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I got an used autopilot for my Catalina 27 (wheel). I don't have a dedicated switch on my fuse panel for my instruments. I will add that in the near future when I replace the non working depth and speed. Today I installed the autopilot and wanted to put it on a switch in the cockpit. I have attached a photo of the switch. I am running directly from the battery to the switch, then off the switch to the control head, with a fuse inline. I connected the negative to the battery and then connected the positive. All worked as it should, except I realized the switch was in the on position. I flipped the switch off and went to put the positive back on and it created a large spark. It then removed the negative, installed the positive and tried to install the negative and had the same issue. The ring terminal even tried to weld to the battery post.

What am I doing wrong?
 

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Sounds like your switch is giving you a dead short...check it with a meter if you have one...even new ones can be faulty...
 

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Um, you just wired that switch to short circuit your battery with no fuse. That is very dangerous, remove it immediately, get new wires and a new switch, and read how to wire the switch properly. Don Casey has a good boat electrics book.
 

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I got an used autopilot for my Catalina 27 (wheel). I don't have a dedicated switch on my fuse panel for my instruments. I will add that in the near future when I replace the non working depth and speed. Today I installed the autopilot and wanted to put it on a switch in the cockpit. I have attached a photo of the switch. I am running directly from the battery to the switch, then off the switch to the control head, with a fuse inline. I connected the negative to the battery and then connected the positive. All worked as it should, except I realized the switch was in the on position. I flipped the switch off and went to put the positive back on and it created a large spark. It then removed the negative, installed the positive and tried to install the negative and had the same issue. The ring terminal even tried to weld to the battery post.

What am I doing wrong?
Looks like you have both positive and negatives on the switch - in the on position a dead short. Switches only control the positive wire. The only time a negative is used on a switch is if it has an indicator light that needs it.

You should have the negative going to the autopilot. The positive goes to to one side of the switch and from the other side to the autopilot. Fuse the positive close to the battery.
 

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I got an used autopilot for my Catalina 27 (wheel). I don't have a dedicated switch on my fuse panel for my instruments. I will add that in the near future when I replace the non working depth and speed. Today I installed the autopilot and wanted to put it on a switch in the cockpit. I have attached a photo of the switch. I am running directly from the battery to the switch, then off the switch to the control head, with a fuse inline. I connected the negative to the battery and then connected the positive. All worked as it should, except I realized the switch was in the on position. I flipped the switch off and went to put the positive back on and it created a large spark. It then removed the negative, installed the positive and tried to install the negative and had the same issue. The ring terminal even tried to weld to the battery post.

What am I doing wrong?
You wired a dead short!!!!

A switch is intended to OPEN/BREAK a positive wire and gets inserted into the positive wire (would do the same on negative but in the US we open positive)..

You wired a dead short by connecting battery B+ to battery B- when the switch is made....

ANY WIRES CONNECTED TO THE BATTERY NEED A FUSE WITHIN 7", OR AS CLOSE AS POSSIBLE, TO THE BATTERY + TERMINAL!!!!

Time to get Charlie Wings book, Boatowners Illustrated Electrical Handbook - Second Edition;)
 

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Hey,

No offense, but you don't know what you are doing.

Please either get a book. study, learn, and practice, or hire a professional and watch what he does.

Doing things incorrectly can be dangerous and expensive.

Barry
 

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What kind of pilot is this? Some pilots have an on/off feature that doesn't involve the battery wires. The on/off switch is wired to 2 terminals on the pilot.
 

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It looks like you're in way, way over your head on electronics. I say this without judgement - it can be hard to know what you don't know when you're a novice - but wiring a switch is about as basic as things get. You probably should stop before something catches fire, and find a way to learn more about DC electronics. I'd suggest some automotive wiring; at least if your car catches fire (mine did!) you can walk home.
 

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So you own a fire extinguisher and have plenty of insurance right?

Good, you are going to need it. Wow.

Hopefully your neighbours don't see what you are doing.
 

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Correct me if I'm wrong, but isn't that the purpose of a SPST switch?
To give a dead short? No.

A SPST switch is designed to connect the incoming wire with the outgoing wire. Both wires are POSITIVE.

The op connected a positive to a negative and that is a dead short. No different than tossing a crescent wrench across the battery posts, he just used small gauge wire that burns faster!
 

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Discussion Starter · #13 ·
Hey Bore, thanks for using your very FIRST post replying with a non answer. Too bad we are not neighbors. You could watch me everyday. Keep up the clever conversation.

Thanks to everyone with helpful comments.
 

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Learning about electronics

Hey,

It occurred to me that my original response could have been more helpful. In case someone wants to learn more about basic electronics, there are number of TOYS that can help.

My dad was always buying things like this for my son:
50-in-1 Project Lab (eleep-50) Elenco Electronic Science Kits Non Solder

We would play around with them and you really can learn a lot about basic electronics.

Of course, there is a lot more information in books, but this is a cheap way to learn about wiring, switches, diodes, LED's, etc.

Barry
 

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It was a mistake and you're still alive, if the auto polite is still ok, no harm, no foul and you learned something...

I'm glad people bring these issues to the forums, it helps me learn...
 

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To give a dead short? No.

A SPST switch is designed to connect the incoming wire with the outgoing wire. Both wires are POSITIVE.

The op connected a positive to a negative and that is a dead short. No different than tossing a crescent wrench across the battery posts, he just used small gauge wire that burns faster!
Of course. Thats exactly what it is. So which side is which? Im having trouble figuring out what one is the outgoing..... Is it labeled?

And yes, my post was rather non answer, but if you cannot figure out a switch, maybe it is something better left to the professionals.

There are plenty of other projects you can do that leave the rest of the people moored near your boats in less jeopardy when you do it horribly wrong.

What kind of draw is your autohelm using, is your wire sized accordingly? Where is the overcurrent device? These are factors to be concerned about when doing electrical work, having both sides of the battery hooked up to either side of your switch suggests that you haven't thought about these other concerns.
 

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On a SPST switch it doesn't matter. You are connecting one side with the other.

This is a SPST



This switch is a SPDT and the center is the input.



Charlie's book could turn out to be a best seller.
 

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On a SPST switch it doesn't matter. You are connecting one side with the other.

This is a SPST



This switch is a SPDT and the center is the input.



Charlie's book could turn out to be a best seller.

Forgot the sarcastic font again. Sigh.

Dead short was the wrong term as it referred to a circuit, I rescind that statement.

What I was so awkwardly trying to get at was that it is just a basic switch, there are no options, off no continuity, on continuity. It just closes a gap, there are only two ways it can fail, open or closed. If you put that between the poles of a battery, and have to ask a community forum what is wrong, maybe electrical just isn't for you.

With another user suggesting they test this switch as it could be broken from factory, when the OP has :

A: Proof it works (almost melted ring terminal to battery)
B: Clearly no clue what he is doing.

This only furthers to confuse the problem, people who don't know how to troubleshoot telling people that have no knowledge or concept what to do.

It isn't that difficult, but the consequences for failure can be dire.

If you had absolutely no clue how to put in a thru hull would you just come and drill a hole in your boat?

How many fires on board are attributed to shoddy electrical?

Not only are you risking your personal health and safety, but you risking damage to other peoples property as well as their health and well being. Is that really worth not learning how to do it right? Or pay someone to do it?

When your boat burns down and writes off mine next to it and all I receive for that is actual cash value for my 5ksb? Thanks, I really appreciate it. Didn't work hard for that at all.
 

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My suggestion to test the switch was so that in doing so he would find out what he was doing wrong on his own ...saying someone is stupid really doesn't help...
 
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