New to Electrical

CeeJ1791

Seaman Apprentice
Joined
Aug 16, 2017
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44
I recently obtained a 1976 Starcraft Super Sport 16. The price was too good to pass up so I knew there would be some projects. I quickly learned that all the accessories worked intermittently. At first I thought it may be a battery issue but now I'm thinking it may be a wiring issue. The current setup has a three toggle switch dash (on-off) with a push button for the horn (external) built in. None of the switches were labeled so it took some trial and error to figure them out. SWITCH ONE: Bilge Pump UP for ON. SWITCH TWO: Bow lights DOWN for ON. SWITCH THREE: either stern lights or cabin lights (both of which are wired but neither are functional. Horn button rarely works and when it does the horn is very weak. It looks as if all accessories are wired to the switch and then to the battery (located below the transom); no fuses, no breakers, no battery off switch. I should make note that this is a single 12 volt deep cycle battery setup with the ignition and fish/depth finder also wired directly to the battery. I'd like to replace the switch panel (which is pretty corroded) to something with a little more capacity (I'd like to get the stern light and cabin lights functional, add the fish finder, and a possibility of adding a radio in the future). I'm pretty novice when it comes to electrical technicalities so any advice of where to begin would be great.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
You need ti do some readung on "basic low voltage" circuitry. You then need to buy a hand held VOM (volt-ohm-mulliammeter) if you intend to do any electrical work. We cannot teach you this stuff in a few lines if text.
 

CeeJ1791

Seaman Apprentice
Joined
Aug 16, 2017
Messages
44
You need ti do some readung on "basic low voltage" circuitry. You then need to buy a hand held VOM (volt-ohm-mulliammeter) if you intend to do any electrical work. We cannot teach you this stuff in a few lines if text.

I've been familiarizing myself with the basics and have a vom. There are so many different wiring diagrams out there, just trying to get pointed in the right direction for my needs. If I get a dash panel with built in breakers do I need a seperate breaker box? A lot of schematics show multiple negative bus bars and fuse blocks, whats the reasoning for this?
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
:welcome: board CeeJ1791 to ibots. Great to have you join us...

First thing is, don't be ashamed to be a novice with electrical circuits. We all had to start some where and there is nothing shameful about that.

Since you stated you do own a VOM meter, then you are all set to go. First thing you need to understand is every circuit in your boat has to be either fused or circuit breakered. Now that option is entirely up to you as to which way you want to go. There are pro and cons to each setup. So read up on them and make your choice.

A typical setup on a boat has a fused/CB (circuit breaker from now on) at the battery with both a heavy gauge red and black wire going to where every you want your accessory panel to be. At the battery, most fuse/CB the red wire coming off the battery and just a straight black wire without a fuse or CB. And you add up all the current your circuits will need and install that fuse or CB accordingly at the battery to cover everything.

Those heavy gauge wires will go to the helm panel area. At the helm there is usually a break out strip (terminal block) for both the red (positive) and black (negative) wires. And then you can tap off those power strips (terminal blocks) to go to each circuit you are installing.

If you want a circuit for the lights, you tap off the red strip and run a wire to the panel and either a fuse holder or CB to the switch and then to the lights on the boat. The black wire will come from the lights back to the negative strip. That completes one circuit. And you fuse or CB the circuit according to the light current needs. I.E. if the light need 3 amps, I would use a 5 amp fuse or CB. That way you will not blow a circuit when initially turned on. In rush current some times is a little bit higher then the running current. So always install a fuse or CB just a little higher then run current needs. But you also have to select the red and black wires (wire gauge size) for that circuit to handle the current as well. There are charts everywhere on the net to allow you to select the proper gauge sizes for your circuits. Usually most people go 16 gauge or even 18 gauge depending on the length for most lightly use circuits. But you can confirm that from the charts.

And buy marine quality wire when you buy the wire. It is tinned and will hold up longer for boat wiring. It isn't any harder to buy or cost anymore. Use the proper wire and enjoy a trouble free setup. Every additional circuit follows that same layout. Now you know how to do it. So make a wiring diagram as you add new circuits for future needs. Simple if you work one circuit at a time. And you did it yourself!

