What fuse is appropriate for a B&G AC32N Autopilot Computer

[PelicanCarl]

What fuse is appropriate for a B&G AC32N Autopilot Computer? the installation manual doesn't give an answer.

[cram]

Which fuse? At the distribution panel to protect the wire or near the device to protect the device?

[PelicanCarl]

the AC42N receives power from a power distribution panel where each device has a switch and a fuse. I am trying to right size that fuse.

[cram]

The fuse at the panel is sized based on the wire size, not devices connected to it. The main purpose of a fuse is protecting from wiring fires,not protecting a device from malfunction. It can be smaller, but not larger than specified.

http://assets.bluesea.com/files/reso...e_Amperage.jpg

[s/v Jedi]

Originally Posted by PelicanCarl

the AC42N receives power from a power distribution panel where each device has a switch and a fuse. I am trying to right size that fuse.

The fuse protects the wire between the distribution panel and the ac42. As the ac42 has a 50A peak output rating, you need to find a cable size that can handle 50A load at a maximum of 3% voltage drop over the length of cable, positive plus negative conductors. You can find tables to find the right cble diameter.

The ac42 has an internal fuse to protect itself. It’s user replaceable.

For the distribution fuse of breaker, considering the 30A sustained, 50A peak current, a 60A or 80A fuse would be enough as the ampacity of the selected cable diameter should handle more than that as it is dimensioned for voltage drop instead of ampacity.

[smac999]

what is the fuse size under it's cover? assuming it's still there and that is not what you are trying to put back in.

2nd is what pump is it running. most pumps are only 5-10a. unless you have a huge pump large breakers are not needed.

[s/v Jedi]

Originally Posted by smac999

what is the fuse size under it's cover? assuming it's still there and that is not what you are trying to put back in.

2nd is what pump is it running. most pumps are only 5-10a. unless you have a huge pump large breakers are not needed.

I’m not aboard so I can’t look but it’s a blade fuse so I guess 30a or 40a. I believe 30a is the official maximum for those fuses but I do have some 40a ones.

I think a 30A fuse can deal with a short 50A peak without blowing but I’m really not sure, need to look up the specs and diagram and this can differ with brand.

[smac999]

Originally Posted by s/v Jedi

I’m not aboard so I can’t look but it’s a blade fuse so I guess 30a or 40a.

well I was trying to ask the poster. it sounds like they are trying to fuse it at the main panel. they should just open the cover and see what's inside. then fuse the same at the panel. asuuming the wire can take it.