automatic waterer - heater wires burned out

[WI Dan]

It's good this happened this time of year, instead of January!
I'm not real experienced with these units, so any tips would be appreciated.
Ritchie Omnifount 5
I think I can just re-wire the blown wire nut. Cut back the burnt wires and strip clean bare copper, then re-pack with a new wire nut.

 

[Janicholson]

That seems reasonable. I would do two additional things. The first is to use dielectric grease on the new wire nut, the second is to assess the amps in that circuit to be sure the element is not shorted causing excessive current in that circuit. Jim

 

[Phill Tibbetts]

I've seen problems like that before that was caused by the wire nut not being tightened tight enough when installed. Also seen it on a wired on plug end that the screw was not tightened tight enough. Just my 2 cents worth.

 

[showcrop]

That wire nut was only a wish when it was installed. It is too small for the number and size of wires. Get either a larger wire nut that is p to the job or use a split nut. Back in the day we kept a split nut or two on each truck for making connections when factory connections to heaters failed. The expansion/contraction that accompanies the heat and cool that accompanies the cycling of heat elements slowly loosens them up.

 

[miangus]

I use wire nuts with a sealer inside for this kind of connection. As Janicholson recommends, now would be a good time to inspect the heating element and if the heating element is shorted, I would replace the thermostat switch.

 

[WI Dan]

I use wire nuts with a sealer inside for this kind of connection. As Janicholson recommends, now would be a good time to inspect the heating element and if the heating element is shorted, I would replace the thermostat switch.

How can I tell if the heating element is shorted?
Do I use a multi-meter set to "ohm"s and verify continuity?

 

[WI Dan]

That seems reasonable. I would do two additional things. The first is to use dielectric grease on the new wire nut, the second is to assess the amps in that circuit to be sure the element is not shorted causing excessive current in that circuit. Jim

Good idea - I will use dielectric grease.

How do I check amps on the circuit?

 

[WI Dan]

That wire nut was only a wish when it was installed. It is too small for the number and size of wires. Get either a larger wire nut that is p to the job or use a split nut. Back in the day we kept a split nut or two on each truck for making connections when factory connections to heaters failed. The expansion/contraction that accompanies the heat and cool that accompanies the cycling of heat elements slowly loosens them up.

That's what I was thinking too. Your point about the heat/cold cycle is valid: this unit endures -30 temps all the way to 95.

I have to investigate what a "split nut" is.... I've never heard that.

 

[Jim.ME]

Split bolt connectors. They have covers to insulate them and you want good electrical tape like 3M's Super 33 or 88 grades.

 

[Jaden]

Make sure you replace any of the wires and/or connectors with a dull, crusty appearance. Scaly copper has higher resistance and will cause future failures.

 

[WI Dan]

Split bolt connectors. They have covers to insulate them and you want good electrical tape like 3M's Super 33 or 88 grades.

View attachment 134153

Got it, thanks!

 

[WI Dan]

Make sure you replace any of the wires and/or connectors with a dull, crusty appearance. Scaly copper has higher resistance and will cause future failures.

Yes, I plan to strip back to bare clean copper. I hope the wires are long enough.

 

[Janicholson]

Amps are checked with an AC amp meter Harbor freight has them:
Cen-Tech 400 Amp TRMS Auto-Ranging Digital Clamp Meter Typically $25
Jim

 

[miangus]

I have that meter and it has served me well I keep it in my farm truck. The kids got me a nice FLUKE but I hate to beat it around in the truck. I keep the HF meter in a Klien case, so I look like I know what I am doing. If you know the heater wattage you could check the ohms to see if its ok. Voltage squared divided by watts should get you close to what the ohms reading is.

 

[Pete in Holland MI]

If those wire nuts are in that position normally, that could be a problem. Guessing this is an outside installation. Wire nuts should always be installed so that they can't catch any water. Water gathering in the nut will cause corrosion, thus resistance in the connection. As others have said too, get the right size nuts for your group of wires.

 

[showcrop]

I just remembered another job that we did frequently to upgrade OEM was to replace common crimp-on terminals on heater contactors with high heat tungsten alloy contactors. Again, the cycling and heating-cooling would loosen the terminals, then the insulation would start to melt, sometimes on other wires in addition. Sometimes the fire dept. would be called.

 

[WI Dan]

I have that meter and it has served me well I keep it in my farm truck. The kids got me a nice FLUKE but I hate to beat it around in the truck. I keep the HF meter in a Klien case, so I look like I know what I am doing. If you know the heater wattage you could check the ohms to see if its ok. Voltage squared divided by watts should get you close to what the ohms reading is.

Thank you for this.

 

[WI Dan]

If those wire nuts are in that position normally, that could be a problem. Guessing this is an outside installation. Wire nuts should always be installed so that they can't catch any water. Water gathering in the nut will cause corrosion, thus resistance in the connection. As others have said too, get the right size nuts for your group of wires.

Good point. I'll try to point them upwards.
And slather with dielectric grease.