1970mcss Posted January 18, 2018 Share Posted January 18, 2018 I have a question about the negative battery cable, is the lead from the terminal a wire or a fusible link??? I didn't have the cable grounded to the alternator bracket and was cranking over the engine and the cable started to melt. The cable was new but the wire to the fender was not. I'm not sure what to replace it with.... Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted January 18, 2018 Share Posted January 18, 2018 There would never be a fuse or fusible link in the negative battery cable or any negative/return to ground wire. I didn't have the cable grounded to the alternator bracket and was cranking over the engine and the cable started to melt. The thicker/main lug on the negative battery cable carries the load of the starter. The small wire just grounds the body, which is somewhat isolated from the chassis and engine/starter. If only the small wire was connected, the 150+ amps of the starter load would predictably burn it pretty well. Replace with a new negative wire set. Quote Link to comment Share on other sites More sharing options...
1970mcss Posted January 18, 2018 Author Share Posted January 18, 2018 Thanks, that's what i get for trying to turn over the motor before I had the wires all correctly hooked back up. I was trying to set top dead center on the distibutor. Do you know what guage wire should be used from the small lead to the fender? Thanks again.. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted January 18, 2018 Share Posted January 18, 2018 I believe it's 10 gauge. Quote Link to comment Share on other sites More sharing options...
1970mcss Posted January 18, 2018 Author Share Posted January 18, 2018 Thanks Quote Link to comment Share on other sites More sharing options...
Rob Peters Posted January 18, 2018 Share Posted January 18, 2018 The negative battery cable should attach to the alternator upper bracket. The small wire coming from the negative terminal lead should attach to the fender (Mine is a 70 so I can not speak for the 71-72 on this small wire on the fender). The cause of the negative lead melting could be a couple things. The first thing that comes to mind would be a very high load (like the starter motor) having a direct short but if it the starter was shorted I don't think it would turn over. The second thing that comes to mind would be where it is connected to the car there is very high resistance from the connection being a poor connection. A poorly connected wire will create heat. Regarding the fuse-able link, that would be on the positive side, not the negative. If the small wire was not connected to the fender it would not cause this issue. When I got my car it did not even have this wire on the negative terminal. Without this wire connected to the fender it can cause flickering of the dash lights, interior lights, headlights etc. I hope some if this information helps. rob Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted January 18, 2018 Share Posted January 18, 2018 I believe it burned because he stated the main heavy wire & lug was not bolted to the alternator bracket. Quote Link to comment Share on other sites More sharing options...
1970mcss Posted January 18, 2018 Author Share Posted January 18, 2018 Rob, the loose connection we my dumba** for not hooking up the ground wire to the alternator bracket. I have re-installed the factory intake and putting the car back to factory and had the cable disconnected. I was trying to advance the distributor to set top dead center and never thought about the ground wire. I cranked the starter a bit and then noticed the wire to the fender melting. I have re-ordered a new negative cable and going to repair the small wire. Thanks for your input...Paul Quote Link to comment Share on other sites More sharing options...
Rob Peters Posted January 19, 2018 Share Posted January 19, 2018 I believe it burned because he stated the main heavy wire & lug was not bolted to the alternator bracket. My bad, I did notice he was saying he did not connect the heavy negative cable to the alternator and assumed he had connected it to another location. Yep, not connecting the end of the heavy cable but the small wire to the fender definitely would fry trying to carry that kind of a load. As long as you were ordering a new cable, why not order one with the wire attached. Here is a link to an original style negative cable with the snap type battery top mount connector with the small wire attached: https://www.luttyschevy.com/search.html#!year%3D1970%7C%7Cmake%3DCHEVROLET%7C%7Cmodel%3DCHEVELLE%7C%7Csq%3Dbattery%20cable They have them a Lutty's Chevy Parts or luttyschevy.com rob Quote Link to comment Share on other sites More sharing options...
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