Heated water bowls and extension cords

[SMA]

Quote:
Electrical question...some of the bowls I've seen use only around 50 watts.
So is it any different than plugging a light bulb into an extension cord? Or are we talking apples and oranges ?

Thanks

 

[RocketDad]

Watts is watts. I have overheated extension cords with an air compressor, and I can feel heat in the cord when I'm running 2 space heaters and an oil-filled radiator at the same time trying to warm my trailer/office in the yard. But never enough heat to cause a fire. I frequently check them by hand, and turn off heat as soon as I can.

The risk with lightbulbs is failure mode. If the envelope breaks, the filament breaks, but the wires that hold the filament are still "hot." If they come into contact with a conductor, they can spark, and the short circuit can over heat the cord. Probably pop the circuit breaker before anything too bad happens, but still.

The failure mode for a manufactured heater is just failure. The components are contained.

50 Watts will not overheat a cord. You could just about run 50 watts through a wet kite string safely. (please don't try this)

The real problem is when people use a 16/3 cord, plug a cube tap or power strip into it, and proceed to plug every hole with 1500 watt heaters. Then walk away, or go to bed. The cords in my trailer are 12/3 and 10/3 (contractor grade - very pricey) and the heat happens at the connections, where the plugs are the highest resistance in the line. I turn things off even when I go inside to get a cup of coffee.

 

[Momo]

Here's another angle on the fire hazard possibility: I wouldn't be particularly worried about a heavy duty short extension cord except that the last thing you want is a fire developing against the side of your house. It's one of those scenarios that have a low risk of actually happening but a huge risk of resulting damage if it does happen. If a fire were to start in your little setup, fueled by the hay bales against the house, the fire is likely to extend up the exterior wall to the soffits and into the attic in no time. Could be catastrophic. You never want to have fuels against the house that will produce direct flame impingement on the soffit.

 

[Bellasmom]

When we read that warning on ours we determined that it was more to prevent dogs from chewing on a cord more than anything else. Since the cord itself is wrapped in chew deterrent wire. The wattage isn't any higher than running the amount of Christmas lights that we have.

 

[20tundra]

I use a 50 ft heavy duty outdoor extension cord which runs a light on a timer and a water heater made from a cookie tin and light bulb. I've been using a 40 watt bulb which worked will until the temps dropped to 8 degrees last night and I got a layer of ice on top. I'm going to try going to a 60 or 80 watt tonight and see if that helps.

 

[vicki2x2]

We use ours with extension cords, we have to, as the coops are set in different places in the yard so the extension cords run out to them. We have done this for two winters with no problems and used one for our cats for 5 or 6 winters with no problems.

 

[tenderkat]

I tried to find my answer within the post, but I'm a bit confused. It's probably an obvious answer, but I just want to make sure I understand. When/If, pray not, a cord DOES get overheated, where exactly along the cord does the hazard occur, and how does it manisfest itself? Say, for instance, I have a cord plugged into the exterior outlet on the side of my house, run +/- 50 feet along the wet snowy ground, up into the run and connected to the dog bowl/appliance. When faulty/inadequate, does the cord itself begin to heat up, or is it the connections at the plug ends? Will the outlet against the house start on fire? I guess I'm just wondering what the actual logistics of the potential fire begin and where?

 

[RocketDad]

Quote:
I'm not an expert, but just an over educated enthusiast with a fruit salad of actual experience. I think I can explain this for you.

Resistance in an electrical circuit causes heat. Light bulb filaments are resistors, as are the coils of nichrome wire in toasters, hair dryers and cheap space heaters. The wire in the extension cord is a pretty good conductor, within limits, but it does have some resistance. The fatter the copper wire, the more amperage it can carry without noticable heating. Overload even a great conductor like gold, and it will heat up. The triggers in nuclear bombs use high voltage and very thin gold wires that instantly vaporize, setting off the chemical explosives that start the bomb.

In an extension cord, the highest points of resistance are the ends. The solid copper plugs and sockets get oxidised, creating resistance for the flow of electricity. The ends will get hot. That's how house fires begin - outlets overheat from overloading and/or high resistance connections. Hopefully, breakers pop first, but there was a problem years ago with aluminum house wiring causing fires because the connections with non-aluminum components heated/cooled at different rates and the screws in outlets worked loose. It was especially a problem in kitchen and bath outlets because of humidity - copper and aluminum will corrode when in contact. Building codes were changed, electricians were trained on proper installation of aluminum wire and outlets were redesigned to fix the problem, but if your house was built in the 1970's I'd suggest having an electrician inspect the outlet in question.

I've overheated extension cords, and still use them. They end up twisted like a phone cord, as the copper expands and then shrinks again. The twisty part will be at one end or another, from whichever connection had the highest resistance. If the end at the wall is the highest resistance, the outlet will also get hot.

I recommend owning a point-and-click infrared thermometer. Very useful tool, for things just like this.

 

[CrossBojangles]

Thanks for the detailed response. I am a first-time chicken owner (actually only a week), and I just got a heated water bowl with a similar warning. Your tips are Exactly what I have been looking for. I am definitely going to run a single outdoor extension cord. The cord that comes out of the bowl is protected by a metal wire that spirals the length of it. Not sure if I should throw a layer of duct tape over it as well for added protection?

The bow I got is the 1 quart one, and you can see the cord/cord protector/bowl here- http://www.farminnovators.com/pet.html

 

[WayneThopy]

I would go to a farm supply and get a heat lamp and put that in my coop. I would get a three gallon self waterer and 7-pound self feeder for their feed. They'll be good for two or three days on that. Just run a heavy duty outdoor cord with the outlet end enclosed in the coop and the prongs in another building. Put the heat lamp up as high as you can in your coop and be sure it is insulated. We ran these type of cords in the snow to thaw out cattle waterers and never had any problems! Our buildings were old.