GFCI keeps blowing

[Sawdustguy]

I'm not saying it's not possible, but I would think even a few miliamps would trigger the audible continuity check on a Fluke Meter. By all means, check everything.I'd just be more suspect of a leak. jkarps expansion theory seems logical too since it's fine until things get heated up where as if it was teh JBweld shorting, it'd be instant.

I agree with you...check everything. I am not saying the J-B Weld would cause a direct short. I am suggesting it is a high resistance short maybe a couple thousand ohms lending to your leakage theory. Or then again I may be barking up the wrong tree entirely. It is just a theory. If I had a highpot machine I could try an experiment.

 

[gunmetal]

I work on carpet cleaning equipment. We test every unit on a gfci circuit before it goes out the door because of liablility issues. The craziest things can blow a gfci. I have seen residue from powdered cleaning solution cause a slight short to ground. I have seen an element that when hot has a short from thermal expansion, but has nothing when cool.

 

[Quaffer]

A decent multi meter capable of measuring in the Megohm range should detect the problem. Run the heat stick until the GFI trips, unplug the heat stick, then measure the resistance from hot to ground, neutral to ground. Any reading less than infinity is a smoking gun. Be sure you are not touching the terminals because your skin resistance will throw off the measurements.

Years ago I had the GFI for the garage tripping intermittently on me. Turns out it was the outdoor light cable, buried in the ground, taking on moisture when it had rained and drying out in between. Look for cracks in the chord also.

 

[Cybershadow]

true, but i have permantly sealed my contacts with jb weld. I need to find a way to liquify silicone caulk to pour around the element instead of jb weld. Silicon will allow me to disassemble the heatstick. I'll probably just have to build a new one and be extra careful.

 

[IrregularPulse]

true, but i have permantly sealed my contacts with jb weld. I need to find a way to liquify silicone caulk to pour around the element instead of jb weld. Silicon will allow me to disassemble the heatstick. I'll probably just have to build a new one and be extra careful.

It seems insulating these heatsticks is the most annoying part of electric brewing. I'm interested in these that another user purchased premade. I won't pay their price, but it appears to just be large heat shrink around everything. I grabbed a large piece from work and plan on trying it out. I am considering putting orings on either side inside the heat shrink as well.

 

[jgln]

I see in your original post you mention a fork. You are not putting that fork in the outlet are you? That could cause it.

...sorry, I thought it was funny to see the typo and could not help myself.

 

[DeafSmith]

One possibility is moisture getting inside the element. It sounds similar to a problem I have had. I use a rebuilt drop-in electric range top as my brew stove (I rebuilt it to get three heating coils close enough together to get my 10 gallon Megapot over them.) During initial testing, I found that the GFCI would trip after a minute or so of heating, and any one of the three coils alone would trip it. If I turned the stove off for a few minutes, and then back on, it would trip more quickly, sometimes immediately, sometimes after only a few seconds. I wanted to do a test to see how long it would take to heat my water to boiling, so I temporarily wired around the GFCI to run the test. The day after the test (45 minutes with the stove on full blast), I put the GFCI back in the circuit to trouble shoot the problem and the problem was gone. My conclusion is that the coils get moisture inside them, which vaporizes after a minute or so of heating, causing the GFCI to trip. If you continue heating the coil (without the GFCI in the circuit) it bakes the moisture out and everything is fine for a while, but the coils will accumulate moisture if left unheated for weeks or months. I solved my problem by simply wiring a regular 30 amp breaker inside my GFCI box, in parallel with the GFCI breaker. At the start of the brew day, if the GFCI trips, I turn on the regular breaker, run the stove for 5 minutes to bake out the moisture, then turn off the regular breaker and turn the GFCI breaker back on and continue without problem.
I know those water heater elements are designed to be used underwater, unlike the coils on my stove, but it does sound to me like water could be getting either into the element or around the connections to the element, and it wouldn't take more than a very tiny amount to trip a GFCI.

 

[Cybershadow]

I'm starting to think it may be a leak too. That is why i need to find a different method other than jb weld. I am gonna hop on google and see what i can find. Jb weld is to permanent and i need a better way to be able to disassemble and troubleshoot.. I'll post what I find for sure.

 

[Quaffer]

true, but i have permantly sealed my contacts with jb weld.

I meant probing the prongs of the plug. That would settle the issue that there is indeed a ground fault in the stick, if that is not already established 100%.

Enough people have used JB weld to pot electrical connections that I think it is not the most likely culprit, notwithstanding it has iron powder in the mix. It is like you said, though, a permanent assembly.

 

[jkarp]

A decent multi meter capable of measuring in the Megohm range should detect the problem. Run the heat stick until the GFI trips, unplug the heat stick, then measure the resistance from hot to ground, neutral to ground. Any reading less than infinity is a smoking gun. Be sure you are not touching the terminals because your skin resistance will throw off the measurements.

Actually, that's not a very good test. It could be there's a crack in the element that's taking in water when heating. GFCI trips based on current, not voltage so testing resistance isn't a reliable method.

