand what you are saying. What I said was for those who turn off the power switch on a device and think it is off which is not totally true for some devices. I was not referring to the plug strip power switch. Earlier, it was said things were not turned on and that is why I said what I did. I appreciate the effort you have put in to explain things.

And with no disrespect intended, the reason I didn't reply is that it's something I've known for about 50 years. Even back then, there were "instant on" TVs that worked by leaving the tube filaments on all the time, so that when you turned on the switch they didn't take 20 or 30 seconds to warm up. I'm well aware that the Dell computer that I'm cleaning up has a green LED shining off the back panel, even though they want us to believe it's off. Something is obviously always on to power that LED.

What you posted is good for someone who comes across this thread next month or next year that doesn't know these things, so it's valuable for other people.

 

[CFLBob]

I came across something interesting while changing out all the outlets. It just doesn't look like it should have been there.

That's the neutral side. Could that cause leakage current once every couple of months? Or every couple of days if the conditions are just right? (Just wrong?)

I will continue the experiment of only plugging in the AC outlet strip that plugs into this outlet when I need to use it. For a couple of months.

 

[ignator]

Bob, any luck finding root cause of this tripping? Last post was a month ago.

 

[CFLBob]

Bob, any luck finding root cause of this tripping? Last post was a month ago.

Tomorrow will be four weeks since the last time it tripped. It has gone longer without tripping and then started again, so I'm not convinced, but so far, so good. To be honest, it will probably have to be six months before I start to believe it's fixed.

 

[ignator]

Yes, the humid day's of summer yet to come.

 

[SailplaneDriver]

If you just want info on how to troubleshoot GFCIs, skip down to the bullet list.

I spent yesterday helpting a friend put in a transfer switch so he could power a subpanel from a generator during power outages. The generator itself has a GFCI. With the generator running and no load, we could plug the in the cable and everthing was fine. When we connected the cable to the transfer switch, again no load and the transfer switch on utility power, the generator's GFCI would trip. Testing of the cable and the transfer switch showed no problems. So I did what any safety concious person would do - I disabled the GFCI by disconnecting the shunt trip to the generator main breaker. This is NO a safety issue. I explain why not below.

The generator is 120/240v and has an internally grounded neutral. That is, the white wire (neutral) of the generator is connected to the green wire (ground or earth for you Europeans) and the generator chassis. The house is also 120/240V (obviously) and has its neutral grounded at the utility service (mains again for you Europeans). The cable which will connect the generator to the house is four-wire, two "hot" wires, one neutral wire and one ground wire. When the cable is connected from the generator to the house, there is a loop in the circuit created by the neutral and ground wires; the neutral is connected to ground at the generator and the neutral is connected to ground at the house. This loop is what is causing the generator GFCI to trip.

Modern GFCI electronic circuits have a self-check feature that is intended to confirm proper installation and proper opeartion after installation. One of these self-check tests if to determine if the neutral has been improperly earthed downstream of the GFCI. The GFCI puts a small pulse into the neutral and checks to see if it comes back through earth. That self-check feature is what was tripping the GFCI in the generator.

The above is why I have been repeatedly telling people who have GFCI nuiance trips to check to see if the neutral has a ground downstream of the GFCI. This is a common causes of GFCI misoperation.

Now, why disconnecting the GFCI does not pose a safety hazard. The generator has no provisions for removing the ground to the neutral. The neutral to ground connection cannot be removed from the house electrical service since that would be a huge safety issue. Switching the neutral to the subpanel with a three-pole transfer switch that switches the neutral as well as the hot wires would work for most installation but not in this case; the homeowner has a battery backup system as well and a bypass from the main panel to the subpanel - don't ask why. Even if I could removed the internal ground from the generator, the GFCI only looks downstream of the ground location. In this case, the GFCI on the generator would only look INTO the generator and would not protect the cable or any other cords connected to the generator. There is no safety issue since the only load is the house wiring and it is already protected in accordance with safety standards. Additionally, I warned the homeowner not to use the receptacles on the generator without reconnecting the GFCI trip.

The moral of this story is check your neutral for grounds after the GFCI. Here are the other checks I recommend:

• If the GFCI won’t reset, make sure that there isn’t an actual ground fault on the circuit.
• Make sure the GFCI has been installed properly and is functioning properly.
• Check if there is an outdoor receptacle on the same GFCI circuit. If so, check it for moisture and insects.
• Unplug everything else from the GFCI protected circuit and see if the problem persists.
• Don’t use plug strips with surge protection.
• Don’t use extension cords.
• There can be problems if there are too many receptacles on one GFCI. The total one-way wire connecting all the receptacles should not exceed 100 feet. That includes any cords plugged into the circuit.
• Make sure the line and load wire on the GFCI are not reversed.
  
• Have an electrician check to see if the wiring is proper at the GFCI and all downstream receptacles.
• Make sure there isn’t another GFCI connected downstream of the one that is tripping. Connecting GFCIs in series can cause nuisance trips.
• GFCIs can fail. Replace the GFCI.

If all else fails, install a dedicated circuit and dedicated GFCI for the device.

No, there is no exception for installing GFCIs in garages and shop areas. The exception was up until the 2005 edition of the National Electrical code. It was removed in 2008 and all subsequent editions.

No, I did not plagerise this from LMS - I sent it to LMS.

I am a licensed electrical engineer in California (previosly in several other states). I can provide my license number if you want to verify my credentials.