Archive for the ‘Corrosion’ Category

Marine electrical questions?

June 28th, 2010 by Kevin Hannula

Marine Ac/Dc attempts to answer your questions about boat wiring and marine electrical techniques, concepts, and products. We get lots of mail from folks in mid-project or who are just curious about their boat’s electrical setup.

There are loads of post already on the site which we hope you will browse through. If you’re trying to track down info about a more specific category, please use the search box in the upper right of this page or check out the list of various subjects farther down on this page.

If you aren’t able to find the info that you need to complete your particular boat wiring project, please send us an email at boatwiring@gmail.com.

Thank you for visiting. We look forward to hearing from you and hope that you will be able to come back often.

Posted in Battery Charger, Battery Switch, Boat Wiring, Bow Thruster, Circuit Protection, Corrosion, Cruisers, Gauge Panels, Harnesses, Marine Electrical, Navigation Lights, Pontoons, Runabouts, Signaling Devices, Switch Panels, Testing, Trolling Motors, Uncategorized, VSR, Wipers | Comments Off

O’Day Dilemma

November 14th, 2011 by Marine Ac/Dc

Hello Kevin,

My boat wiring question is:

I have a 1979 37′ O’Day sailboat, with an Aft Cabin with the original 4 breaker terminal mounted on the locker.

When I bought the boat in 2000, I replaced the existing Loran with radar and wired it into the panel where the Loran had been and added a VHF radio to the back of the panel. Both have individual fuse protection. O'day Sailboat

Everything has worked fine until a few weeks ago when I noticed I have no power to the panel – cabin lights, engine room light, radar, radio, and autopilot do not work.

Both the positive and negative lines from the main power source in the forward part of the boat were tested by me and tested good.

I was told that it could be a ground problem. I looked at the negative marine electrical bus bar inside the locker and what is there are the negative wires from the accessories and the negative wire from the main bank in the forward part of the boat. There was also another 10 gauge wire but not attached to anything.

Should there be a ground wire attached to the buss bar to the engine and could this wire be my problem in that it somehow become disconnected?

I installed a new six breaker panel replacing the original; I installed a new 30 amp terminal (6 terminals) inside the locker and ran each accessory positive to it and then from there to the panel; Each accessory negative goes directly to the to the bus bar along with the 10 gauge negative wire from the main power source. The new panel has a negative bar which I also attached to the bus bar.

I then turned on each switch and they all light up meaning power is there. But when I turn on any of the accessories at the actual device they do not work and all the panel lights go off. When I turn off the individual accessory the panel lights will go back on. This happens with each item- cabin lights, engine room light, radio, radar, auto pilot.

Can you help me?

Confused

Jordan

Hi Jordan,

The problem is either in the feed wire or the ground wire.

The best way to find your problem is to test voltage levels when the system is under a load.

The panel indicator lights will initially turn on because the low current draw of the lights induces a small voltage drop in the wire. When you turn on a higher draw device, the voltage drop increases and the light turns off.

You will probably find a bad cable connection or hidden splice.

Hope this helps,

Kevin

Thank you for your response.

While waiting to hear back from you, I continued to investigate the problem.

Although I found numerous other problems as the O’Day has the original wiring, the cause for the failure was due to corrosion inside the positive wire where it entered into the front panel for power. As I tried to pull the wire to locate it, it broke off and was corroded inside the insulation. The joys of an old boat.

I have rewired the entire aft by replacing all the wires and panel and everything is back in order.

Regards,

Jordan

Posted in Anchor Lights, Battery cables, Boat Batteries, Boat Wiring, Circuit Protection, Corrosion, Cruisers, Galley, Gauge Panels, Ground Issues, Harnesses-Dash, Harnesses-DC, Marine Electrical, Masthead Lights, Sailboats, Switch Panels, Testing, Voltmeter | Comments Off

Add Isolator?

July 25th, 2011 by Marine Ac/Dc

Kevin,

I have ordered the Easy Add Shore Power AC system that (I’ve heard) you helped design for EzAcDc.EzAcDc offers a complete AC shore power system that makes your boat wiring project easy.