 

[Quaffer]

Actually, that's not a very good test. It could be there's a crack in the element that's taking in water when heating. GFCI trips based on current, not voltage so testing resistance isn't a reliable method.

Oh but it is. Ohms law relates voltage, current, and resistance and it applies here like everywhere else. Water causes an easily measured resistance. The resistance causes the ground current, and we are measuring that resistance.

 

[Cybershadow]

I just want to apologize to everyone. I can honestly say "I was wrong". My jb weld failed and the water turned it into chalk.

I originally used about 2 tablespoons of acetone to thin it and jb weld says to use no more then 1 teaspoon. People on here said it would work but it would just take longer to cure. Maybe the acetone just wrecked the jb weld apart like acid or something

 

[P-J]

Thanks for the update. It's much appreciated.

You really demonstrated the critical need for everyone to seriously consider GFCI protection with electric brewing. Electricity in a wet environment? You betcha!

 

[Chefkeith]

I'm just glad you're safe, Cybershadow. It is for this reason that I'm not a fan of heat sticks. I would never put electrical connections underwater, even though many hundreds of people do. I use the same setup that Kal uses, and it's never leaked. Never. Not even during testing; it worked the very first time.

Sure, it costs more money to mount an element inside of a kettle, but I believe that it's probably the safest way - and you can't put a price on that. As an added benefit, if I blow an element, I can replace it with a backup in minutes.

Anyway, thanks for posting the outcome; it took a lot of guts to make that post, and hopefully, it will help somebody else that's in the same boat.

Successful autopsy!

 

[jkarp]

Oh but it is. Ohms law relates voltage, current, and resistance and it applies here like everywhere else. Water causes an easily measured resistance. The resistance causes the ground current, and we are measuring that resistance.

I'm quite aware of Ohm's law.

How exactly did you propose to test resistance under operating conditions?

 

[jkarp]

I originally used about 2 tablespoons of acetone to thin it and jb weld says to use no more then 1 teaspoon. People on here said it would work but it would just take longer to cure. Maybe the acetone just wrecked the jb weld apart like acid or something

Wow. I'm one of the ones who said it should be OK. I stand corrected as J-B Weld DEFINITELY should not have done that!

On the upside, you should be able to re-use the element...

 

[jkarp]

Sure, it costs more money to mount an element inside of a kettle, but I believe that it's probably the safest way - and you can't put a price on that. As an added benefit, if I blow an element, I can replace it with a backup in minutes.

Yup. I said exactly the same on Basic Brewing. Heatsticks may be cheap, but if you're going to have a dedicated brew kettle, you're far better off doing a mounted element with a simple weldless fitting.

 

[Quaffer]

Like I said in this post. Let me be more specific. We run the suspect heat stick until the GFI trips. This means that we had at least 4mA of current between hot and ground, which in turn means that the leakage path has a resistance of at most 30 KOhm. We now unplug the heat stick and measure resistance between hot and ground (the ground can be on the pot as well). We should see some resistance, it may fluctuate a bit, but it is not going to be far from 30K. The leakage path was already created seconds ago and it will still be there, if the heat stick caused the ground fault.

The GFI has already indicated that there is a ground fault. This resistance measurement is one way to verify what the GFI already indicated, or show that something else is at fault.

 

[jkarp]

The leakage path was already created seconds ago and it will still be there, if the heat stick caused the ground fault.

Right here's your problem.

Elements cool enough to touch almost instantly when shut off. If the problem really were thermal related, the short may disappear before you can get your meter on it. Meanwhile, monitoring amperage to ground during operation would show you in real-time what the GFCI is seeing.

 

[Quaffer]

Right here's your problem.

Elements cool enough to touch almost instantly when shut off. If the problem really were thermal related, the short may disappear before you can get your meter on it. Meanwhile, monitoring amperage to ground during operation would show you in real-time what the GFCI is seeing.

I thought you said water leaking in was the problem? It would still be there.

 

[ClaudiusB]

I agree with you...check everything. I am not saying the J-B Weld would cause a direct short. I am suggesting it is a high resistance short maybe a couple thousand ohms lending to your leakage theory. Or then again I may be barking up the wrong tree entirely. It is just a theory. If I had a highpot machine I could try an experiment.

Thanks for reminding me about a nightmare I had.
A few years ago I run into a similar problem with epoxy.
Snubbers and current sensors for motor drives were potted with black epoxy and ran at high temps.
Some devices shot the drives down after running from minutes to hours giving over-current indications.
Improper mixing and the high temp created enough leakages current to trip the sensing circuit.
Changing to clear epoxy (no carbon black) solved the problem.


Cheers,
ClaudiusB

 

[ClaudiusB]

you're exceeding the 80% rule using 14awg wire. 14 gauge wire is suited for a 15A breaker maximum and 12A at 80%. Using 12 gauge wire would put you where you need to be and would most likely solve your problem.

Every time you plug any device into your outlets you make sure you don't exceed the 80% rule?

14 AWG copper wire is rated for 20A but the overcurrent protection devices shall not exceed 15A.


Cheers,
ClaudiusB