Alternator output fuse #4 AWG
- Thread starter dugout
- Start date
What are the options for an "in-line" fuse with #4 wire within 7" of the alternator? I'm stumped
Fuse goes at battery bank end not alt end of wire.
I must be missing something. What protects the wire run between the ALT "B" terminal and a ground short in the path to the battery fuse?
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Yes, as pictured battery terminal fuse POS post. Alternator is charging the wire with flow from the ALT to the Battery. Wire shorts to the engine, quite possible, between the Alt and Battery and creates a dead short. I must not be descriptive enough; here is another diagram. Please excuse the kinder-garden art.
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dugout, I understand your question, which is: if the wire between the alternator and the battery shorts to the engine, what protects the length of wire between the spinning alternator and the break at the engine. Right?
Coupla things: the alternator will immediately cease output because the diodes will fry because you've interrupted the alternator output (AO); the fuse might blow first, also interrupting AO; in no case should one ever install an AO that goes anywhere near the engine that could cause this to occur in the first place. While alternators are obviously mounted right on engines, good electrical practice indicates that the AO should be routed away from the engine and supported properly to avoid your very reasonable concern.
Does that help?
Coupla things: the alternator will immediately cease output because the diodes will fry because you've interrupted the alternator output (AO); the fuse might blow first, also interrupting AO; in no case should one ever install an AO that goes anywhere near the engine that could cause this to occur in the first place. While alternators are obviously mounted right on engines, good electrical practice indicates that the AO should be routed away from the engine and supported properly to avoid your very reasonable concern.
Does that help?
Stu, thanks for the explanation. Yes, it makes sense. I can be a little slow.
I'm keeping the boat on the hill this year and rewiring it. I have sailed it without an electrical system or Aux since I got it so this is the chance to do it right. Here are some pictures of what I have and why I have treated it like a daysailer. It escapes words, to be honest. I do get a chuckle when I hear some talk about bad wiring.
It's a true testament that Cuban Cigars, Malt Scotch, and Maritime Museum Auctions DON"T MIX!!! In addition to everything else, She is haunted but that is another story for another time.
I'm keeping the boat on the hill this year and rewiring it. I have sailed it without an electrical system or Aux since I got it so this is the chance to do it right. Here are some pictures of what I have and why I have treated it like a daysailer. It escapes words, to be honest. I do get a chuckle when I hear some talk about bad wiring.
It's a true testament that Cuban Cigars, Malt Scotch, and Maritime Museum Auctions DON"T MIX!!! In addition to everything else, She is haunted but that is another story for another time.
Attachments
Alternators are "self limiting" and can not exceed the ampacity of properly sized wire...
Yes, and what you are protecting from with fuse close to the battery is 100s of amps coming FROM the battery in case of a dead short. The closer to the battery, the less cable exposed to the huge currents such a short can incurr. I'm learning slowly.