Our sailboat will be in a marina. I am assuming that most of the neighboring boats will be on shore power. I know I am planning on leaving mine on shore power to recharge the batteries during the week.

Does the Shorepower kit include a galvanic isolator, or is this something that I should add to the system?

Thank you.

Paul

Hi Paul,

The Shore Power System sold on our partner site does not include a galvanic isolator.

If galvanic corrosion is an issue in your marina, I would consider adding one to your boat wiring. The new “fail safe” units are easy to install. They simple go in-line in the green wire between the shore power inlet and the ac panel.

Thank you,

Kevin

Posted in AC Wiring, Boat Wiring, Corrosion, Galvanic Corrosion, Ground Issues, Marine Electrical, Shore Power | Comments Off

Houseboat Grounding

May 31st, 2011 by Kevin Hannula

Kevin,

I have questions on grounding both the 12 volt and 120 volt marine electrical on a houseboat. I have read the old threads regarding this matter but I am still thoroughly confused. Sorry that my post is long, but I am trying to explain clearly but simply:Boat Wiring Store has marine electrical products for your boat wiring project

Here is my set up:

The boat is 1976, steel hull. It has a shore power connection but because I am on a permanent mooring I do not connect to marina’s shore power.

Here are the original marine electrical systems and the boat wiring:

  1. 12 volt starting battery. Hot goes to engine starter and Negative cable on this battery is also landed at the engine. In looking how the engine is mounted, I don’t think that the engine (outboard) is isolated from the steel hull / frame.
  2. 12 volt house power: hot and negative battery cables go to marine electrical bus bars for each. These bus bars (hot and negative) then go to my 12 volt distribution panel, and to my 12 volt stereo/amp system. This 12 volt house system is not grounded anywhere that I can see. Question: Should it be grounded?
  3. 120 volt AC shore power system: Plug connection goes to a distribution panel. Typical 3 wire set up: Hot (black), Neutral (white), ground (green). I have not looked to see if the ground or neutral buses in this distribution panel are grounded anywhere on the boat. I don’t think it is, but I need to look again. Question: Should this be grounded? Because I am on a mooring, not in a slip, I never connect to actual land based shore power. When I do use this connection it is via my own portable generator on the boat. Fire up the genset, run a 30A shore power cord from gen. to shore power plug.
  4. New installation: I have connected a small 700W inverter from my 12 volt system just to run a few items (tool chargers, 120 volt rope lights, etc). The inverter has 2- 120V receptacles, no hard wire 120V. In the past I have plugged in an extension cord from the inverter to my rope lights. But, now I want to connect my rope lights through a permanently wired receptacle. I connected a 3-prong utility type cord (male plug on one end and open wires on the other). Intent to be to run this cord into a J-box where I could then run in conduit and wire to a switched receptacle for the rope lights. Funny thing is that when I checked the power coming from the 120V cord I get the following readings:
    • hot – ground: 110V
    • neutral to ground: 95 – 105V

    5. Is this correct? Shouldn’t this be 0 volts?

Everything works fine, but is this set up correct?
My biggest questions are: How should 12V system be grounded, How should 120V shore power be grounded (even though it doesn’t go to land based source), and is inverter power with current going through neutral correct?

Thanks very much for any help or clarity you can provide.

Paul

Hi Paul,

Regarding each of your boat wiring questions:

  1. You are correct. The engine is not isolated.
  2. The negative from your house battery should be tied to negative on your starting battery.
  3. Your AC ground and DC ground need to be connected to give a low resistance path to ground in the event of a major fault.
  4. Should be 0 volts.  Neutral and ground should be tied together at the inverter.
  5. AC ground should be connected to DC ground.  You should have a voltage reading of 0 Volts between AC ground and AC neutral.

I hope that this is helpful.

Kevin

Posted in AC Wiring, Battery Charger, Battery Switch, Boat Batteries, Boat Wiring, Circuit Protection, Corrosion, Cruisers, Galvanic Corrosion, Generator, Ground Issues, Marine Electrical, Shore Power, Voltmeter | Comments Off

Bronze is the new black?

March 21st, 2011 by Kevin Hannula

Hello Kevin,

I have a 30 foot Mainship in a slip in San Diego.

