Clouddancer
Well Known Member
I'm not an electrical expert and might get myself massacred by the following question
Has anyone done a direct electrical ground cable/strap directly from the firewall grounding point to the starter/alternator? This, instead of running a ground strap from the firewall to the engine case. This will probably not add much more than 1.5 ft of fat wire and the respective weight. But won't it be a more predictable conductor than the engine case?
Depending where you attach the ground strap/cable you will have several aluminium to aluminum interfaces, some of them with sealants between them. So in worst case, only the bolts will conduct the current. Most of the bolts are steel with a conductibility that is approximately 7 times less than copper, i.e. you will need 7 times the cable's cross section in bolt's cross sections.
Example: 2AWG cable -> 0.0521 inch2 cross section, almost the same cross section as an AN4 bolt (0.049 inch"). So it would need at least 7 AN4 bolts to have the same conductivity as an 2 AWG copper cable.
So, in that point of view, the engine case is not a very predictible conductor. Any experience or opinions?
Has anyone done a direct electrical ground cable/strap directly from the firewall grounding point to the starter/alternator? This, instead of running a ground strap from the firewall to the engine case. This will probably not add much more than 1.5 ft of fat wire and the respective weight. But won't it be a more predictable conductor than the engine case?
Depending where you attach the ground strap/cable you will have several aluminium to aluminum interfaces, some of them with sealants between them. So in worst case, only the bolts will conduct the current. Most of the bolts are steel with a conductibility that is approximately 7 times less than copper, i.e. you will need 7 times the cable's cross section in bolt's cross sections.
Example: 2AWG cable -> 0.0521 inch2 cross section, almost the same cross section as an AN4 bolt (0.049 inch"). So it would need at least 7 AN4 bolts to have the same conductivity as an 2 AWG copper cable.
So, in that point of view, the engine case is not a very predictible conductor. Any experience or opinions?
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