how hot?

[swynx]

Just curious how hot wires burn...

Was driving on the high way when I kept hearing sparks. Looked saw nothing. Heard it a few more times with some flashes. I was like WTF. Then I look down and see a wire bright as fire. Reached down ripped it out. Thought it was because I used to small guage of wire on the lights. (Installed aftermarket driving lights on the Saturn for dear). Or a pinched wire.

I clipped the wire today not sure what it went to. But I'm assumingbit was the power wire for the radio. I couldn't find it before. Any who it was bouncing off the only ground in the area.

The wire seated right thru my skin. Didn't bleed yet.

Could have been way worse.

 

[Mark_88]

I know they can get pretty hot under load because I burned my finger on my electric choke wire...and promptly removed the choke...

Also had the 4 way flashers on my Zuki start to smoke one day...never had the column trim off so fast...but the signal switch fried for no apparent reason and ended up costing my $600 to replace it...

 

[lil_Blue_Ford]

How hot is largely a function of wire diameter and amperage. Safe to say that it can exceed the melting point of the wire (copper or aluminium). In theory a direct short (which would be a typical cause for a wire of the proper size to heat up to burn) should cause the fuse to pop (assuming it is a properly fused circuit). But it doesn't always happen. When a wire too small is used, the wire often burns through before the fuse pops since the wire becomes the fuse.

 

[RonD]

You can weld with 12volts and 45amps

Most vehicle fuses are 30amps or less.

I would suspect that wire was hooked to battery without fuse protection, starter solenoid post, 12v side in power distribution box or the inside fuse panel, so I would trace it back to the source or you may get a repeat performance with what is left of that wire.

Smaller wire size AND larger wire size can be the wrong choice.
If you use too small a wire for the amp draw of the device then wire will heat up and insulation could melt causing a direct short or fire.
Too large a wire, if not correctly fused, can weld itself to ground if shorted, battery could explode, nearby wiring could melt, fire,........nothing good is the point, lol.
So correct wire size should be used for length and amp draw, going to larger wire, just to be safe, may not be the best decision, unless fused close to the power source.

Fusable links are based on too small a wire, they use a short wire(metal strip), that will melt and break the connection if amp draw rises above their rated capacity.
Just like a fuse, but these are more tolerant of short spikes in amps.

 

[swynx]

You can weld with 12volts and 45amps

Most vehicle fuses are 30amps or less.

I would suspect that wire was hooked to battery without fuse protection, starter solenoid post, 12v side in power distribution box or the inside fuse panel, so I would trace it back to the source or you may get a repeat performance with what is left of that wire.

Smaller wire size AND larger wire size can be the wrong choice.
If you use too small a wire for the amp draw of the device then wire will heat up and insulation could melt causing a direct short or fire.
Too large a wire, if not correctly fused, can weld itself to ground if shorted, battery could explode, nearby wiring could melt, fire,........nothing good is the point, lol.
So correct wire size should be used for length and amp draw, going to larger wire, just to be safe, may not be the best decision, unless fused close to the power source.

Fusable links are based on too small a wire, they use a short wire(metal strip), that will melt and break the connection if amp draw rises above their rated capacity.
Just like a fuse, but these are more tolerant of short spikes in amps.

Yeah I was going to trace it. It actually comes out of the factory wiring harness. Its the same size as speaker wire. So Idk what in the hell you could have powered with it... led?

Not sure why the fuse for it didn't blow.

 

[Scrambler82]

That is why you run a fused sized to the small component on a circuit.
16 ga wire = 10 a fuse max.
12 ga wire = 20 a fuse max
10 ga wire = 30 amp fuse max.

Fuses larger than those about and and over loaded circuit or component will result in a hot condition. If a direct shorted wire with an oversized fuse can result in a fire.

Properly installed fuses are usually installed close to the power source so if it blows all the power is shut off close to the source.

How did you have things hooked up ?
What is the circuit load, the component sizes, wire gauge, fuse size, total load ?

Just over all interested.

Ltr

 

[simpler=better]

A big quick disconnect (that goes directly on the negative battery post) is great to have in case something starts to short

 

[swynx]

I didn't wire any thing in. There is a hot wire that goes into a connector. Then 2 wires come out. One has a fuse and the other doesn't. The one that doesn't have a fuse is the one that touched bare metal and got red hot. Somebody wired in a pigtail. And I have no idea what its for, any ideas?

I found 4 more bare wires that were from this that are hot. I cut the ends and put liquid electrical on the ends.

 

[adsm08]

FWIW I have seen more than one GM wire catch on fire for no apparent reason at all.

I have repaired numerous burnt wires in GM HVAC systems, and one time I tried to jump start an Equinox (customer claimed she left the lights on) with a booster pack, using the designated hook-up points, and when I turned the key the power distribution block and a large part of the engine bay wiring quickly turned into slag.

 

[swynx]

Whoever wired that in did a clean job they just left out that one wire.

 

[lil_Blue_Ford]

FWIW I have seen more than one GM wire catch on fire for no apparent reason at all.

I have repaired numerous burnt wires in GM HVAC systems, and one time I tried to jump start an Equinox (customer claimed she left the lights on) with a booster pack, using the designated hook-up points, and when I turned the key the power distribution block and a large part of the engine bay wiring quickly turned into slag.

Somehow I'm not surprised.

 

[RonD]

Like water flows in the easiest downhill path, Electricity always finds the easiest path to ground(it's downhill).

Over the years the vehicle ground straps are often left off after repairs and ground points are usually not touched so can get corroded without you knowing about it.

The Main ground cable from the battery should run to the engine block, then block or head should have ground straps to Frame and Firewall.
Then ground straps from frame to fender wells and rad support, while these are "bolted" together they often have rubber grommets and are pre-painted parts when assembled so there is no bare metal ground connection between them.

Grounds are not fuse protected, so if a good ground wire that is 16gauge which normally would only carry a 10amp load has to also carry an extra 30amps because the 30amp circuits ground is loose or corroded then that 16gauge wire heats up.
As far as the 12v fuses for those circuits are concerned there is no power(over amp) increase, at least not enough to blow the fuse.

Good Grounds at important.
Find all your ground straps and make sure they are making good contact, add you own if you can't find them, you can't "over ground" a vehicle, lol.
Check any ground points you can see, loosen bolt move wires around then re-tighten, or remove clean and re-tighten.

 

[swynx]

My buddy adds a ground to everything