quick question about fuses

[SSS 18734 5,000+ posts]

I'm running 4 guage wire to a distrobution block, where it splits into a 4 guage and 8 guage wire... question is, do I need to fuse the 8 guage wire, or would it be safe running it without a fuse. I have it hooked up to a 200 wRMS amp. the other 4 guage goes into a 800wRMS amp.

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[RandyJ 10+ year member]

Yes you need to fuse it. A general rule of thumb is to make sure and fuse anytime you go from a larger wire to a smaller wire. Reason being the smaller wire cannot support the same ammount of currentas the larger wire can.

 

[ToyTundra 10+ year member]

you could squeak by without fusing the 4 guage out of the d-block, but that's not my style

 

[SSS 18734 5,000+ posts]

well i havnt had a problem with the 8 guage wire yet, been running it that way for about 2 months. Better safe than sorry though. Would it be a better idea to send a 4 guage wire to the 200wRMS amp instead, and just cut some of the strands off the end so that it would fit into the 8 guage terminal?

 

[stones 10+ year member]

The amp you have hooked to the 8/0 gauge wire has its own fuses on the side so I wouldn't worry about it, just have that all important fuse at the battery and you will be worry free.

 

[Chevyaudio 5,000+ posts]

I always fuse a wire when i drop the guage size.

 

[creater 10+ year member]

"you can never use to much fuses"

well maybe

 

[jujumantb 10+ year member]

Like said, it is the safest to fuse it again, but really the only way it would be a problem is if for some reason, your amp malfunctions and draws too much current for the 8 guage, but still not enough to blow the fuse on the 4 guage, and then that power would need to be sustained long enough to melt the wire... not likely, but hey, rule of thumbs are usually good to follow //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[johnecon2001 5,000+ posts]

The amp you have hooked to the 8/0 gauge wire has its own fuses on the side so I wouldn't worry about it, just have that all important fuse at the battery and you will be worry free.

You gotta fuse whenever you drop in gauge size too. The fuses on the amp protect the amp, not the wire... which is what can start a fire if it over draws and shorts out.

 

[stones 10+ year member]

I understand what you are saying what you are saying john, but logically the amp should stop drawing current as soon as the internal fuses blow and the length of the 8gauge coming from the distro block will be short enough that the main system fuse by the battery would blow before the wire generated enough heat to burn (a 4foot length can handle 125 amps continuous without overheating the insulation)).

If the the 8gauge coming off the distro was over 5 feet then I would certainly reccomend a fuse, but otherwise i don't personnally worry about it.

 

[IRACEMYCOPCAR 10+ year member]

Fuse every power wire and everytime you split it!! always fuse closest to the power SOURCE on every wire.

There is one factor that everyone is fogetting about, radiated heat.

i knew a guy that had a 4ga going from front to a cap and 8ga going to mids amp and 8ga going to bass amp, his 8ga wire must have been too close to the amp and because he didnt have a fan in a closed trunk the wire melted and grounded out, it burned up the amp,cap,box and cought the trunk on fire and still didnt blow the fuse under the hood because it didnt draw enough current. if he had fused it after the cap it would have blown and stopped it from catching on fire.

fuses are our friends, if one blows there is a reason and you need to figure it out.