I need two fuses for my power distribution block, how do i figure out how many AMPS these should be. My in line fuse at the battery is 80AMP.

thanks for your help.
J

 

what are the fuse ratings on your amp(s)?

if your front fuse is 80a, you can't exceed 80a combined in the distroblock. (eg. 20a + 60a fuses)

 

Also, your front fuse should be the total of all amps fuses, or the max for your wire, which ever is lower.

 

your fusing the wire not the amp! the wires rating applies here.
heres a link to help you answer your own question:
http://xxx.bcae1.com/wire.htm
look for the "system power design assistant" pic and input your info

gl

 

WIRE OR AMP WHICH EVER IS LOWER. I agree your ultimately protecting the wire, this is why you go with the lower of the two. And your link doesn't work...

 

fixed

http://www.bcae1.com/wire.htm

 

Cool, another site full of good info. THANKS!!

 

this is what i have:

4g from battery to distribution block.
8g from distribution block to two amps.

amp #1: 4 channel with two fuses of 15 amp each.
amp #2: mono with two fuses of 20 amp each.

have 80 amp fuse at battery and two fuses in block of 50 amp each.

is this ok or can it be better?

thanks

 

If you have no supply issues (dimming headlights etc.), that's fine.

HTH

 

you fuse to the system requirements not to the wire

the wire dictates a maximum fuse size of 125 amps, but since his system can realistically only draw 70 amps an 80 amp fuse is appropriate. Since the SYSTEM can not draw over 80A of power it stands to reason that if it draws 81 amps it has a fault and the fuse will protect the system (keeping a small fire a small fire).

at the distribution point you have a 30A and a 40A load and I would recommend fusing to the load. this would meet the overall system and individual loop power demands. the 50 amp fuses are a little over sized and I don't have issue with it though 30a and 40a would be better.