Wiring to fuse block from battery - need in line fuse?

[NatedoggAZ]

Hey All,

I just installed a new master dual battery switch on my boat. Everything is wired up through the new fuse block - except for the trim pump - that is direct connected to battery.

Off the fuse block, I have a new radio, 300W amp, blower, and a USB/cigarette lighter socket.

I am only using 1 battery now - but wanted a master switch to expand to 2 later if need be...

OK - on to my question:
Do I need to install an in-line fuse from the battery to the fuse block?

I have one already with a 50A or 60A fuse in it - I just have not yet put it on if needed.
I am using 8 gauge wire from the battery to the block on a 20ft boat - so the wire length is maybe 18ft including slack.

Thanks!

ND

 

[dingbat]

Hey All,

I just installed a new master dual battery switch on my boat. Everything is wired up through the new fuse block - except for the trim pump - that is direct connected to battery.

Off the fuse block, I have a new radio, 300W amp, blower, and a USB/cigarette lighter socket.

I am only using 1 battery now - but wanted a master switch to expand to 2 later if need be...

OK - on to my question:
Do I need to install an in-line fuse from the battery to the fuse block?

I have one already with a 50A or 60A fuse in it - I just have not yet put it on if needed.
I am using 8 gauge wire from the battery to the block on a 20ft boat - so the wire length is maybe 18ft including slack.

Thanks!

ND

yes.....

Battery should be grounded to motor with much larger wire. 2 awg would be more appropriate

What size wire did you run from the fuse to the new box?

 

[NatedoggAZ]

a very large cable - maybe 2AWG is used from the motor direct connected to battery for both positive and negative.

To be more specific: I am using 8 gauge wire from the battery to the fuse block on a 20ft boat - so the wire length is maybe 18ft including slack.

 

[dingbat]

To be more specific: I am using 8 gauge wire from the battery to the fuse block on a 20ft boat - so the wire length is maybe 18ft including slack.

The length of wire doesn't come into play except when calculating voltage drop.

You fuse for the smallest wire in the circuit. Assuming you used 8 AWG ground wire as well, you would fuse to 50 amps max..

 

[NatedoggAZ]

Yes - I also used 8AWG from the battery to the new fuse block.
Thanks for the input - I will put a 50A in-line fuse onto the positive feed from the battery to the fuse block.

-ND