I'm looking at making a quick disconnect feature for my amp and I was wondering if having a 2nd fuse on the power wire was any kind of issue? I've got a 50A fuse about 6" off the battery, but it would be convenient just to be able to disconnect the power from the trunk instead of only from under the hood. Does the fuse rating matter? I was planning on just using another 50A fuse.

 

i don't think a second fuse at the amp matters at all, unless you are running a distribution block there. 50 amps may not be enough. I always ran 100+ amp fuse at the battery. i'm sure theres a calculation chart on the web somewhere of fuse amperage vs total system wattage.

 

Having a second fuse is okay.

Fuses are protective devices, and should be sized based on the wire size (and that by the power requirements of whatever is at the other end of the wire). The idea is that, in the event of an overload, the wire won't overheat and start a fire. For a 50A fuse, you should have something like 6 gauge or larger wire IIRC.

You could also use some sort of a suitable connector rather than a fuse if all you need is a disconnect.

 

Thanks, I've got 8 gauge wire. I saw a disconnect on Parts Express, but I was thinking it might be better to have no chance of the power wire coming in contact with anything else.

 

Is that 8 gauges American or International wire size? They are different, and generally most wires are labelled using the international size.

Anyway, back to the fuse question. If you have a 50A fuse close to the battery and if you plan to add an equal or lower amp closer to the device in your trunk, then it shouldn't matter, as long as you understand that the lower amp fuse will be the one to be blown first if things happen.

Here is a good chart on wire/length/fuse: Cable gauge chart

 

If you want a quick disconnect, Anderson Powerpoles are what you want to use they will not have an exposed contacts and if the open end really bothers you, you can order a cover. Order 2 red and 2 black plastic housing (around $2.60 total) and 4 contacts to match the size wire you are using and the power requirement (around $4.00).

Individual Housings, Contacts & Parts: Powerpole and SB Series housings, different gauge contacts and offered individually or bagged in small quantities at affordable pricing.

Here they are on ebay:

anderson power poles | eBay

 

Thanks for the links. I never would have thought of those. In the mean time, I ordered a second fuse for the power. I didn't realize before that it's not all the difficult to pull the REM, negative wire, and high level in plug. The amp is mounted to the sub, so that's one less wire pair to remove.