Failed Element Scare and Questions

Hey everyone. So tonight was my first test with a recirculating eBIAB system. It's a 120V setup with a 1500W element. During the mash, the element kicked on and my GFCI tripped.

I scratched my head, shut everything down, fired it back up, and it tripped again (in retrospect, maybe not the best idea). My kettle is actually induction capable, so I just let the mash finish and moved the pot onto my old induction top to boil and finish up.

After the brew I pulled out my multimeter and tested the continuity of the pot to ground. Then I checked the continuity of the element leads to ground. Complete circuits everywhere. I dissembled everything to see what happened. Here's what I found.



It almost looks like something inside the element burst through the element housing wall. The whole thing lost isolation and went hot. So here are my questions.

1) What happened here? Did the element just fail catastrophically? Has anyone seen this type of thing before? This was my first test with a pump and whatnot, but I don't really think I did anything differently. I've done at least 12 brews with the kettle, all of which were pretty uneventful except one instance of mild scorching.

2) Shouldn't the breaker have tripped and not the GFCI? I've read that a huge pull of current can fool them into tripping, but there wasn't a leak, just a short. Or am I misunderstanding something about GFCIs? At any rate, I'm glad one of the safety systems stepped in.

3) Should I worry about the beer? Is there anything to fear from the damaged housing floating in my beer?

Anyway, I'm no worse for the wear and super glad that the pot was grounded and I was running with the standard protections in place . Be careful out there, everyone. Brew on.

Did you dry-fire it at any time?

iijakii said:

Did you dry-fire it at any time?

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Once, to remove some of the scorched crud. That was 5 or 6 brews ago

Bingo

GFCI's will trip before a standard circuit breaker does once it senses a ground fault (short to ground). Breakers do not trip with a ground fault and trip when there is a high current load past it's rated current.

That's why standard breakers do not trip with a ground fault because most of the times, it won't draw more current than it's rated at but the whole circuit is electrified and poses an electrocution danger, that's why GFCI's were developed.

EDIT: Standard circuit breakers can trip with a ground fault if the amperage draw is high but a GFCI circuit will act faster than a standard breaker, within milliseconds, since it's not looking for high amp draw.

Saboral said:

Bingo

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I'm willing to accept that this may have been a contributing factor. However, it seems like a not uncommon practice to dry fire for a few seconds to remove charred on material from the element.

I'm guessing there is no standard behavior when an element fails. In this case the housing cracked and lit the whole pot off? Do elements also fail by causing the connection to just break permanently (unable to turn on at all)?

dmcman73 said:

GFCI's will trip before a standard circuit breaker does once it senses a ground fault (short to ground). Breakers do not trip with a ground fault and trip when there is a high current load past it's rated current.

That's why standard breakers do not trip with a ground fault because most of the times, it won't draw more current than it's rated at but the whole circuit is electrified and poses an electrocution danger, that's why GFCI's were developed.

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Makes sense. I guess I was thinking in this case the current in and current out should be identical since there was no other path to ground (me) touching the pot at the time. But I guess a GFCI would be far less useful if it didn't trip when a device failed to the ground wire.

If (and I have no intention of ever doing this), a grounded element failed without GFCI protection, wouldn't it be possible that the short would pull enough current to overload the breaker? Also, if someone touched a hot but grounded pot, would the wire ground offer some protection to that individual?

I know these sound like basic questions, I'm just running through all the hypotheticals from last night to make sure I understand all the levels of failure/safety in the system.

hannibalmdq said:

I'm willing to accept that this may have been a contributing factor. However, it seems like a not uncommon practice to dry fire for a few seconds to remove charred on material from the element.

I'm guessing there is no standard behavior when an element fails. In this case the housing cracked and lit the whole pot off? Do elements also fail by causing the connection to just break permanently (unable to turn on at all)?

Click to expand...

I had a MWD or HWD short little element like yours fail in exactly the same way when I dry-fired it. Although it failed immediately, not brews later like you say. I didn't bother breaking into it, but what I think happened is part of it got too hot and the insides cracked causing a loose connection somewhere along? No idea. Mine looked fine from the outside though unlike yours.

Dry-firing to burn stuff off is only acceptable on the ULWD wavy elements it seems. Yours cannot handle that.

iijakii said:

I had a MWD or HWD short little element like yours fail in exactly the same way when I dry-fired it. Although it failed immediately, not brews later like you say. I didn't bother breaking into it, but what I think happened is part of it got too hot and the insides cracked causing a loose connection somewhere along? No idea. Mine looked fine from the outside though unlike yours.

Dry-firing to burn stuff off is only acceptable on the ULWD wavy elements it seems. Yours cannot handle that.

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Yea, I don't think I'd dry-fire an element that wasn't ULWD. Well, actually I probably would, to be honest, but I wouldn't recommend it to others

hannibalmdq said:

Makes sense. I guess I was thinking in this case the current in and current out should be identical since there was no other path to ground (me) touching the pot at the time. But I guess a GFCI would be far less useful if it didn't trip when a device failed to the ground wire.

