My wife and I recently purchased a 1976 O'Day 25. My question is this: Without any original documentation (e.g. wiring diagrams, etc.) how do I know what size fuses to use in the circuit panel? I blew the 5 amp fuse that was on the interior lighting circuit, and I would like to know what is the proper replacement size. Any guidance? Thanks in advance...
What size fuse?
- Thread starter Kevin 13837
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Why have a fuse
Power (Watts) = Current (I) * Voltage (V) P = IV How many watts does each device on the circuit consume. Your voltage is probable a 12 Volt battery. If you had a 5 amp fuse Watts = 12x5 = 60 watts The fuse protects the wires. The question is how thick is the wire. If the fuse is too big it will burn the wire before the fuse. The fuse also protects electronics. I would unplug equipment, put the 5 amp fuse back in and plug in equipment until the fuse blows to try and find the faulty circuit. If it blows over a period of time check equipment that gets hot.
Power (Watts) = Current (I) * Voltage (V) P = IV How many watts does each device on the circuit consume. Your voltage is probable a 12 Volt battery. If you had a 5 amp fuse Watts = 12x5 = 60 watts The fuse protects the wires. The question is how thick is the wire. If the fuse is too big it will burn the wire before the fuse. The fuse also protects electronics. I would unplug equipment, put the 5 amp fuse back in and plug in equipment until the fuse blows to try and find the faulty circuit. If it blows over a period of time check equipment that gets hot.
Wire load
I agree with TonyK. There is no direct answer. On a 28 year old boat there could be a lot of changes. Determining the specific needs of your circuits is the best way to go, rather than a stock answer. Also, if you inspect the wires at any junction, do they look silver and shiney (tinned wires) or oxidized copper? The original wire in your boat was un-clad copper. No good in a salt water environment. If your wiring has not been replaced since new, expect bugs and plan on running new wire for all the systems. Also replace any old light sockets, mast and running lights. Scraping the bulb contacts with a pen knife just doesn't cut it after a while. Notorious for failures on older boats. Two hours work for every hour of sailing.
I agree with TonyK. There is no direct answer. On a 28 year old boat there could be a lot of changes. Determining the specific needs of your circuits is the best way to go, rather than a stock answer. Also, if you inspect the wires at any junction, do they look silver and shiney (tinned wires) or oxidized copper? The original wire in your boat was un-clad copper. No good in a salt water environment. If your wiring has not been replaced since new, expect bugs and plan on running new wire for all the systems. Also replace any old light sockets, mast and running lights. Scraping the bulb contacts with a pen knife just doesn't cut it after a while. Notorious for failures on older boats. Two hours work for every hour of sailing.
A different suggestion
I'd recommend that you seriously consider changing the wiring. I bought the same year and model (mine is a centerboard model, but a '75 O'Day 25), and ended up rewiring everything. All of the lighting equipment has changed dramatically since the boat was built, and you'd also have the security of knowing exactly what type of wiring you have.
I'd recommend that you seriously consider changing the wiring. I bought the same year and model (mine is a centerboard model, but a '75 O'Day 25), and ended up rewiring everything. All of the lighting equipment has changed dramatically since the boat was built, and you'd also have the security of knowing exactly what type of wiring you have.
Thanks
Thank you for your responses! They have been helpful, and I'm sure I will have more questions in the future. Maybe I can even answer a few...
Thank you for your responses! They have been helpful, and I'm sure I will have more questions in the future. Maybe I can even answer a few...
help with wiring
Don Casey has a collection of sailboat do it yourself repair books. I just picked up the book for sailboat wiring and it's excellent. My O'day Tempest was built in the late 60's early 70's. When I purchased it, I had to tear all the wiring out, it was junk. I'm now adding all of the wiring back in and this book as been an extremely valuable resource, I highly recommend it. He will show you how to make your own wiriing diagrams, What size wire to use, amps to protect the wire based upon the usage etc. Definitely worth the $20.00. Best of luck. Kevin
Don Casey has a collection of sailboat do it yourself repair books. I just picked up the book for sailboat wiring and it's excellent. My O'day Tempest was built in the late 60's early 70's. When I purchased it, I had to tear all the wiring out, it was junk. I'm now adding all of the wiring back in and this book as been an extremely valuable resource, I highly recommend it. He will show you how to make your own wiriing diagrams, What size wire to use, amps to protect the wire based upon the usage etc. Definitely worth the $20.00. Best of luck. Kevin
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