Gfci circuit #1

[rlfrazee]

This circuit is a test circuit to introduce various faults through spst switches on the gfci upstream.


http://images.snapfish.com/3394779523232%7Ffp45%3Dot%3E232%3A%3D%3B9%3A%3D688 %3DXROQDF%3E2323482%3A257%3A6ot1lsi

[6pack]

Rl?? what are the switches for? they (2) appear to be dead shorts.#'s 1&2 #3 a heater using grounding conductor? #4 a grnd fault neu to grnd? Maybe were on two different wave lenght's here?,

[rlfrazee]

Rl?? what are the switches for? they (2) appear to be dead shorts.#'s 1&2 #3 a heater using grounding conductor? #4 a grnd fault neu to grnd? Maybe were on two different wave lenght's here?,

Wannabee, sorry should have been more clear. They are indeed faults on the circuit to see how the Gfci behaves that is protecting the receptacle downstream. Each switch was closed individually to create a fault on the circuit under load and no load. Then the switch was opened the gfci reset or breaker and the next switch closed etc..Remember I did some tests on gfci's and this is the test circuit I set up in our training lab. #3 is a 15K resistor in series with the switch to produce an 8ma leak on the ungrounded conductor. Just wanted you guys to look at it to see if it was drawn correctly under those circumstances. Guess I thought you could read my mind....RL

[Wgoodrich]

The circuit is drawn correctly and quite understandable. The shorting switches depict all four types of dead short conditions that should be tested in your experiment. You might add a shorting test between hot and neutral with the 15 ohm resister as you did between hot and equipment grounding though.

Prediction load side of GFI ;

hot to equipment ground breaker trip, GFI destroyed.
Hot to neutral breaker will trip GFI destroyed.
Hot to equipment ground through 15 ohm resister. GFI trip and survive. Breaker trip second.
Hot to neutral through 15 ohm resister. GFI trip and survive. Breaker trip second.
If you change to a much higher resister hot to equipment grounding short through large resister GFI trips but breaker stays on.
If you change to a much higher resister hot to neutral short through large resister GFI holds but breaker will trip over time.
Neutral to equipment grounding short GFI trip breaker will hold.

Curious how close I get to actual testing results.

Curious

Wg

[rlfrazee]

Wg, I dont think anyone has dismantled the test circuit we built in the lab but not sure if I will be able to do the hot to neutral test with 15k resistor and higher resistor test as Ford is closing our building this Friday. No one losing job just moving to new building. Actually realized I should have made this test hot to neutral through resistor when I took apart gfci that had been destroyed noticed the the test button circuit was a hot to neutral short through a 15k resistor. My resistor came from radio shack but just thought, I could probably get one out of a gfci receptacle tester or wire the tester via a three prong plug into the circuit and use it to produce the fault. Will do the extra tests if possible, how much higher do I need for this resistor? Thanks for your assistance in my search for knowledge.....RL

[Wgoodrich]

Any of the testing you are doing will add to knowledge and understanding. The high resistance would duplicate a high leakage not enough to burn out the GFI but will hit enough load to push the breaker in amp draw per line neutral and short circuit to activate the GFI but not cause the breaker to trip going to equipment grounding. A larger resister in the hot to grounding connection will allow the GFI to react without destroying it. What you are doing is a seat of the pants guess work in how much resistance it takes. Just do what you can in your experiments. I was just adlibbing to what you already had trying to increase avaialable experience in your testing experiment. My guess a 30 ohm resister should allow the GFI to survive to give you a true reaction GFI / Breaker results but that is a guess. Undamaged GFI after test but pushed to its limits would give you best accuracy of ability of the GFI protection. Let us know what you discover. Great that you are taking the time to do the lab research. Got me curious the outcome report.

Good Luck

Wg

[6pack]

Rl, thanks to WG for understanding what your intension's were here. I quess you or anyone can see how poor a reader I am. I had thought you were making a schematic of what I was'nt sure. Was curious myself, I guess knowing you knew better, I should have read thru that. My applogies. At least I was able to see your faults(deliberate). Feel like a schumck! will follow along now that I'm on track. :o

[rlfrazee]

Wannabee your not a schmuck. I was not clear at all and edited to make things understandable. Probably thought I was suicidal with your first impression of that circuit. I really had a good laugh thinking about it. Anyway the results I hope to post tonight. Very difficult because so much info and things that should be mentioned. Also a few oversights that Wg pointed out but hope it is a reasonable and accurate testing of a gfci. Dont have the knowledge I should to do this as a lot of guess work on my part but curiousity got the best of me.....RL

[6pack]

Thanks in seeing my oversite. "Learn To Do By Doing" Your iniative well appreciated. Remember though "Curiosity Killed the Cat" don't go getting to curious about "Lightning Strikes". Ha Ha Tanks again.

[rlfrazee]

Thanks in seeing my oversite. "Learn To Do By Doing" Your iniative well appreciated. Remember though "Curiosity Killed the Cat" don't go getting to curious about "Lightning Strikes". Ha Ha Tanks again.

I think my curiousity appetite is almost satisfied for the time being...Have a great Xmas.....RL
About those lightning strikes.....HMMMMM??