I'm wanting to install a fuse before the ammeter so as not to set anything ablaze under the dash. Will a 30Amp fuse be sufficient? I've installed a new wiring harness and want to protect my investment, as many of you know their not cheap. Thanks for the info.
You can put a 50 amp fuse if all you need is short circuit protection.That will prevent a momentary surge from blowing the fuse.If you want to limit current to 30 amps,then fuse it for that.What ever you do,fuse it at the source,not at the amp meter.
I actually fired a 30 amp ammeter with a 65 amp alternator. I don't think that the alt was the culprit, I think that I had too much amp draw in my system and it was more then the meter could handle. There are way too many variables here to make a decision based on what we have been told.
Your fuse should be for the wire size that it is protecting. i.e. #14 wire 15 amp, #12 wire 20 amp, # 10 wire 30 amp, these are suggested sizes for general purpose wiring in you car. KK
That list is for building wire over current protection.Automotive wire is generally fused higher because of the short lengths and it doesn't have to comply to strict codes intended to last 100 years at maximum current . Vehicles will use a number 10 wire off an alternator that might generate 60 amps.Or several # 12 wires coming off a 60 amp common fusible link
I would fuse it to the max charging current if generator is under 30 amps. At or above 30 amps use the wire size leading to ammeter for fuse size. A resettable circuit breaker or fuse link is more forgiving than a normal fuse. Fuses blow and need replacing.
The voltage regulator used on a generator has an amp cutout. Cause generators are stupid and will fry themselves. The amp relay in the regulator takes care of limiting the output to protect the generator. IF you need the need for a fuse, put it on the "arm" terminal of the regulator. Frank
Ditto, fusible link ,...Most aftermarket harnesses provide them. They are a car's "life saver" 4TTRUK
Yes Squirrel it is 10guage wire also I should have mentioned I'm running a 6v system and generally stock rewire and generator. Also who sell 6v fusible links?
You really are trying to protect your system from somekind of dead short to ground I assume, 50 amp fuse will allow a 10 gauge wire to become very hot, I would go with 30 amps.
Fusible link or self resetting breaker would be my recommendation, I wouldn't put a regular fuse in there.
I used a 50a circuit breaker in my Dodge when I went to a 60 amp alternator and 12v. Also changed to #8 wire. I pulled the amp guage out and looked at the size of the shunt across the terminals. It was more than capable of handling 50 amps. Remember MOST amp guages are inductive, so its the size of the shunt that determines the "capacity" it is able to handle. No problems in 2 years and I have pegged the guage more than a few times.
No,a dead short or "bolted Short" will trip the fuse instantly,even a 50 amp fuse on a #14 wire. You might use a 50 amp fuse on a 10 wire strictly for short circuit protection.This prevents nuisance tripping from momentary surges.Overload protection is sized to the wire and the device you want to protect.Two different kinds of wiring protection...... Although I said car wiring does not adhere to building wire codes,it's a general guide worth considering even though vehicle manufactures don't.But keep in mind a shorter length of 14 wire on a vehicle can carry 20 amps no problem. I like fuses on vehicles except for the head lights.A fuse always blows,cheap car type breakers don't always trip fast enough. And always buy bran name fuses made in USA.
I found that Bussman carries a 30Amp auto reset circuit breaker that is made in the good ol' US of A! Would that be a good alternative to a fusible link so as not to be stranded roadside?
Maybe. usually those type breakers are used for accessory circuits, not the main power feed. There must be some reason why.
In case of a short circuit the fuse disconnects instantly to save the wire harness.Car breakers with the auto reset will go on and off and that's not what you want in a main feed.A non auto reset would be ok. I don't care for fusible links because they are fussy to replace on the roadside. If you don't mind the site of a modern fuse holder, Maxi fuses can be had from 20-80 amps along with fuse holders for 5 bucks..They are larger two blade fuses used on modern Jeeps.......easy to replace a fuse....
I can't remember ever having to replace a fusible link on the side of the road. Like I said earlier, craftsmanship goes a long way towards preventing electrical problems.
Jim...I think your reasoning of WHY is probably spot-on for the use of breakers with ACCESSORY circuits only. Accessory circuits usually fall under something that you could turn-off and reasonably expect to continue to safe haven without, if necessary, like a radio or heater motor, yet the breaker would initially protect from the BIG, ULTIMATE meltdown. That would be ONE reason for designing circuitry so carefully in the first place. DD
I did on Chevy vans,the link is buried down by the starter.Left a bad memory on my little brain. Other than that,i don't think I replaced more than 10 blown fuses in nearly 50 years. I'm am electrician by trade,not a mechanic. I'm used to fuses and or breakers lined up with easy access and at a glance you can see if it's blown or tripped.Car designers used to hide fuses like an afterthought.Late vehicle are much better with a fuse for every light and device and often with easy access
30Amp circuit breakers are used in many of the older light switches and are there to get you safely to an area where you can sort out the problem.
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