Bilge pump fuse question?

[BAD ORCA]

Installing a new bilge pump switch (Blue Seas 8263) auto-off-on switch. The wiring diagram shows two fuses on the mains DC positive wire. There is a 15A glass fuse built into the switch panel and an inline fuse not specified. The main positive feed wire comes from source to the glass fuse on the switch. From this glass fuse the wire connects to the center pin on the back of the actual switch to supply power.

Can i just bypass this glass fuse and connect my main positive wire to the center pin on the switch IF i fuse the main positive wire at a Blue Seas fuse block first?

 

[dlochner]

I assume this is the switch:

https://d2pyqm2yd3fw2i.cloudfront.net/files/resources/instructions/9838.pdf

The concern is wire size. If fuse at the main panel is sized for the smallest diameter wire in the circuit the panel fuse could be omitted. However, for the small cost of the fuse, I wouldn't eliminate it. The fuse will give an added layer of protection that is more easily accessible than a fuse at the main panel and would allow you to use a larger wire from the panel to the switch to reduce line loss before using a smaller wire from the switch to the pump.

The risk for the pump is something jamming the pump causing the pump to short out or overload. In that case the shorter the distance to the fuse, the better.

The only downside I see to using the fuse is having one more connection in the circuit, that seems to me to be a minor concern.

 

[DArcy]

I'm not sure why you would want to do that. I wired mine the way the manufacturer's wiring diagram indicates. The "FUSE POSITIVE FEED" on mine is the fuse at the battery and is MUCH higher current than would be appropriate to protect the bilge pump and its wiring.

You could use external circuit protection but why not use the one supplied with the switch? If the fuse were to blow, that would be the obvious place to check first, not trying to trace to some other location.

I see Dave beat me to it. It looks like we are saying essentially the same thing.

 

[BAD ORCA]

I'm not sure why you would want to do that. I wired mine the way the manufacturer's wiring diagram indicates. The "FUSE POSITIVE FEED" on mine is the fuse at the battery and is MUCH higher current than would be appropriate to protect the bilge pump and its wiring.

You could use external circuit protection but why not use the one supplied with the switch? If the fuse were to blow, that would be the obvious place to check first, not trying to trace to some other location.

I see Dave beat me to it. It looks like we are saying essentially the same thing.

Because i have a custom made plexi panel im mounting the switches to. It has a very limited footprint. I even had to remove the switches from the metal panel they were installed in to make them fit. If i can eliminate the glass fuse i can fit three pump switches on the panel. If i have to include the fuse then only two.

My batteries are fused. Maybe i read the instructions too fast and thats what the second inline fuse in the drawing references.

 

[BAD ORCA]

I'm not sure why you would want to do that. I wired mine the way the manufacturer's wiring diagram indicates. The "FUSE POSITIVE FEED" on mine is the fuse at the battery and is MUCH higher current than would be appropriate to protect the bilge pump and its wiring.

You could use external circuit protection but why not use the one supplied with the switch? If the fuse were to blow, that would be the obvious place to check first, not trying to trace to some other location.

I see Dave beat me to it. It looks like we are saying essentially the same thing.

I assume this is the switch:

https://d2pyqm2yd3fw2i.cloudfront.net/files/resources/instructions/9838.pdf

The concern is wire size. If fuse at the main panel is sized for the smallest diameter wire in the circuit the panel fuse could be omitted. However, for the small cost of the fuse, I wouldn't eliminate it. The fuse will give an added layer of protection that is more easily accessible than a fuse at the main panel and would allow you to use a larger wire from the panel to the switch to reduce line loss before using a smaller wire from the switch to the pump.

The risk for the pump is something jamming the pump causing the pump to short out or overload. In that case the shorter the distance to the fuse, the better.

The only downside I see to using the fuse is having one more connection in the circuit, that seems to me to be a minor concern.

To try and save space so i can fit all three bilge switches on one panel that has limited space. I would use a Blue Seas blade fuse block for fusing instead.

 

[BAD ORCA]

I assume this is the switch:

https://d2pyqm2yd3fw2i.cloudfront.net/files/resources/instructions/9838.pdf

The concern is wire size. If fuse at the main panel is sized for the smallest diameter wire in the circuit the panel fuse could be omitted. However, for the small cost of the fuse, I wouldn't eliminate it. The fuse will give an added layer of protection that is more easily accessible than a fuse at the main panel and would allow you to use a larger wire from the panel to the switch to reduce line loss before using a smaller wire from the switch to the pump.

The risk for the pump is something jamming the pump causing the pump to short out or overload. In that case the shorter the distance to the fuse, the better.

The only downside I see to using the fuse is having one more connection in the circuit, that seems to me to be a minor concern.

Yes thats the one. My positive feed wire would be 10GA only about 8' from fuse block to switch. This feed wire would be connected to a Blue Seas blade fuse block. I would use a 15A blade fuse instead of the 15A glass fuse. So the wire would be fused at the source and then travel directly to the switch bypassing the glass fuse. Thats the idea anyways, so the pump is still correctly fused according to the pumps specified fuse size im just moving it further away from the switch essentially.

 

[BAD ORCA]

maybe i can do a wiring diagram if im describing it in a confusing way.

 

[dlochner]

maybe i can do a wiring diagram if im describing it in a confusing way.

No need for me, I understand what you're doing.

 

[BAD ORCA]

No need for me, I understand what you're doing.

Thanks, after re-reading your first post, i think i will keep the glass fuse and wire it the way it is in the diagram. This way the pump wires will be closer to the fuse in case the pump jams. If i bypass the glass fuse at the bilge switch, any fault current that would trip the fuse would have to travel a longer distance to blow the fuse. I'm not sure how much of a difference it makes in reality but better safe than sorry. I'll find another location for the third pump switch.