Electrical Overheating

Chris562

Active Member
I have had my North Country for two years now. It has the upgraded AC unit in it. I have noticed that if it is really hot outside (as it has been in Kentucky all summer) and I have to run the AC a lot, the electrical panel is getting MEGA hot. It has even tripped all the breakers for the camper. I also found where the outside electric plug has gotten so hot, the copper has turned colors and melted the plastic housing. I used an extension cord that day but is a factory produced cord specifically made for 30amps and purchased at a reputable RV dealer. I am beginning to get a little concerned about these issues. When the dealer installed the upgraded AC unit, should something else have been done to upgrade the wiring or breaker(s)? If so, what do I need to look for to make sure it was done? Any help is appreciated.
 

branson4020

Icantre Member
Disconnect from shore power, pull the face off the breaker panel and check all the connections for tightness, especially the main service connections.
 

lwmcguir

Well-known member
Sounds like voltage drop due to either the cord or the panel supplied voltage. You would need a 6-8 wire gauge extension cord to avoid voltage drop. Check your voltage under this conditions and see if you are anywhere near 120 Volts. i have discolored my plugs in the past trying to run the ac on a 12 gauge extension cord. Not good and hard on the AC.
 

Chris562

Active Member
I have been keeping a eye on this and the factory power plug is starting to get a fried look on the face where the prongs come out. The prongs aren't looking to good themselves. I noticed that the factory cord gets really hot to the touch when I have the AC running on high an extended amount of time. I had an Outback before my Heartland and the power cord never did this. I will try to do a reading with a volt/ohm meter the next time. I keep forgetting to take mine with me when I go out. I will let you know about the draw.
 

wdk450

Well-known member
Gang:
You know heat in an electrical circuit is a function of poor (relatively high ohmic) connections and high current loads (In Ohm's law parlance the wasted heat Power in Watts is equal to the current in amps SQUARED times the resistance (P= I x I x R). If your poor electrical connection goes from 0.5 ohms to 2 ohms on that 30 amp circuit then you went from 450 watts of heat to 1800 watts of heat. A toaster is about 1000 watts of heat.
We don't know how well the rubber molded plugs have the wires connected to the plug blades as tghis is sealed up. This could be a poor connection. The one thing we CAN do with the heating plugs/sockets is spray the metal surfaces with electrical contact cleaner/restorer. I like Cramolyn, available at Radio Shack.
For the circuit breaker box, I agree that every connection screw should be good and tight, and the wire ends disconnected and inspected for excess conductor metal removed when they were stripped.
Circuit breakers are switch contacts that can get hot when they start to fail. Industrial concerns have their breaker panels tested with infrared thermometer devices to identify failing breakers.
 

Chris562

Active Member
Gang:
You know heat in an electrical circuit is a function of poor (relatively high ohmic) connections and high current loads (In Ohm's law parlance the wasted heat Power in Watts is equal to the current in amps SQUARED times the resistance (P= I x I x R). If your poor electrical connection goes from 0.5 ohms to 2 ohms on that 30 amp circuit then you went from 450 watts of heat to 1800 watts of heat. A toaster is about 1000 watts of heat.
We don't know how well the rubber molded plugs have the wires connected to the plug blades as tghis is sealed up. This could be a poor connection. The one thing we CAN do with the heating plugs/sockets is spray the metal surfaces with electrical contact cleaner/restorer. I like Cramolyn, available at Radio Shack.
For the circuit breaker box, I agree that every connection screw should be good and tight, and the wire ends disconnected and inspected for excess conductor metal removed when they were stripped.
Circuit breakers are switch contacts that can get hot when they start to fail. Industrial concerns have their breaker panels tested with infrared thermometer devices to identify failing breakers.

WDK450,

That was the best answer I have ever received. I actually understand what you said. Do you think it would be a good idea to replace the end with a new one? That way I can secure the wiring inside the plug myself and routinely inspect it. Thanks again for your explanation.

Chris
 

TedS

Well-known member
Check the resistance of the extension chord end to end. The resistance should be nearly zero. If not near zero, the extension chord is causing voltage drop.
 

wdk450

Well-known member
Chris and Ted:
Yes, a plug end you wire on and know is a good connection is a good idea if the problem remains. A poor outlet can also cause heating that gets thermally transferred.
Checking the resistance of something that should be in the milliohm range is difficult, and requires a conductivity meter that reads in Siemens (the inverse of resistance ohms). You may be able to deduce something by testing the supply voltage at the outlet plug under load (You can do this by unplugging the 30/50 amp plug slightly enough to get voltemter probes on the blades, testing again at the next point on the trailer you can get access to (back side of supply jack or circuit breaker panel, noting the voltage drop, and measuring the amperage draw using a clamp on ammeter. If you have 3 volts of drop with a 30 amp load then your resistance is 3 volts divided by 30 amps or 0.1 Ohms (E/I=R), which is a power loss of 90 watts (IxIxR). I would think that distributed resistances of less than 0.5 Ohms should be O.K., but less is always better.
 
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