If (and I have no intention of ever doing this), a grounded element failed without GFCI protection, wouldn't it be possible that the short would pull enough current to overload the breaker? Also, if someone touched a hot but grounded pot, would the wire ground offer some protection to that individual?

I know these sound like basic questions, I'm just running through all the hypotheticals from last night to make sure I understand all the levels of failure/safety in the system.

Click to expand...

If your kettle or RIMS tube (or where ever the element was installed) was properly grounded then the instant that element went on, some electricity would have been sensed on the ground which would instantly cause the GFCI to trip, that's how it was designed.

This may answer your question better: http://home.howstuffworks.com/question117.htm

Standard breakers look for high current draw and may not act as fast to trip
GFCI's do not look for high current flow and looks for any "imbalance" of current between the Hot and Neutral leads, up to milliamps and will trip if it senses any.

hannibalmdq said:

I'm willing to accept that this may have been a contributing factor. However, it seems like a not uncommon practice to dry fire for a few seconds to remove charred on material from the element.

I'm guessing there is no standard behavior when an element fails. In this case the housing cracked and lit the whole pot off? Do elements also fail by causing the connection to just break permanently (unable to turn on at all)?

Click to expand...

not uncommon for ULWD elements that is a regular density element which can be damaged quickly. there shouldnt be charred buildup on the element in the first place... thats why regular higher watt density elements are not a good choice.

Keep in mind that GFI does not work by sensing current to the ground. They work by sensing if there's any current difference between the current-carrying wires.

StMarcos said:

Keep in mind that GFI does not work by sensing current to the ground. They work by sensing if there's any current difference between the current-carrying wires.

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@dmcman73 did get it more rigorously correct in the last paragraph. Although to be fair, any imbalance between hot and neutral would most likely be due to current to ground.

Brew on

Thanks, everyone. I actually acquired a 1500W ULWD element about a month ago but hadn't installed it yet. I'm going to swap that in when I reassemble the housing.

I'm feeling much better about the whole series of events. While the element going hot was concerning, I'm glad there was a lot of guidance on here regarding the proper way to wire these things up, and very pleased that the fail-safes did their job (kettle ground tripped the GFCI before I had a chance to trip the GFCI).

Brew on, everyone. And brew safely, too.

doug293cz said:

@dmcman73 did get it more rigorously correct in the last paragraph. Although to be fair, any imbalance between hot and neutral would most likely be due to current to ground.

Brew on

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Yup, the current has to go somewhere, it's either going through a person that is grounded or to a ground, it's just one way the GFCI monitors it.

Alright, this is getting a little worrisome. My new 1500W ULWD element failed today (3rd brew with it). I was doing back to back brews. The first went off super smoothly. I love recirculating eBIAB. Consistent temps, one vessel, it's just great. Cleaned up, filled my kettle back up and dialed in the strike temp.

Somewhere between the 15 and 20 minute mark of the second mash my element shorted out. I checked it at 15 minutes and it was humming along just fine. I went inside to do something for my son, come back out, and the GFCI's tripped. I switched over to my induction top, and continue the brew day fairly uneventfully. Took a little more babysitting to make sure the induction top would kick on when the temp dipped, but all in all, it went smoothly.

So I check the element, and it's not the same issue as last time. Instead, there's no continuity between the neutral and the hot terminals on the element. Something has broke inside the element itself. What's going on here? Am I just not meant to have a eBIAB rig? Do these cheap water heater elements not like being run all day? I've attached a few pictures of the element, but there's really nothing of note I can see. I'm positive the wiring isn't the issue. I rigged up an element guard by bending a pressure canner aluminum bottom into a form that covers the element and dip tube, but there's plenty of clearance around both fixtures. Mostly it just keeps the bag off things during the mash. Could that be causing an issue? Could this just be bad luck?

I wish that was an ULWD element.

Bobby_M said:

I wish that was an ULWD element.

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The element was sold as ulwd (http://www.amazon.com/dp/B000KKVZUO/?tag=skimlinks_replacement-20) but you appear to be correct. Other reviewers complained about that. Still, this is two element failures within 4 brews of each other. I'm really curious if this is just happenstance or if I'm doing something to cause it.

A simple open fault in the element (no continuity between hot and neutral) shouldn't trip the GFCI. Something else must have happened to cause the trip.

Brew on

I have blown 3 elements. Dry fire for a second and you are in trouble. Fortunately they are cheap.

doug293cz said:

A simple open fault in the element (no continuity between hot and neutral) shouldn't trip the GFCI. Something else must have happened to cause the trip.

Brew on

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I wasn't there for whatever the event was that tripped the gfci. I'm in agreement the lack of connectivity I saw when I inspected the kettle after brew day was a symptom, not the cause. That does beg the question I'm asking. What could've happened?

