I am chasing a strange problem w/ some 12 v electrical wiring (properly sized to carry a 5 v signal voltage. I've noticed that when a properly sized (OEM) to carry a 5 v signal voltage gets hot, often the signal voltage drops randomly to 2.3v or so. Assuming the electric connections are sound, clean and good , do 12v copper wires deteriorate due to old age, or heat exposure? continuity checks when 'cold' show no problem.
Does 12v wiring deteriorate with heat or age ?
- Thread starter MitchM
- Start date
It is not the voltage that causes heat, it is the amperage.
Wire that has been exposed to salt water can have salt migrate up the wire and cause corrosion beneath the insulation.
As wire heats up, resistance goes up and voltage drops. Is this a consistent problem or truly random? What devices are on the wire? Is the wire fused?
Have you considered that the device may be the culprit and not the wire? A failing device could cause more amperage to flow than the wire can handle causing it to over heat.
Wire that has been exposed to salt water can have salt migrate up the wire and cause corrosion beneath the insulation.
As wire heats up, resistance goes up and voltage drops. Is this a consistent problem or truly random? What devices are on the wire? Is the wire fused?
Have you considered that the device may be the culprit and not the wire? A failing device could cause more amperage to flow than the wire can handle causing it to over heat.
Assuming the OEM wire is properly size may be a bold assumption, especially if any of the devices on the wire have been changed.
I am rather confused by your statements. You talk of 12v wiring, so I think that is low voltage wires, not 120V or high voltage wiring. but then you speak of 5V signals, so that suggests wires that do not have any significant current flowing. Then you speak of these signal wires getting hot and causing a voltage drop.
If you are getting a voltage drop in a wire, you absolutely cannot 'assume' that the connections or terminations are good. And performing a continuity check to test the integrity of a wire will tell you very little unless the wire has a very serious problem. A continuity check will not show any significant voltage drop because the test current is very low.
Perhaps you can explain more about your issue.
If you are getting a voltage drop in a wire, you absolutely cannot 'assume' that the connections or terminations are good. And performing a continuity check to test the integrity of a wire will tell you very little unless the wire has a very serious problem. A continuity check will not show any significant voltage drop because the test current is very low.
Perhaps you can explain more about your issue.
You are speaking of "signal wire", if signal is traveling through it and you are using a DC voltmeter, then you are measuring the average ac signal. And, cold or hot, are you referring to ambient temperature causing the change or that when the wire is energized with the signal?
If you have a signal wire which shows any evidence of getting hot, you definitely have a problem. Perhaps a partial short in the line ?
The drop in voltage from 5V to 3.2V further indicates an unwanted grounding.
When DC voltage drops to 1/2 of what it's supposed to be on a wire it's usually because the load has doubled and not because the temperature of the wire has increased. Wire is usually identified by its size because it's rarely ever sent out of the factory with the voltage on it.
@Ralph Johnstone - I don't recall granting you permission to use my trophy husband image in your posting. But thanks for the recognition! 
Last edited:
OMG, you're right, it's all there :
- The clean shaven look (right to the bottom of the skin folds)
- The blemish free skin (with the exception of a few warts)
- The steely blue eyes (looks like one blew east and one blew west). Welllll, one out of two ain't bad.
- The hat worn at a jaunty angle.