Question about fuse size
11-10-2002, 05:51 PM
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Question about fuse size
I'm installing 2 amps, a JL 500/1 and 300/4. The 2 fuse requirements add up to 90 amps. The fuses available only come in 80amp or 100 amp size, no 90amp size. Should I get the 80amp (main fuse holder) fuse to prevent overstressing the amps before the fuse blows? Also, do I need to run fuses in the distribution block, or is it not necessary. Thanks...
11-11-2002, 02:31 AM
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If I get you right, you are adding TWO extra amps, and the total fuse needed for BOTH amps equals 90amps?
To be safe, you can't go wrong by going with the 80amp size. However, depending upon how big of guage wire you are using, you might get away with a 100amp fuse. BUT BOTTOM LINE, you DON'T WANT A FIRE IN YOUR FIREWALL! So better safe, than sorry... I would start with 80amp fuses and buy some spare 100amp fuses. If you find that during REALLY loud cranking, you occasionally keep blowing the 80amp fuse to the point that it becomes a nuisance, then I would jump up to the 100amp rating.
BUT MORE IMPORTANTLY... YOU WANT TO FUSE EACH AMPLIFIER WITH IT'S PROPER RATING! So if for example, one amplifier wants a 60amp fuse and one amplifier wants a 30amp fuse, and that is how you are coming up with your 90amp total... Then you definitely want to add these individual fuses in line with each individual amplifier. An amplifier that needs a 30amp fuse IS NOT PROTECTED by having a 80amp or 100amp fuse as it's only protection! Internal wiring and components may not be able to handle drawing 80amps during a failure or a short circuit somewhere... IN THIS CASE, YOU COULD EXPERIENCE A FIRE INSIDE OF THE AMPLIFIER!!!
Think of it as your house... You probably have a 100 amp MAIN breaker to service the entire house... then you have a breaker (distribution) panel to distribute the individual loads. Each of these are fused at different ratings using circuit breakers. 30-50amps for heavy loads like the washer and dryer or AirConditioner, and 15-20amps for convenience outlets, etc.
In other words, every single appliance whether it be in your house or in your car... NEEDS to be fused at the proper rating. YOU DON'T WANT A FIRE IN YOUR TLS AND HAVE THE INSURANCE TURN DOWN YOUR CLAIM DUE TO FAULTY OR NEGLIGENT WIRING MODS!!!
Just be safe out there... 100amps is a LOT of power. THIS CAN BURN WIRES INTO FLAME EASILY, even if it is only 12 volts!
SO YES, YOU DO NEED to run additional fuses from your distribution block to your individual amplifiers. Unless they are already included in their individual wiring harnesses. Even then, it's best to have the fuses the closer to the battery as possible. This gives you the less chance of developing a short somewhere BEFORE the fuse. 16Gauge wire would just burn up rather than cause a 100amp fuse to blow... so a lot depends up on the wiring gauge involved. I'm sure a lot of other members can give you exact values for current that certain gauge wire can handle. I have them in a table at work, but not in my hands right now. Off the top of my head... 14Ga is good for 15amps, 12Ga is good for 20amps.... Other values, I would have to look up.
Hope this helps!
Good Luck!
SB
To be safe, you can't go wrong by going with the 80amp size. However, depending upon how big of guage wire you are using, you might get away with a 100amp fuse. BUT BOTTOM LINE, you DON'T WANT A FIRE IN YOUR FIREWALL! So better safe, than sorry... I would start with 80amp fuses and buy some spare 100amp fuses. If you find that during REALLY loud cranking, you occasionally keep blowing the 80amp fuse to the point that it becomes a nuisance, then I would jump up to the 100amp rating.
BUT MORE IMPORTANTLY... YOU WANT TO FUSE EACH AMPLIFIER WITH IT'S PROPER RATING! So if for example, one amplifier wants a 60amp fuse and one amplifier wants a 30amp fuse, and that is how you are coming up with your 90amp total... Then you definitely want to add these individual fuses in line with each individual amplifier. An amplifier that needs a 30amp fuse IS NOT PROTECTED by having a 80amp or 100amp fuse as it's only protection! Internal wiring and components may not be able to handle drawing 80amps during a failure or a short circuit somewhere... IN THIS CASE, YOU COULD EXPERIENCE A FIRE INSIDE OF THE AMPLIFIER!!!
Think of it as your house... You probably have a 100 amp MAIN breaker to service the entire house... then you have a breaker (distribution) panel to distribute the individual loads. Each of these are fused at different ratings using circuit breakers. 30-50amps for heavy loads like the washer and dryer or AirConditioner, and 15-20amps for convenience outlets, etc.
In other words, every single appliance whether it be in your house or in your car... NEEDS to be fused at the proper rating. YOU DON'T WANT A FIRE IN YOUR TLS AND HAVE THE INSURANCE TURN DOWN YOUR CLAIM DUE TO FAULTY OR NEGLIGENT WIRING MODS!!!
Just be safe out there... 100amps is a LOT of power. THIS CAN BURN WIRES INTO FLAME EASILY, even if it is only 12 volts!
SO YES, YOU DO NEED to run additional fuses from your distribution block to your individual amplifiers. Unless they are already included in their individual wiring harnesses. Even then, it's best to have the fuses the closer to the battery as possible. This gives you the less chance of developing a short somewhere BEFORE the fuse. 16Gauge wire would just burn up rather than cause a 100amp fuse to blow... so a lot depends up on the wiring gauge involved. I'm sure a lot of other members can give you exact values for current that certain gauge wire can handle. I have them in a table at work, but not in my hands right now. Off the top of my head... 14Ga is good for 15amps, 12Ga is good for 20amps.... Other values, I would have to look up.
Hope this helps!
Good Luck!
SB
11-11-2002, 09:54 PM
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Southbound, thanks for your in-depth explaination. You cleared up the questions I had about fusing my system.
I've read a lot of your posts (as well as Iggy) and you two have given me the confidence to setup my very 1st system with confidence.
Thanks...
I've read a lot of your posts (as well as Iggy) and you two have given me the confidence to setup my very 1st system with confidence.
Thanks...
11-15-2002, 12:48 PM
#5
Three Wheelin'
Rule of thumb for installing amps: Use a resettable circuit breaker and it should be mounted no more than 18" from the + battery post. then use 4 or 8 gauge wire from the breaker back to the amps and use a distribution block for connecting up the main power feed to each amp. As long as the power cable is run properly through a grommet passing into the firewall, and is not pinched with any screws, or trim panel clips, you can go with the 100AMP breaker up front, and then fuse each amp off the distribution block. The only reason for the circuit breaker up front is to act as a fail safe in case anything ever stabs into the power wire and shorts it out. Wire fires cannot be put out, they generally have to burn themselves out. A 100AMP whack will still cause alot of smoke but the breaker is up there to prevent it from getting out of hand. The fuses for each amp by contrast are there to protect each amp individually.
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