If you need any addition info, ask your questions on here. There are tons of great people here to help you. JMHO
 

CeeJ1791

Seaman Apprentice
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Aug 16, 2017
Messages
44
Thanks GM for the advice. I've been watching a ton of 12v circuit vids on YouTube and learning a lot. I think I'm going the CB route apposed to the dash panel with built in fuses. Still trying to distinguish between the different types of bus bars (100a vs 150a) and what I need for my setup. I found a pretty simple schematic online that I think will fit my needs. If I can figure out how to post a pic I'll upload the schematic.
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
Thanks GM for the advice. I've been watching a ton of 12v circuit vids on YouTube and learning a lot. I think I'm going the CB route apposed to the dash panel with built in fuses. Still trying to distinguish between the different types of bus bars (100a vs 150a) and what I need for my setup. I found a pretty simple schematic online that I think will fit my needs. If I can figure out how to post a pic I'll upload the schematic.

Cee, for easy access, you can always install CB's on the dash panel for each circuit. That way if you do pop a breaker, you can easy see which one and simply push it back in to reset. Then you don't have to crawl around under the dash or any place else. Here is are a couple pictures of the helm panel I made for my boat project, I too used CB's.


Plates - (14).JPG
Plates - (15).JPG

You can see the CB's above the switch for each circuit. Just an option, not saying that is the only way to make your panel layout. JMHO
 

CeeJ1791

Seaman Apprentice
Joined
Aug 16, 2017
Messages
44
:

A typical setup on a boat has a fused/CB (circuit breaker from now on) at the battery with both a heavy gauge red and black wire going to where every you want your accessory panel to be. At the battery, most fuse/CB the red wire coming off the battery and just a straight black wire without a fuse or CB. And you add up all the current your circuits will need and install that fuse or CB accordingly at the battery to cover everything.

Those heavy gauge wires will go to the helm panel area. At the helm there is usually a break out strip (terminal block) for both the red (positive) and black (negative) wires. And then you can tap off those power strips (terminal blocks) to go to each circuit you are installing.

I plan on using 16 gauge to run from the block to the switches and then to the accessories, but what gauge do I need to use to go from the battery to the block?

Also, I currently have a one battery setup (my trolling motor has its own battery near the bow) do i need to install a battery switch? If I do should i get a 2 battery switch in case I ever decide to go duel batteries?
 

dennis461

Chief Petty Officer
Joined
Aug 11, 2011
Messages
516
Battery to block wire should be #12 or larger (#10, #8) for both positive and negative
Depends on how long a wire run and how much you actually have connected
A breaker panel is the way to go, on my boat I have two exceptions, a matter of personnel preference.
My engine bay fan is separate fuse and switch.
I like to turn the fan on before any other electric stuff.
Also, my VHF radio is fused, and no switch, I'd like it to work if all other stuff craps out.
 

CeeJ1791

Seaman Apprentice
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Aug 16, 2017
Messages
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Battery to block wire should be #12 or larger (#10, #8) for both positive and negative

Should there be an inline breaker in the run from battery to the breaker block? If so what size? 50amp overkill?
 

gm280

Supreme Mariner
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Jun 26, 2011
Messages
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As previously stated, the proper gauge depends on the total current draw from everything at the helm panel AND the length of the run from the battery to the helm. With that stated, I would install a breaker right at the positive terminal at the battery as well. 50 amp could work if you are drawing a lot at the helm. Add up all the circuits and then go just a little higher for the battery breaker. And use wire gauges the same for both the positive AND negative wire runs just like "dennie461" stated about. Because for every circuit you have to have a return that is just as capable to carry the current to and from the battery as the positive wire.

The reason for that battery breaker is just in case the main wires you will run from the battery to the helm panel even chaffs and possibly shorts. It will protect the battery, the wires and most importantly the boat from fire. One thing you have to remember, if the boat ever catches fire, there is no place to run on the water. So proper wiring IS very important. Hope that helps some. JMHO
 

edit-Insert

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Joined
May 22, 2017
Messages
34
Just an fyi... Do this test on a bench with an unused 12v device... Preferably a led light. Put a switch on positive. Notice when flipping that switch the light takes a bit to go off. But if you put the switch on the negative lead it goes off more quickly. That's why I switch and fuse my negative terminals. This is especially true in My profession working with magnetic locks. Negeative must be switched on mag locks or you are creating time lost on an emergency egress situation. So all electronics switched and fused on my boat have been switched negative and I've had zero problems.
 
