Check your wiring!

[NormandieStill]

So I was setting up for a big run tomorrow and noticed that the cable grommet on the back of the heating element was loose. I thought I'd quickly pull the cover off and tighten it up, and was faced with this:

Turns out the nuts that held the two spade connectors in place had come loose. While nothing had shorted, current was clearly not flowing nicely and looking at the wires and the insulation on the spade connectors it had clearly got quite hot. For the record I had been running 20A through this just 2 days ago.

So my advice for the crowd, at least for those of you not intentionally playing with fire, from time-to-time, open up your covers and check that everything is tightened up properly. A bit like checking the tightness of your wheel nuts. There's probably nothing to worry about, but you might just catch something before the wiring catches fire and starts an electrical fire next to your pot of boiling alcohol!

[Wildcats]

Thanks for sharing this. And good advice. All ways good to keep up with preventative maintenance. Good find before it burnt thru the wires and shorted out .

Have fun and stay.

[elbono]

What a pita. I really like that type of element connection but they're difficult to assemble/disassemble.

I'm pretty sure Normandie knows all this but for non electrical types:

Connections are most likely to get loose the first few uses so check/retorque them often after putting them together, just periodically after that.

When this happens the copper will be oxidized you have to strip back to bright conductor. I'll bet just putting your hand on the cord where it came out of the element can would have shown something was wrong.

[ecir54]

no doubt a hot spot. use better stakon connectors and a quality crimping tool.

[Chucker]

I wouldn’t use crimp on ring or fork connectors at all. Even if secure, you’re reducing to a very minimal conductor area from 10-12 ga wire. It is very likely to have quite a bit more resistance to a fairly high load potential.
Crimp-on ring terminals that are rated for that kind of load are pretty substantially sized; think those at the end of a cord for an electric dryer or kitchen range. You’d be pretty hard pressed to get those under the cap of an element.

[elbono]

no doubt a hot spot. use better stakon connectors and a quality crimping tool.

I like ring terminals and a good crimp tool is a must but I think Normandie is savvy enough to figure out what was loose that started the melting. Once it starts everything gets hot.

Terminals usually carry a current rating at least equal to the wires they fit. I use a 10 awg cord on my element. It has 105 strands of 30 awg in the conductor. Good luck hooking that up without some sort of crimp.

IDK what insulation is used in cables in Europe but In the US it's usually PVC rated for 105C
That was way past 105.

[juana_b]

Merci beaucoup NormandieStill.
My last stripping run, after shutdown I noticed the heater cord was warm.
This post reminded me to investigate. I found this:

It should look like this:

In the first pic the failure of the heater post connection to the screw terminal can be seen.

Going forward, I'm soldering my crimps, though this wasn't a connection failure but rather a component failure.


Edit: upon further inspection of my new replacement heater, I found that one of the heater post connections to the screw terminal has broken away. If I would have hooked it up and turned it on, I would have had the same issue again. Just dug out my big soldering iron, hopefully I'll get some time tomorrow. Don't know if I'll be able to get a good pic of the break though. If possible I'll post it.

[shadylane]

I prefer to solder connectors to the wires instead of using a crimp.
That and use high temp connectors, star washers and antioxidant paste.

[ecir54]

both solder and crimp connectors can work if done properly. with the proper crimping tool i prefer to go that route if don't have the right tool soldering will work fine if you don't create a cold joint and allow it to cool naturally without blowing on it.

[Yummyrum]

…….and antioxidant paste.

Never heard of that before Shady .How does that work

[juana_b]

…….and antioxidant paste.

Never heard of that before Shady .How does that work

Shmoo that keeps oxy and h2o out.
KY for circuits. I'm sure someone else with more knowledge will chime in.

[elbono]

…….and antioxidant paste.

Never heard of that before Shady .How does that work

In the US it's called Noalox. Usually used on aluminum conductors but can be used on copper. It's conductive so don't schmooze it everywhere, just on the connection.

I'll be picking up Noalox and star washers on the next trip to the big box store.

[Yummyrum]

Oh thanks Juana and Elbono

Sure similar stuff is available down under . Just never heard of it before . Good to know its conductive . That’s important info ….So just apply directly to just the connections only .

