Quote:
Originally Posted by davids2toys
So your MSD box wire is not protected if the car is running because you have it hook up to the protected side of the CB.
Why is the CB there then? What is protecting this when the car is running, the glass fuses?
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The car will not be running if: 1) the MSD box shorts out (which will blow the internal 15 amp fuse on the MSD circuit board) or 2) the feed wire to the MSD box shorts out (because the box itself will no longer be fed. If the MSD feed wire shorts out, or if the line that leads to the ammeter shorts out, the circuit breaker will blow because the battery will try and pump lots of amps through that line even if the alternator is still turning. The glass fuses protect shorts on the load side, for the most part. Remember, almost all of the wires in your car, even the skinny little wires, will handle 50 amps for a short while <pun>. and the CB will blow if the battery dumps more than that. One of the most common wiring fires is the result of a short in the line between the alternator and the battery (the one with the ammeter in between). If this line shorts out, the CB will blow, but the alternator will still pump out its maximum for a while, and that's where the fire comes from. Now, my alternator only puts out 60 amps, so the location of the fault will spark and smoke, and maybe some plastic nearby might catch, but the wire itself can carry 60 amps with no trouble. Some of the bigger alternators are a different story.