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View Full Version : Solid state/remotely resetable GFCI circuit?



djulien
12-24-2008, 06:34 PM
Does anybody know of a reliable, low-cost, not-too-complex solid-state version of a GFCI outlet (DIY or pre-built)? (planning for next year, too late for this year)

During wet weather, my GFCI outlets trip, which is what they are supposed to do. However, I'm wanting to (1) automatically detect when that happens, and (2) be able to reset it remotely after a delay period.

I think I can figure out how to do (1) - just plug a relay or a ZC detection circuit into the protected outlet, and monitor the output. Or is there a better way?

(2) is where I need help. The GFCI outlets I'm using sound like they have mechanical contacts in them, because I hear a "click" when it trips, and I have to physically push a button which feels like it is relatching a spring mechanism. Is there a reliable electronic alternative, that could be reset after a delay period or under software control? I would probably want it to retry one time a few seconds later in case it was a 1-time problem, but then not retry again until, say, 15 seconds later in case it is a real problem, and then probably retry, say, every 10 minutes thereafter so it knows when things are back to normal.

Ultimate goal is to have an audible alarm in the house and also an HTML update on a web site, so if anybody has done something like this I'd be interested in learning about how you did it.

thanks

don

pete
12-25-2008, 05:32 PM
An audible alarm would be easy. Just an icecube relay coil feed off the gfci and a non gfci feed to its NC contacts feeding a beeper. Gfci on holds NC open.. GFCI trips contacts close and you have audible alarm. Could also feed a dri set of contacts to a sim. joystick circuit and use kiwichristmas joystick plugin to have Vixen notify you somehow that power has been lost to part of the display. Now as far as remote reset goes.. do you think this is wise? Wont you want to be there to know why it tripped?


Pete

Macrosill
12-26-2008, 05:53 PM
.......Could also feed a dri set of contacts to a sim. joystick circuit and use kiwichristmas joystick plugin to have Vixen notify you somehow that power has been lost to part of the display. .......


Pete
Thinking out loud here and my geekness may show:
Lets do as Pete stated but have the pc automatically send me a text on my cell phone. Should be doable. Use the launcher in Vixen to open an auto email program or something similar.

djulien
12-26-2008, 05:53 PM
Now as far as remote reset goes.. do you think this is wise? Wont you want to be there to know why it tripped?

Well, yes. But I also don't want to be baby-sitting the display constantly during wet weather, either. I figured that 1 retry right away, another one 15 sec later, and then periodic retries every 10 minutes after that would be a safe compromise. If it was a one-time trip, then the system would return to normal operating mode by itself after a brief delay. If there was an on-going problem, it would keep tripping and resetting, but not so often as to cause a dangerous condition.

My ultimate goal is to make the display auto-restarting after a problem, and also update a web page and/or yard sign with current status automatically. (so far I've been doing it manually).

don

djulien
12-26-2008, 06:24 PM
have the pc automatically send me a text on my cell phone. Should be doable. Use the launcher in Vixen to open an auto email program or something similar.

I like that idea. So the launcher would be triggered by something like a relay on the GFCI circuit? Would the trigger wait until the current sequence or program was done, or is there a better way to make that happen?

don

Macrosill
12-26-2008, 06:28 PM
I envision a set of pins, say on an unused parallel port, that gets a no relay. The relay is held open by a feed from the gfci. When the gfci trips the relay closes and shorts the 2 parallel port pins. This would trigger an event in Vixen, using the trigger plugin, and launch a third party application that would send out a text message to my cell phone or send an email.

ben
12-26-2008, 08:15 PM
I envision a set of pins, say on an unused parallel port, that gets a no relay. The relay is held open by a feed from the gfci. When the gfci trips the relay closes and shorts the 2 parallel port pins. This would trigger an event in Vixen, using the trigger plugin, and launch a third party application that would send out a text message to my cell phone or send an email.

SWEET! I love it!!! now get it done and report back when i can use it ;)

Ben

Aurbo99
12-27-2008, 05:15 PM
For the no power alarm circuit, check this out;
http://www.electronics-project-design.com/PowerFailureAlarm.html

Add a 3 plug adapter at the GFCI plug, one plug goes off as normal, the second one is used to plug this little doohickey into. the 3rd plug in is unused.

Or if you do as I did, one GFCI runs a single extension cord, and the second outlet is available for this device.

A quick mod on this would be to take either the LED and/or the buzzer and extend it into the house where it can be seen/heard.

Jeff Millard
12-28-2008, 12:00 AM
Solid State differential products exist. They are used all over the power grid in relay protection. SEL (Schweitzer) GE, Westinghouse all make digital products for the purpose of comparing load flow. Most all of these are cost prohibitive though. Too bad, as they're all easily user programmable. The auto reset function is simple to program. Output an alarm to one output when you are nearing the trip setting, have the trip initiate a reclose of the circuit. Now you've got me wishing I could get my hands on a nice SEL diff relay and some CTs....

Jeff

djulien
12-28-2008, 07:30 PM
SEL (Schweitzer) GE, Westinghouse all make digital products for the purpose of comparing load flow. Most all of these are cost prohibitive though. Too bad, as they're all easily user programmable.