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edit-Insert

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May 22, 2017
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The results of that test are much more apparent if the device you are testing has a series of capacitors and resistors.
 

dingbat

Supreme Mariner
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Nov 20, 2001
Messages
15,413
No problem putting redundant fuses on ground side, but negating fuses on the positive side is not only a violation of ABYC standards, but potentially dangerous on a boat where all circuits connect to common ground.

The reason to fuse on the supply side, is that if the grounding from the battery to the boat frame/engine should fail, every negative lead, and any piece of metal for that fact, becomes a possible (unprotected) return path to the battery for the boat.

With no fuse on the supply, wire shorts to unprotected ground, insulation begins to melt, fire ensues
 

CeeJ1791

Seaman Apprentice
Joined
Aug 16, 2017
Messages
44
Let's talk wire colors... I don't have any gauges, as long as I keep everything constant throughout does it matter what color wires I use? (Ie yellow for negative green for positive)
 

...bill

Seaman Apprentice
Joined
Sep 5, 2016
Messages
42
Have done a lot of wiring on boats and learned pretty much from zero.
A few suggestions:
1. It's your boat, and you can wire it any way you want. However, there are many good reasons to use "best practices". Most boat fires are caused from electrical issues. Most intermittent or non-working equipment issues are caused from bad electrical connections.
2. Best practices are outlined by the ABYC. It can be daunting to decode all of the raw specifications, but there are plenty of good practice guides available. Bottom line, you want the electrical system on your boat to be safe AND reliable.

Maybe the best reference for anything electrical/mechanical on boats is this book from Nigel Calder:
https://www.amazon.com/Boatowners-Me.../dp/0071432388

3. Visit the Blue Sea Systems web page. Not only do they sell good stuff, but they have a free wiring calculator tool. Simply plug in how much current (amps) your load uses and the length of the run. Poof, the tool will tell you what wire size to use to be compliant with ABYC rules. Don't forget you need the the round trip wire length. I have no affiliation with Blue Sea Systems.
4. You need a way to disconnect the battery in case of an emergency. Usually this means installing a battery disconnect switch close to the battery.
5. Fuses are primarily used to protect the wiring. You need a fuse close to the battery to protect the wire up to your helm panel. Starter motors are exempt from this, but every other positive wire should have a fuse or a circuit breaker. Even the circuit breaker in a panel is there to protect the wire to the appliance/device. Most equipment will require another fuse for equipment protection. Make sure to wire those in. It may make sense to locate the equipment fuse near the equipment.
6. Wire type. Marine use is a hostile environment for wiring. The good stuff is stranded tin plated copper wire. Ancor is pretty much the major supplier of this. If you have an engine compartment, you need to be aware of the temperature rating of the wiring insulation. Don?t use house wire for wiring a boat.
7. Wire color. I?ve seen many guys use whatever they have laying around. Sure, the electrons don?t care about the color the insulation. You may completely understand your wiring and what goes where right now, but what about in 2 years? What if someone else ever works on your boat? Bite the bullet and use the proper wiring colors for the major circuits:
12V DC positive RED
12V DC negative YELLOW (black is OK, but use yellow for anything new)
120V AC hot BLACK
120V AC neutral WHITE
120V AC safety ground GREEN or GREEN/YELLOW
Bonding wires GREEN or GREEN/YELLOW
8. Wire connections. No wire nuts on a boat, anywhere, ever. Crimp connections are the standard on boats, and they cause a lot of electrical problems if not done properly. You need both good quality crimps and a matching good quality crimping tool. I?ve found this to be the area of much voodoo when wiring boats. When you purchase crimps, there?s nothing about what tool to use. When you purchase a crimper, same thing. You aren?t going to find marine worthy crimps at Home Depot or Harbor Freight. Do some research or crimps will become your biggest headache. Just go here and read. http://www.pbase.com/mainecruising/wire_termination
Be prepared to pay for good tools and good crimps.

Please, don?t be intimidated. Like anything else, there?s a learning curve. After a few days of reading, you?ll be well on your way to doing a good job.

Best of luck,
?bill
 
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CeeJ1791

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