Do i have the right size of fuse in my power wire?

[ckunke002 10+ year member]

I know there are other threads on this topic, but I'm reading mixed reports so I want to get this clear.

Last week my fuse next to my battery blew, and I didn't know anything about fuses so I just took it into my local car audio shop and let them pick me out the proper fuse. I did a little bit of research after I got home and I'm not sure they gave me what I need. I'm running 4 gauge power wire, and they upgraded my 60 amp fuse that popped with a 200 amp fuse. To my understanding, my 800ish watt system only draws 50/60 amps of current and I can't imagine a 200 amp rated fuse protecting anything when hell breaks loose in my wiring system.

How many amps is 4 gauge power wire designed to carry and how does one determine the fuse rating they need? I've read in a few threads that fuse amp rating must be higher than amp's amp consumption (efficiency) but lower than the number of amps that the specific size of wire can safely carry. Is this correct?

Thanks anyone and everyone

Click to read more...

 

[brynm 10+ year member]

Copy paste from bcae1.com

Suggested Fuse SizesWire Gauge Recommended

Maximum Fuse Size

00 awg 400 amps

0 awg 325 amps

1 awg 250 amps

2 awg 200 amps

4 awg 125 amps

6 awg 80 amps

8 awg 50 amps

10 awg 30 amps

12 awg 20 amps

14 awg 15 amps

16 awg 7.5 amps

These are the recommended maximum fuse ratings for the corresponding wire size. Using a smaller fuse than what's recommended here will be perfectly safe.

200A is way too high for 4g wire.

 

[rebelfromva 10+ year member]

Up to around 1000 on 4g

 

[brynm 10+ year member]

Also, the fuse by the battery is there to protect the wire. The equipment will generally have it's own fuse protection.

 

[rebelfromva 10+ year member]

I use 300 on my 0 and aq

 

[brynm 10+ year member]

Up to around 1000 on 4g

1000A on 4g?

Re-read the OP, he's asking what fuse size to use. Not how much power he can use.

 

[ckunke002 10+ year member]

Do you think I could go into the shop and tell them that they gave me the wrong size and replace it with a 100 amp fuse?

 

[brynm 10+ year member]

I use 300 on my 0 and aq

Good for you?

I'm using 150A on my amp, only running my 1250w kicker right now that requires external fusing. I put the 150A at the battery to save myself another fuse and holder.

(yay me)

 

[brynm 10+ year member]

Do you think I could go into the shop and tell them that they gave me the wrong size and replace it with a 100 amp fuse?

Depends on the shop. I would certainly take it back and ask about it as well as asking why they gave you a 200a in the first place. Depending on length of run that could get your wire pretty **** hot if you had a partial short.

 

[rebelfromva 10+ year member]

Didnt see the amps part sir. Stand corrected

 

[audiobaun 5,000+ posts]

Ive ran 4ga in several vehicles, and I recommend the largest of a 150,more than 100 ANL of course..200 will start melting the coating on the wiring, and possibly the plastic under the dist block if you have one.Thats too much.120-150max

 

[ckunke002 10+ year member]

Ive ran 4ga in several vehicles, and I recommend the largest of a 150,more than 100 ANL of course..200 will start melting the coating on the wiring, and possibly the plastic under the dist block if you have one.Thats too much.120-150max

So the fuse is for keeping the amperage running through the wire down AND protecting the battery?

 

[SuperSaeYoung]

So the fuse is for keeping the amperage running through the wire down AND protecting the battery?

The fuse is there so when the amperage gets to high it burns the fuse instead of letting the wire get hot and melt.

Amp is the current, and watt is the power.

If you know you're only going to be using 50-60 amp and your wire is rated for 125 amp, it's safe to go with 80-100 amp fuse.

 

[ckunke002 10+ year member]

The fuse is there so when the amperage gets to high it burns the fuse instead of letting the wire get hot and melt.
Amp is the current, and watt is the power.

So unless I'm getting near the point of fuse breaking then it's all the same, right? For example, my wires aren't in more danger with a 200A fuse than a 100A fuse if I'm only running 40 or 50 amps through it? Or is that incorrect?

 

[SuperSaeYoung]

So unless I'm getting near the point of fuse breaking then it's all the same, right? For example, my wires aren't in more danger with a 200A fuse than a 100A fuse if I'm only running 40 or 50 amps through it? Or is that incorrect?

I'm not suggesting it nor anyone here would recommend it, did you figure out why the fuse blew? It's always better to be safe than sorry.

Having the 200 amp would be fine if you're planning on upgrading the wires in the future.