Why are they expensive? Is it because they can be, since the target market is commercial/utility grid, or are there some fancy parts in there that just cost a lot? Do you know of any schematics for them, or are they proprietary trade secrets and/or patented?

don

Jeff Millard
12-29-2008, 11:35 AM
Why are they expensive?
since the target market is commercial/utility grid, or are there some fancy parts in there that just cost a lot? Do you know of any schematics for them, or are they proprietary trade secrets and/or patented?

don

The things I was speaking of are expensive for many reasons.

Processor based relay protection is becoming the "new construction" industry standard. Retro fitting is taking place where upgrade for supervisory control of equipment is needed, required or desired. Most of the original mechanical relays work as good today as they did the day they were installed (some in the early 1900's here in this area) but they are lacking in supervisory control. It's becoming a requirement to be able to operate, and know the status of as much of the distribution system as possible. Federal and State governments are setting the guidelines for this, so the industry is at the mercy of those who develop the hardware and software to fill the need.

Companies that provide the electrical industry with the new processor based relays have overhead for R and D, and liability issues. These relays aren't expensive to manufacture, but they are costly to design, test, modify, develop and support. Surely there are patents, but the information I've been able to gather to support them was easily available to any 'customer' of these products.

None of them are meant to protect a single circuit of 120V. They are mainly meant to protect 3 phase primary, using current transformers and potential transformers stratigically placed to protect something specific. Take for instance a 69KV to 13KV transformer in a common 13KV "H" station. The 69KV circuit feeding the transformer would have a load break disconnect that could be opened directly from an output of a Differential relay. That relay would also have an output that would trip a lockout relay. The CTs on the 69KV side, would be compared to CTs on every distribution feeder breaker that transformer feeds, totalled up. Everything coming into the station, would have to equal everything leaving the station, or the circuit trips. If that happens, the load break clears the transformer... all the feeder breakers trip on loss of potential from the transformer... and the lockout relay prevents them from automattically reclosing. Plain ole' simple Diff.

I am sure there are products from some of these and other companies that are meant for single circuit 120V use. But I have no experience with those items. I was merely suggesting that these things exist, as I install and maintain them daily at work. There are some pretty compact relays from GE. Most diff circuits have regular and back-up protection. There are two reasons for this, the obvious one is if one fails... the other reason is for maintenance. Take one out of service for a day to maintain it and the other is there to protect an in-service asset. One I put in a 26/4KV unit sub was no larger than a demand meter.

Try looking on the websites for the named companies to see if they list products like you are interested in. From my experience purchasing relays and devices used for the electrical industry, I can tell you that I bet they won't be cheap.

Jeff

chris2879
01-05-2009, 01:03 AM
This is real intersesting. I was out of state when i was having GFI trips! I immediately thought it would be great to be able to reset the GFI remotely. I will keep my eyes out and see if I come across any thing like this!

djulien
01-06-2009, 01:38 AM
This is real intersesting. I was out of state when i was having GFI trips! I immediately thought it would be great to be able to reset the GFI remotely. I will keep my eyes out and see if I come across any thing like this!

Yes, that is the scenario I ultimately have in mind. I'm not too keen on calling up the neighbor to have them reset it for me each time it trips.

don

petefats
01-06-2009, 01:57 AM
Um... stoppit.

You're not fixing the problem, you're begging for another one. If there's enough leakage to trip your GFCI (*G*round *F*ault!!!) you should fix it.

http://diylightanimation.com/index.php?topic=778.0

Photovor
01-06-2009, 09:21 AM
This may be relly out there- but after you have the alert system in place, you could rig some sort of solenoid to either hit the reset button, or reset a breaker. You'd need something with a bit of power. Harder things have been done though.

Warlock
01-07-2009, 02:06 AM
Would be cool to have something like that..Calling your cell..

Personally I'd like to know what causd it to trip and I believe I've figured out why...


Please indulge me for a minute for a bit of a story and you will see why I think I got this problem figured out and solved..

My neighbours and I had one hell of a time trying to figure out why the hottub breaker was tripping..It's a new GFI breaker that has an extra pigtail wire which goes to box ground.Now ever so often it would trip like a pig but we could never figure out why..Well we figured it out this way..Wire guage was over kill to handle the amount of draw..It was the only thing on the circuit so it wasn't an overload issue...Proper outdoor outlet with cover etc...It was really driving us nuts till I remembered I had a huge problem with 1 spark plug wire on my old van do the same shorting thing...I simply used a dielectric grease on the inside of the wire (the boot) to block out all moisture and it worked..So we coated the plug wires on the outlet and no more moisture tripping which is what I think the problem is...Your GFI'S are tripping cause of moisture in the air reacting with the copper inside the receptical...So my point is try using dielectric grease on the plug to seal out moisture and outlet plugs with grease on them for your open outlets...You can get dielectric grease for like $7.00 at any auto parts place.Worth a try as it worked for me all winter as I also use a GFI breaker for my lights as it was easier to wire up then a full GFI circuit.Both are really sensitive to moisture..It also reminds me of when I was in high school and how they tested them with a spray bottle of water spraied directly into the outlet...Once it tripped it was reset and that is how they knew it was working...Keep it inmind when you think of GFI...The grease doesn't take away from it tripping incase fo a short.It simply displaces moisture taht is seen at the outlet itself..Outside is a damp place..All my cords were coated in this stuff...No trips at all...Hope this helps..
Joe...