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Damage to Dernord Heating Element
I was heating some water using a Dernord 5500W heating element. When I shut down I noticed that the extension cord TwistLok connection was pretty warm. I let it cool down, checked the connections to the element and this is what I discovered. This is 10 AWG cable by the way.
All of the connections are still tight and the wires are still tight within the crimps. By the way, that white neutral line is NOT connected to anything on either end. I taped both ends just to eliminate that as a variable though.I opened the connected TwistLok and saw absolutely no damage. I was able to tighten a couple of the connections just a little, but it’s hard to tell if that’s the cause or if I just exerted more force today than when I originally tightened them. I can’t determine if they loosened up over time or not. I assume that if those connections were loose enough to cause an issue, perhaps those connections would have melted. A year or two ago I recall a similar thread here. Someone had some connections melt and recommended that everyone check their connections occasionally to reduce the potential for similar issues. Is it reasonable to assume that the element is what failed because that’s the part that melted or is it possible that the cause could be further down the line (other connections)?4″ VM Build
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18 Replies
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8 GA is the min I’d use and only if the run was 6ft or less. Longer and you’d need 6 ga.Either way, that sucks man… heavy gauge cables aren’t cheapThere are two types of people in this world.1. Those that can extrapolate from incomplete information.
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Most everywhere I’ve seen, sources say for 30 amps, you’ll need a wire gauge of 10. I know larger cable is safer, but I just went with what is recommended rather than smaller cable.4″ VM Build
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I ordered an identical element.I checked every other connection down the line accept for within the wall receptacle (because it’s a pain in the ass to access) and everything looks just fine. I snugged up each connection just to be thorough. I have another identical element here so I’ll heat up a batch of water right now. I’ll be monitoring the temp of the cable & plugs as I go and see what happens. Afterwards I’ll open up the element guard and see if anything looks over-heated.4″ VM Build
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Yeah 10 should have been safe as long as the run wasnt too long. How long were your cords and far to the panel?This chart has never let me down
There are two types of people in this world.1. Those that can extrapolate from incomplete information.
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10 Gage is plenty big for a 22amp load.Bigger wires are needed if the wires are long due to voltage drop. Having long wires won’t make the wire get hotter, it will actually do the opposite.Because the voltage drop decreases the current.
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It’s about 45′ long overall from the breaker to the element itself. I know 8 gauge is larger, technically better, but I just went with what everything I’ve found recommended.
I feel a slight amount of warmth at the first TwistLok plug on the end of the 6′ cable connected to the element. I disconnected it and the 2 power prongs are very warm, but not hot enough to even burn my lip. One prong is noticeably warmer than the other. Keeping an eye on it every few minutes.4″ VM Build
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Heat buildup due to resistance of a poor connection causes heat. Then the heat causes corrosion and an even worst connection.Using oversized wires wouldn’t help, it can even cause problems with having the right sized connectors.
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Your crimp terminals need to be done differently. They are causing the heat build up.1) Ensure no wire fibre has been cut or broken when stripped.2) For non coated/non insulated connectors use a non insulated crimper. Not the one with the coloured dots. It is different than for insulated connectors. This is an important step needed to reduce resistance and heat build up.3) Cover the connection with heat shrink. The heat shrink should have “hot glue” inside the tube. This process reinforces the wire as well as provides some insulation.See this video for making proper crimp terminals. “What harms us is to persist in self deceit and ignorance”Marcus AureliusI’m not an alcoholic! I’m a drunk. Alcoholics go to meetings!
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Something like this works good for high temp connections. https://www.supplyhouse.com/DiversiTech … 2ede8f3b92
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I was the one warning about checking connectors. What shadylane said about corrosion seems likely. If you are brave enough to do it (some folks really don’t like electricity) set your kettle up with enough water to cover the element and remove the cover. Then power it up and with a multimeter, measure the voltage at the socket and at the element (assuming your controller is wide open or bypassed if you can). This should show whether you’re getting a voltage drop which will let you know if it’s likely to be the cable.I don’t know about US plugs, but I know that the standard EU plugs are rated to 16A but most should not have more than 11A pulled continuously and electric car charge cables often default to 8A unless using a special socket. Personally, my future distilling shed will be wired to a 32A CEEform connector as it will definitely handle the current.”I have a potstill that smears like a fresh plowed coon on the highway” – JimboA little spoon feeding *For New & Novice Distillers
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Thanks for that video! I’ll be sure to cut all connections and do them properly. I didn’t know any of the basics of crimping connections.4″ VM Build
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Do you think these ring terminals would be adequate? I have two controllers, at least 3 extension cords and other miscellaneous connections to redo so I might as well buy a good number of them. I’ll also eventually have to check the wall receptacle too.4″ VM Build
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Can’t say for sure if that’s the exact connector needed but it’s the right type although the 1/4″ hole looks too big. Measure the screw dia. and have the hole in the ring match.A good source for hightemp connectors is old electric stoves and hot water heaters.The heater has a pair of readymade, element to thermostat wires.
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I’d only use the high temp style connectors to connect to the hot elements.All the other connections don’t need it.Another option is to form the wire into a ring, then tin it with solder.It wouldn’t meet codes, but it’s works better than crimping.
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I’d only use the high temp style connectors to connect to the hot elements.All the other connections don’t need it.Another option is to form the wire into a ring, then tin it with solder.It wouldn’t meet codes, but it’s works better than crimping.Oh got it. Duhhhhh. I don’t mind getting the proper connectors for the elements. I’ll also replace the other connectors with the appropriate rated ring terminals and crimp them properly this time.It’s odd that this element and my other two elements have lasted over the years if the issue was these crimp connectors. My other element’s connections appear just fine. Still I’ll fix them.4″ VM Build
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Hi Salt .You questioned if anything upstream of the element can cause the problem at the element end ?Short answer is no . Any poor connection upstream will have it’s own localised meltdown . And to be honest, I think your connections at the element were done OK . When the terminal , its crimping or connection is the problem , then that is the source of heat . The terminals and the insulation on the wires all get’s cooked . …. Like all plastic turns almost black and brittle .Your wire insulation looks perfectly fine . The terminals aren’t discoloured . I suspect the termination of the element wires to the brass terminal straps ( inside the element) was poorly done and the heating that caused the melting was from the internals of the element not from your connections .Having said that , I would as suggested , use ring terminals as opposed to the split ones you used as they have a much better surface contact area . Greater surface contact area means lower resistance and less localised heating .My recommended goto .wiki/index.ph … ion_Theory
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That makes perfect sense. After seeing that part melted I was questioning everything.4″ VM Build
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I’ve had a similar issue in the past. I assumed it to be an issue with the connection. But I could see the arc THROUGH the wall of stainless element guard/housing before I immediately depowered it.
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