Melted ground wire on the CB (1 Viewer)

[gon2srf]

My Cobra WX 75XT CB has not been working well as of late so I took some time yesterday to check the antennae and wiring. What I found was quite disturbing. The ground wire from the power supply was burned to bare wire for about a foot towards a West Marine fuse box which provides a ground and fused power. The Cobra WX 75XT comes with a 5 amp inline fuse on the hot wire which is connected to the West Marine Fuse box where there is another 5 amp fuse.
The CB was still receiving power after the meltdown with a now bare ground wire completeing the circuit. All my connections are soldered and crimped with the wires all protected with flexible conduit.
As I understand it ground wires melt due to heat caused from resistance. Could this resistance have come within the power supply or is my wiring/ground to blame?
All of my aux. lights, CB, HAM, aux power outlets all run through the same West Marine fused box. The fuse box is grounded direct to the battery with 4/0. Everything has functioned faithfully for 3 years until now.
The CB has been removed. I am going to open the power supply and check resistance. Does anyone care to have a shot at diagnosing the problem or have any advice?

 

[Brentbba]

Almost sounds like you've got some sort of arc of power to that ground wire. I never ground things to the fuse box. I always ground separate to a good ground on the vehicle. Exception to that is the ham radio that wanted ground to the battery.

Sounds like you are luck not to have had an electrical fire sir!

 

[gon2srf]

Almost sounds like you've got some sort of arc of power to that ground wire. I never ground things to the fuse box. I always ground separate to a good ground on the vehicle. Exception to that is the ham radio that wanted ground to the battery.

Sounds like you are luck not to have had an electrical fire sir!

Only light power use items run through the fuse box which in turn is wired with 4/0 directly to the battery. There are no runs of wire longer than 4 feet and they are all oversize. This set up should and has allowed for little resistance.

I went out to the car at lunch and found the culprit. I replaced my Optima Yellowtop last month and the ground cable bolt had backed off was left barely attached.

My bad!

 

[SOCALFJ]

Interesting, i'd call the Solder Joint in Orange or swing by there with it and let them take a gander. That's scary.

 

[Brentbba]

I went out to the car at lunch and found the culprit. I replaced my Optima Yellowtop last month and the ground cable bolt had backed off was left barely attached.

My bad!

Glad you found it! Scary thinking you might be driving a fire trap!

 

[SOCALFJ]

Wow, i totally missed that. Glad you found the problem.

 

[gon2srf]

Thanks for checking in guys. I have been pretty meticulous with my truck but I have to admit I installed the Yellow Top in my parking garage at work and the lighting wasn't great. I should have waited and done it at home. That's what i get for not checking my work later on.

 

[Brentbba]

Well, my CB died at the trail head of Mojave. Was working just fine in the AVI parking lot. I left the inline fuse in the power harness and couldn't remember where that was. I checked the second fuse on the block in my engine bay and it looked fine. Ran the weekend w/o a CB. Lonely. Most of the group was CB only and only a few of us on ham bands.

Got home, checked the inline fuse (behind the footrest - doh!), and rechecked the fuse in the engine bay. Both still looked ok. Took the wire off where it was on my block and tried a different connector and it worked just fine. Relooked at the fuse and it still looked ok - go figure.

 

[gon2srf]

Well, my CB died at the trail head of Mojave. Was working just fine in the AVI parking lot. I left the inline fuse in the power harness and couldn't remember where that was. I checked the second fuse on the block in my engine bay and it looked fine. Ran the weekend w/o a CB. Lonely. Most of the group was CB only and only a few of us on ham bands.

Got home, checked the inline fuse (behind the footrest - doh!), and rechecked the fuse in the engine bay. Both still looked ok. Took the wire off where it was on my block and tried a different connector and it worked just fine. Relooked at the fuse and it still looked ok - go figure.

Bummer about Mojave, the radio I mean. I carry a couple of FRS radios just for that reason and for those folks who come along with no radio, sort of like you did. LOL

So you got it operating again that's good. It's funny what you said about forgetting where everything is. I hadn't gone through my wiring in 3 years, it was a good review.

So from now on I will fuse both negative and positive wires on all of my sensitive equipment, i.e. ; radio, stereo, GPS just to be safe and as you said direct ground on the radios to avoid any interference.