Filling the entire element guard to be sure to be sure , sounds like potential Arcy sparky circuit breaker bedlam

[Deplorable]

This really can't be overstated.
Shortly after converting to electric, after a day of boiling two back-to-back charges of water at 100% power I found my cord melted at one of the prongs on the element.
When I tore it down I found that one of the connections had worked loose.
While replacing the connector I tinned the ends of the wires, and flattened them a bit before reseating them in the new plug end to ensure the set screw could get a solid bite on the wire.

[elbono]

I tinned the ends of the wires

If you are using a twist lock type element with a female plug, the instructions for the plug will say to NOT tin the wires. Supposedly since the solder is soft it will make it more likely to loosen.

Yeah, I know, the first step is throw away the instructions. I'm one of the weird people that read them.

[Deplorable]

I tinned the ends of the wires

If you are using a twist lock type element with a female plug, the instructions for the plug will say to NOT tin the wires. Supposedly since the solder is soft it will make it more likely to loosen.

Yeah, I know, the first step is throw away the instructions. I'm one of the weird people that read them.

Yeah, reading hte instructions was got me the melted connector. Ive checked it regularly since the repair, and it's solid as hell.

[PLAYMP]

I had a similar experience with my Dernord ripple element. I found the plastic cable grip it came with wasn’t perfect and I handled the cable enough that I would often check the connections and in some cases it was clear some contacts had come loose and a lot of heat had built up where you refer to. For a water heater or something where the element doesn’t move very much it’s probably fine but it’s a risk for us home distillers who set up and tear down their stills in between runs, I do at least.

I just completed an upgrade of my electrical setup, including the element and went with this version with a male twist lock plug on it:

DERNORD 240V 5500W Tri-clamp Ripple Heating Element Stainless Steel Immersion Water Heater with 3-Wire Electrical Locking Plug (2 Inch Tri clamp) https://a.co/d/e3Uzb4c

It’s a few extra bucks but the peace of mind and the hassle of trying to bend my wires and spade connectors just the right way is worth it.

[ecir54]

^^^ have upgraded to one like that too when they became available, even made my own version before they were offered.

never been a fan of screw terminal on these heaters and have had different approaches over the years. Notice in pic a ring terminal can be made out of solid core copper wire that will be better than any stakon connector. You could even use them with a home made copper coupling to crimp or solder it to your wire creating an all copper connection.

[Demy]

I believe the looseness is due to the heating/cooling cycles...it is good practice to check often.

[ecir54]

agree with that Demy expansion contraction

digging in my bin tonight and came across some spare home made connectors i forgot i had.

[Yummyrum]

Solid wire is actually a bad choice . It doesn’t flatten like multi-strand wire does and so the contact area is relatively small . This causes a higher resistance between the wire and terminal resulting in localised heating .

Multi-strand wire will “squish” when the terminal is tightened creating a larger area in contact with the terminal . This results in a much lower contact resistance and much less heating in the contact area

[ecir54]

at work we do heat scans once a year at the property i work at. in my experience re torquing is more common with stranded wire as opposed to solid core. normandiestill is right check your wiring, both type of connections have the chance to loosen over their usage due to expansion and contraction.

[Deplorable]

Always check your wiring, never leave a running still unattended, and keep a fire extinguisher within reach.
While stripping my CROW bourbon today, I'm putzing around in the garage when I smell burning plastic.
I turned around and saw smoke coming from my L6-30 plug at the element.
Killed power at the controller and unplugged from the wall.

A quick trip to the hardware store, and in 30 minutes I'm up and running again.

[Wildcats]

WOW fried plug!! Bet that CROW is gonna be fire though! Glad it all turned out good.

[Saltbush Bill]

never leave a running still unattended, and keep a fire extinguisher within reach.

Good advice and a damn good reminder of why we never take our eyes off of a still. If they are going to do it , it is always at that moment when you've got your back turned.
Murphy Law says it will be so.

[Demy]

Excellent spade (or similar) connectors can be made by using a flattened and shaped copper tube...often it will be better than a common commercial connector.