Almost an Electric Fire!

By luck I opened my version of a Kal clone to see something with the wiring and was shocked to see one of the legs of the 220 wire and terminal had cooked pretty solidly. It's on a 30 amp gfci, the elements have a selector switch so there is no way for the system to draw over 30 amps, 10 gauge wire. So, the only thing I can think is that the bond from the wire to the contactor had too much resistance causing the hot spot. The system has done around 15 batches without a hitch. I found no evidence that anywhere else in the system had overheated.

I only have a standard multimeter and it isn't sensitive enough to read ohms at a meaningful level so right now I'm guessing that the issue is a bad bond.

Thoughts on other causes that I'm over looking? For now I replaced the wire and terminal, cleaned up the screw and bonding surface to shiny metal and reinstalled.

View attachment ImageUploadedByHome Brew1428540038.733452.jpg

Yep - Looks like a bad crimp to me. What size of wire and how many amps?

Yep, I've had two of those. I assume the first one was from a poor crimp. The second one burned up a SSR, not sure what happened there.

In the future, all crimps get soldered.

I brew outdoors, so I don't worry about burning down the house. (I do a lot of internal electrical work, so there's always that )

What type of crimper did you use? I'd like to know what to be careful of when I buy tools for my build.

Also, a suggestion for all electric brewers: Inspect the inside of your control box, and all other high current connections, thoroughly after the first use for any sign of overheating. Then inspect periodically, say every 5 brew days.

Brew on

Thanks guys. 30 amp, and that is 10 gauge that cooked. Crimp looked solid, was still holding tight. I think I will solder it like passedpawn suggested to really get the bonding. Wish I could bring home one of the ohm meters they have at work and go over all my connections now.

Bensiff said:

Thanks guys. 30 amp, and that is 10 gauge that cooked. Crimp looked solid, was still holding tight. I think I will solder it like passedpawn suggested to really get the bonding. Wish I could bring home one of the ohm meters they have at work and go over all my connections now.

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They sell a reasonably good VOM at harbor freight for less that ten bucks - it'll work in a pinch. AWG 10 THHN wire shouldn't even get hot at 30 amps, so definitely the crimp. I use a pair of lineman pliers like this:



Good leverage with them - never had a problem with a crimp yet... (Knocking on wood)

I would also replace the contactor, looks like the corner may be damaged..
If not, I would at least replace the screw.. << Nevermind.. Re-Read..

jsprinceiii said:

I would also replace the contactor, looks like the corner may be damaged..
If not, I would at least replace the screw.. << Nevermind.. Re-Read..

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It was a used contactor off ebay, so that is in my thoughts still. However, I didn't see any damage other than surface contamination which got sanded and steel wooled to bright metal and maybe a few more inch pounds on the screw on the re-install.

Normally I can see the dimple made from the crimp on a terminal - and I don't see them on any of your crimps. It may be the picture, or it may be the style terminals you use vs. what I've used (or my eyes, haha), but my first thought was that it was a bad crimp, and that you may have a bunch of others too.

The screws on the contactor look like replacements/round head stove bolts..
While I agree about the crimp, I am also not convinced the screws were tightened
as well as they could be. Heat/Cool could have loosened the connection over time.

I would still recommend replacing the contactor..

because of the first post here I opened mine today and checked

brewing on Friday and thought it was worth a check

it was all good but never thought to check before this thread

OP thank you for the reminder

S_M

Some crimpers do not form a dimple when they crimp, they use a ratcheting mechanism to squeeze the terminal to a preset value by the mechanism. At least with that type all the crimps will be at the preset force when crimped.

With the lineman pliers it is up to you to gauge the force that you are applying to the crimp. I have used lineman pliers a lot and have always trying to make sure I have used the most force I can generate with my hand size/strength.

The ratcheting style are much better, but also more expensive, type of crimper.

TungstenBeer said:

Normally I can see the dimple made from the crimp on a terminal - and I don't see them on any of your crimps. It may be the picture, or it may be the style terminals you use vs. what I've used (or my eyes, haha), but my first thought was that it was a bad crimp, and that you may have a bunch of others too.

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I used the standard wire stripper/cutter/crimped combo widely available. Like every multi tool it does all things mediocre. No other wires showed any indication of trouble.

Bensiff said:

I used the standard wire stripper/cutter/crimped combo widely available. Like every multi tool it does all things mediocre. No other wires showed any indication of trouble.

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Take those POS multi tools and throw them away, get a crimper like the one in the pic above.

I would at the very least get a new screw, not any screw but the same material too. The old one was heated and will probably break or Shear off under the correct amount of torque.