What I think is happening is that you're recirculating faster than your bag can flow the wort out so you occasionally evacuate all the wort away from the element. One way to monitor this situation is to install a sight glass down low. You'll see the liquid level in the sight drop dramatically if this situation happens. I've done it once but luckily I was running a ripple element at 1300 watts so it was beyond ULWD and a dry fire doesn't hurt it.

Bobby_M said:

What I think is happening is that you're recirculating faster than your bag can flow the wort out so you occasionally evacuate all the wort away from the element. One way to monitor this situation is to install a sight glass down low. You'll see the liquid level in the sight drop dramatically if this situation happens. I've done it once but luckily I was running a ripple element at 1300 watts so it was beyond ULWD and a dry fire doesn't hurt it.

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Exactly my thoughts. If recirculation is too rapid for the grain bed under the bag and "false bottom," that element could rapidly heat to failure. This is part of the reason I'm hesitant to go with recirculating eBIAB. It's too bad there isn't a simple way to install a thermostat to prevent the heating element from going significantly over boil temps.

craigmw said:

Exactly my thoughts. If recirculation is too rapid for the grain bed under the bag and "false bottom," that element could rapidly heat to failure. This is part of the reason I'm hesitant to go with recirculating eBIAB. It's too bad there isn't a simple way to install a thermostat to prevent the heating element from going significantly over boil temps.

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I thought a level switch would solve this problem, but it seems like most kettles wouldn't have room under the false bottom to install one above the element level. But what about this....

Put an elbow on the pump suction, inside the kettle, and point it up so that it extends above the elevation of the heating elements. Then add a low flow switch on the pump discharge that kills the elements and pump.

Only con I see is that you can't completely empty your boil kettle because of the tall suction. Maybe if you had a rotating suction like one of those SS Brewtech fermenters that would fix the problem.

Or you could just keep it simple. Establish good recirculation, keeping the flow rate low, before turning on the element(s).

oakbarn said:

I have blown 3 elements. Dry fire for a second and you are in trouble. Fortunately they are cheap.

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and a good ULWD can be dry fired for much longer, plus it has the added advantage of not causing possible scorching issues.. they only cost a few $$ more than the one the OP uses now.

craigmw said:

Exactly my thoughts. If recirculation is too rapid for the grain bed under the bag and "false bottom," that element could rapidly heat to failure. This is part of the reason I'm hesitant to go with recirculating eBIAB. It's too bad there isn't a simple way to install a thermostat to prevent the heating element from going significantly over boil temps.

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a lower flow pump such as the 24 or 12v dc tan food grade pumps which only pump between 2-3 gallons per minute would be a cost effective way to prevent this issue as well... the lower flow wont negatively impact anything, Ive been using these pumps for over 2 years now.

and they do sell elements with thermocouples built in... I have one I was using in my rims for a while but it never got any hotter than the setpoint on the surface which actually slowed down performance a lot... it was a stainless cartridge heater, they are easy to mount in a compression fitting.

Thank you everyone, for giving me some insight into what may be happening. I ordered a 12inch 1500W SS element which should drastically reduce the watt density.

Also, Bobby. it's interesting you mentioned the sightglass could provide a good indicator that the pump was pulling too much away from the bottom. I have a sight glass and I've seen this happen a few times over my last several brews. I'll have 6 gallons in the pot for the mash but the sight glass would dip down to 2 gallons. I thought it may be the bag doing something funny like blocking the dip tube intake, it had not occurred to me this could be caused by the pump pulling so hard below the grain line.

I've been using one of the smaller 12V DC pumps. I do have a spare ball-valve I could use to regulate the output flow. I'll rebuild everything and give it another whirl in a week or two. Hopefully between those two adjustment, I'll have better luck.

Oh for sure you need to regulate the pump flow down. I've found that limiting to a quart per minute is enough to flow the bag just fine.

Bobby_M said:

Oh for sure you need to regulate the pump flow down. I've found that limiting to a quart per minute is enough to flow the bag just fine.

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Thats interesting ... I dont throttle mine down but rather start it really low and ramp it up over the course of the first minute or so to prevent the false bottom/ screen setup from plugging. at that point the pump is at 100%
I use a flowmeter with my 16 gallon BC mashtun and a 24v dc pump and when doing 5 or 10 gallon mash recirculations I recirculate between 1.6 and 2.0 gallons per minute through the flowmeter(depending or grain restriction) with no issues... I use a false bottom with a bazooka tube and finer stainless braided line inside that for filtering under the false bottom... I never have any cavitation issues and the pump doesnt suck dry at all... (i do use a rims)

I suppose it's possible to flow faster without problems but I think the goal is to keep the mash temp consistent without having to babysit just in case of pumping the bottom end dry. Disclaimer, I only have experience with larger 1/20th HP pumps and not the DC pumps.