OK to use larger fuse?

[lawrence_craig]

My anchor windlass fuse (100a) went today due to water intrusion into the remote.

I have a similar 125a fuse for short term replacement, will that be ok?

I understand that given the larger current protection, I risk damaging the windlass but unsure if 25a will make a significant difference.

I will obviously dry out the windlass remote but still a slight chance of it shorting again.

I also appreciate that some advice might be “don’t try at all” but my issue is I am anchored somewhere that a replacement 100a fuse isn’t readily available.

Thoughts?

[belizesailor]

Fuses are to protect the wires from overheating and starting an electrical fire. Thats the risk of a larger fuse or by- passing a fuse.

If you are somewhere you can get a new fuse then that is the best solution.

[Cheechako]

My windlasses had 150 amp , (one may have been 200 amp?) on 44 and 47 foot boats. So I would think you are good to go, but it's all about cable size and windlass amp draw, and continuous run time.
What windlass?

[Sailmonkey]

What wire size?

You may have sufficiently large cable to safely fuse for 125 amps

[lawrence_craig]

Originally Posted by Cheechako

My windlasses had 150 amp , (one may have been 200 amp?) on 44 and 47 foot boats. So I would think you are good to go, but it's all about cable size and windlass amp draw, and continuous run time.
What windlass?

It’s a Lewmar on a Bav 46 (2007)

[thinwater]

Commonly there is ALSO a breaker. Is this the case?

[lawrence_craig]

Unfortunately one didn’t come fitted but I think I will be fitting one as I don’t want to keep going through fuses!

[belizesailor]

Something like these are common. High AMP and resettable.

https://www.lewmar.com/node/11635

However, before you do anything else it would be best to determine existing wire gauge and length of run.

[Lake-Effect]

Originally Posted by lawrence_craig

My anchor windlass fuse (100a) went today due to water intrusion into the remote.

I have a similar 125a fuse for short term replacement, will that be ok?

I understand that given the larger current protection, I risk damaging the windlass but unsure if 25a will make a significant difference.

I will obviously dry out the windlass remote but still a slight chance of it shorting again.

I also appreciate that some advice might be “don’t try at all” but my issue is I am anchored somewhere that a replacement 100a fuse isn’t readily available.

Thoughts?

I don't understand how water intrusion into the remote could cause the main windlass fuse to blow. Full current does not go through the remote. Did the water jam the windlass on and the fuse blew when it failed to shut off after the anchor was fully retrieved?

You need the answer to this before deciding on the fuse thing. If the cause of the fuse blowing is known, and it wasn't because of a failing/shorting windlass, I would personally be comfortable with temporarily using the 125A fuse til you can buy a proper 100A fuse.

But answers first!

[Cadence]

Originally Posted by Lake-Effect

I don't understand how water intrusion into the remote could cause the main windlass fuse to blow. Full current does not go through the remote. Did the water jam the windlass on and the fuse blew when it failed to shut off after the anchor was fully retrieved?

You need the answer to this before deciding on the fuse thing. If the cause of the fuse blowing is known, and it wasn't because of a failing/shorting windlass, I would personally be comfortable with temporarily using the 125A fuse til you can buy a proper 100A fuse.

But answers first!

I had the same question. Short term 125A would be OK if the remote turns the winch off reliably when dry.

[blubaju]

Originally Posted by belizesailor

Fuses are to protect the wires from overheating and starting an electrical fire. Thats the risk of a larger fuse or by- passing a fuse.

If you are somewhere you can get a new fuse then that is the best solution.

Sorry, it is NOT that simple. Fuses MAY protect the wire, and fuses MAY protect an appliance. In case of an anchor winch it propably protects the winch as the wire is usually heavily oversized because of the voltage drop between battery and motor.


Next, achor winches run for short ime only, the wire will not really become hot, but the thin wires inside the motor are not protected against overload (pulling the yacht to the anchor or trying to break an anchor free. We as owners do not do that, but our guests?)


Anyway, if the alternative is bare wire, better use the 25% higher rated fuse and change at next opportunity, of course, your own risk, do not blame me ;-)

[Madehn]

subbing a bigger fuse without knowing the wire size or the amp capacity of the unit being protected is a really bad idea- you stand the chance of destroying an expensive piece of equipment or melting a wire. i agree that most wires to windlass are oversized but i also have seen installations where they used the smallest size possible trying to save money. You need to do more research prior to just putting in the larger fuse. sorry know that is not what you wanted to hear, but weigh the risk vs consequences vs benefits.

[kish]

Originally Posted by blubaju

Sorry, it is NOT that simple. Fuses MAY protect the wire, and fuses MAY protect an appliance. In case of an anchor winch it propably protects the winch as the wire is usually heavily oversized because of the voltage drop between battery and motor.


Next, achor winches run for short ime only, the wire will not really become hot, but the thin wires inside the motor are not protected against overload (pulling the yacht to the anchor or trying to break an anchor free. We as owners do not do that, but our guests?)


Anyway, if the alternative is bare wire, better use the 25% higher rated fuse and change at next opportunity, of course, your own risk, do not blame me ;-)

There is some confusion of the principles of circuit protection by blubaju

A fuse or circuit breaker by design is there to protect against an over current situation between the fuse itself and a load, in this case a windlass.

An over current situation arises when there is a fault downstream of the fuse, typically a short circuit in the wiring or burnout of the appliance due to overloading.
The wire size to a device is typically specified as 125% of the full load capacity of the largest appliance on the fused circuit with an acceptable full load voltage drop over the length of the wire from fuse to device.

The fuse protects against burning out the wire, avoiding the possibility of causing a meltdown of wire or fire.

[model 10]

[QUOTE=belizesailor;2932084]Fuses are to protect the wires from overheating and starting an electrical fire.



It's the insulation that catches on fire. The reason you can't use good Anchor wire in an airplane is the insulation is not fire proof. It's not that much more expensive to get wire that is safer. As usual, we get screwed.

[KP44]

Fuses and breakers protect the wiring; not the windlass. It is likely your windlass is wired with 1/0 or 2/0 cable, which will easily handle 120 amps.