If I were going to use that contractor, use these.
View attachment ImageUploadedByHome Brew1428600771.566423.jpg

That way you can get a good amount of torque on the wire and on the contractor.

trimixdiver1 said:

Take those POS multi tools and throw them away, get a crimper like the one in the pic above.

I would at the very least get a new screw, not any screw but the same material too. The old one was heated and will probably break or Shear off under the correct amount of torque.

If I were going to use that contractor, use these.
View attachment 269936

That way you can get a good amount of torque on the wire and on the contractor.

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Personally, I prefer this over crimp terminals..

Bensiff said:

I used the standard wire stripper/cutter/crimped combo widely available. Like every multi tool it does all things mediocre. No other wires showed any indication of trouble.

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Interesting. I use the same tool, hah. I guess these things just happen sometimes so it's good to check everything.

TungstenBeer said:

Interesting. I use the same tool, hah. I guess these things just happen sometimes so it's good to check everything.

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Yeah, at work we have multi-thousand dollar ohm meters to make sure the bonding and connections are good. At home, getting an ok ohm meter runs over a hundred dollars so the best most folks have to check are the basic units that don't read low enough accurately to really start showing where a problem might be...so its use the proper gauge equipment, crimp the snot out of it, and do some equipment checks to make sure everything is good.

Yup! I'm a pretty big guy and I put everything I have into each crimp, haha. It helps.

Usually insulated terminals require a ratcheting crimper with the proper die. I don't know how well they work, but those pliers aren't made for crimping insulated terminals.

If crimped properly the connection would only be degraded by soldering.

That looks like arcing to me, and not a "hot spot" as described. The arc probably is still there if you plug it in and fire it up, assuming you haven't messed with it too much.

I think this is why god created wire nuts and electrical tape. It is also why I cringe whenever I see posts of people making these rigs in wooden boxes.

Crimps are a real trouble spot. Most crimp connectors are a split connector instead of a full circle, and most crimping tools do little more than squeeze things together. The ones I use create a deep dimple, and I align that dimple with the split if I'm using a split crimp........it's difficult to find unsplit crimp connectors except in the aviation world. you are running a LOT of current through a poor connection. Solder is the obvious answer, and works great where there is no motion. Throw the stupid plastic insulator away......It does NOTHING except prevent you from seeing the crimp. If you don't use solder, at least use silicon dielectric grease.. and examine the crimp carefully to ensure you have good contact. The grease will prevent electrolysis which will cause failure. The connectors here look like crappy automotive connectors.


H.W.

TungstenBeer said:

Interesting. I use the same tool, hah. I guess these things just happen sometimes so it's good to check everything.

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Some's better than others...

Here's my favorite for the multi-tool..



Klein - I've got a few pair and they do a decent job also - but the lineman pliers are better at crimping.

Even while working on equipment for a Fortune 500 Aerospace company, I've never used ratcheting crimpers on run of the mill Red/Blue/Yellow wire terminals.

NO! Don't use those klein strippers as a crimper. Its bad news. The work great as cutters, and strippers, but everything on the handle side of the rivet is crap.

So instead of folks tripping over themselves figuring out how to afford a Greenlee punch, they should really be investing in better wiring equipment.

Those cheap multi tools (even Klein) are garbage for crimping anything greater than 12vdc in your car, even for 12vdc I would use a better crimper. The lugs I posted a pic to are a cheap way to ensure a good connection. No crimper involved, just a good screwdriver and some torque.

You all know what they say about opinions..

I'd trust those Kleins for up to 20 amp circuits.

jsmsmk said:

The ratcheting style are much better, but also more expensive, type of crimper.

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X2 on the ratcheting crimper. It's the only one that will give consistent quality crimps. Any other method is a shot in the dark. As previously mentioned, they are not inexpensive but how many crimps in a control panel do you want to chase later?

http://www.amazon.com/dp/B000NI3EMK/?tag=skimlinks_replacement-20

For reliable crimp connections that don't fail/overheat, the right technique, proper selection of materials and attention to detail is everything.

I shake my head when I look at someone else's work and see they have attempted to use crimp connectors on solid conductor wire.

In circuits where it matters, use good quality name brand crimp connectors, not the ones that come in the HF variety box.

If you cut or nick strands in the wire you are crimping, cut it back and start over.

After you crimp on a terminal, grab the wire in one hand, the terminal in the other, and pull it HARD. You will catch bad/loose crimps this way.

When it really matters, I will crimp the lug to the wire and solder it too.

Use a good crimping tool.

Do a few practice crimps if you have never done them before.

processhead said:

I shake my head when I look at someone else's work and see they have attempted to use crimp connectors on solid conductor wire.

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I fully agree with this, but generally speaking there seems to be some disagreement about solid core wire. For me, when I look at a proper crimp with stranded wire, I don't see any way that a solid wire crimp could be crimped properly.

My friend continuously offers his romex 14/2 (solid) to use the interior wires for the couple control panels I'm working on, and for some reason he's always miffed as to why I'd rather spend the money for stranded wire instead. I will use it when the connection I'm making requires no crimp, however (although I never use the bare ground wire).

TungstenBeer said:

I fully agree with this, but generally speaking there seems to be some disagreement about solid core wire. For me, when I look at a proper crimp with stranded wire, I don't see any way that a solid wire crimp could be crimped properly.

My friend continuously offers his romex 14/2 (solid) to use the interior wires for the couple control panels I'm working on, and for some reason he's always miffed as to why I'd rather spend the money for stranded wire instead. I will use it when the connection I'm making requires no crimp, however (although I never use the bare ground wire).

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Don't crimp on solid core wire. Doesn't make low-ohm connections and you'll probably end up letting the smoke out of your brewery.

passedpawn said:

Don't crimp on solid core wire. Doesn't make low-ohm connections and you'll probably end up letting the smoke out of your brewery.

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Like I said - I don't.

TungstenBeer said:

Like I said - I don't.

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Got it. I quoted you, but I was really just agreeing.

TungstenBeer said:

I fully agree with this, but generally speaking there seems to be some disagreement about solid core wire. For me, when I look at a proper crimp with stranded wire, I don't see any way that a solid wire crimp could be crimped properly.



My friend continuously offers his romex 14/2 (solid) to use the interior wires for the couple control panels I'm working on, and for some reason he's always miffed as to why I'd rather spend the money for stranded wire instead. I will use it when the connection I'm making requires no crimp, however (although I never use the bare ground wire).

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Easy, look up the crimp terminal specs, if it's rated for solid you good to go. If you can't find the specs, don't use the connector.

Got a brew in this weekend with the repair done, yes crimped stranded, yes in cheap Amazon connectors, yes with my crappy crimp tool. Yes I gave it a solid visual inspection and a firm tug to make sure it was secure. I shut the system down a few times mid brew and checked the wire to make sure it wasn't heating up. All was well with the world, and will be more so in a year or so when the lambic I brewed starts getting blended.

Bensiff said:

Got a brew in this weekend with the repair done, yes crimped stranded, yes in cheap Amazon connectors, yes with my crappy crimp tool. Yes I gave it a solid visual inspection and a firm tug to make sure it was secure. I shut the system down a few times mid brew and checked the wire to make sure it wasn't heating up. All was well with the world, and will be more so in a year or so when the lambic I brewed starts getting blended.

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Your the one who had an electrical fire and asked what could be done to prevent it. We told you and now you give us attitude? Glad to see you didn't have another issue. Good luck. Bye

Bensiff said:

Got a brew in this weekend with the repair done, yes crimped stranded, yes in cheap Amazon connectors, yes with my crappy crimp tool. Yes I gave it a solid visual inspection and a firm tug to make sure it was secure. I shut the system down a few times mid brew and checked the wire to make sure it wasn't heating up. All was well with the world, and will be more so in a year or so when the lambic I brewed starts getting blended.

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Here's what's going to likely happen:

The crimp may feel secure now, but as it heats and cools during cycling, it will (via expansion and contraction) get looser, which will lead to the connection developing higher resistance. This will continue to cycle until you're back where you started, if it doesn't burn your control panel.

trimixdiver1 said:

Your the one who had an electrical fire and asked what could be done to prevent it. We told you and now you give us attitude? Glad to see you didn't have another issue. Good luck. Bye

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I only asked for another opinion about the cause. That wasn't attitude, perhaps a touch of sarcasm given the page of discussion about crimping solid core wire. Yes, I know I didn't use ideal tools as you all recommended. But they can still get the job done if you pay close attention to what you are doing and inspect the job before throwing it into service.

Bensiff said:

I only asked for another opinion about the cause. That wasn't attitude, perhaps a touch of sarcasm given the page of discussion about crimping solid core wire. Yes, I know I didn't use ideal tools as you all recommended. But they can still get the job done if you pay close attention to what you are doing and inspect the job before throwing it into service.

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Like you paid close attention to the crimp that failed right?

trimixdiver1 said:

Like you paid close attention to the crimp that failed right?

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Cut it out. You give advice here, people don't have to follow it.

passedpawn said:

Cut it out. You give advice here, people don't have to follow it.

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Ok