I recently noticed that my raw water strainer and my fresh water strainer – both bronze – are turning blackish in color. I have owned the boat for four years, do all of the regular maintenance myself and have not seen this before.

It also seems like I am going through zincs much faster since I got into this marina.

Do you think it is because I do not have a galvanic isolator in my marine electrical setup? Guest galvanic isolator

Thanks for your help.

Tim

Hi Tim,

A galvanic isolator should slow down the corrosion, but it may not solve everything.

In some hot marinas, it is possible to have the corrosion problems that you are seeing even with a galvanic isolator. That is, your boat may be parked in the middle of a large galvanic cell and may corrode even though you have a GI. Luckily, this situation is rare.

I would definitely recommend adding a galvanic isolator to your boat wiring as your first step.

I hope that this helps.

Kevin

Posted in AC Wiring, Boat Wiring, Corrosion, Cruisers, Galvanic Corrosion, Marine Electrical, Shore Power | Comments Off

Hull Ground?

February 28th, 2011 by Kevin Hannula

Hi Kevin,

My aluminum boat wiring has the negative returns and negative side of the battery all tied to the hull.

I would like to isolate the negative return and run all negative returns to the battery with the hull isolated.

My question is: What do I ground the aluminum fuel tank to? It is connected to the hull.

Thanks,

Scott

Hi Scott,

Grounding to an aluminum hull is un-avoidable. Some components just end up being connected. You are actually at risk of even greater galvanic corrosion if the hull is not tied to the negative side of your system.

I would recommending running grounds for all components and not using the hull as a conductor. To comply with the USCG requirements, the metal components on your fuel tank (the tank itself) need to be connected to the boat’s DC negative ground also.

Hope this helps,

Kevin

Posted in Boat Wiring, Circuit Protection, Corrosion, Cruisers, Galvanic Corrosion, Marine Electrical, Navigation Lights, Pontoons, Runabouts, Signaling Devices, Switch Panels, Testing | Comments Off

Six batteries to ground plate?

November 8th, 2010 by Kevin Hannula

Sir,

My marine electrical system has two 12 volt batteries in series and four in parallel.

Should I ground each boat battery (each negative of each battery) to my Guest Dynaplate – or just the negative one used in the end run?

Also, any problem with using the same plate for multiple voltage grounding (i.e. 12v, 24v etc.) ?

Thanks in advance

James

Hi James,

  • If your two 12 volt series batteries are only used for a trolling motor and not connected to any common charging system, I would completely leave them off of the Dynaplate – just run a ground wire from the ground bus to the dynaplate. Run a battery cable from the ground bus to each battery negative in the four in parallel pack and limit the boat wiring connected to each individual battery.
  • If you have a charging system similar to the BEP Trolling Motor VSR – do not connect the grounds to the Dynaplate.
  • If your four in parallel pack battery ground is already connected to one of the two 12 volt battery grounds, it is already tied to the Dynaplate.
  • If you want to keep the parallel batteries connected to the series battery, I would run a battery cable from your ground bus to the negative on the first battery in series. I would call battery #1 the one that has a negative cable connected to your trolling motor (or other 24 volt device) and the positive cable connects to the negative of battery 2. DO NOT run a cable from the negative of battery 2 of the 2-12v series batteries to your Dynaplate. This will create a dead short with no circuit protection and cause a fire.

Hope this helps,

Kevin

Posted in Boat Batteries, Boat Wiring, Circuit Protection, Corrosion, Cruisers, Marine Electrical, Voltmeter, VSR | Comments Off

Galvanic Isolator Boat Wiring

October 25th, 2010 by Kevin Hannula

Hello Kevin

I just purchased an “Easy Add AC” marine shore power kit.

A friend says that I should also have a galvanic isolator in my marine electrical system.

It looks like I should place the isolator in line with the ground in between the new system’s shore power inlet and the 120v panel. What is the best method of accessing the ground wire for this purpose? I assume the green ground wire coming off the 120v panel goes to the DC ground buss despite using the isolator?

Please advise.

Thanks,

Chip

Hi Chip,

Your galvanic isolator needs to go in the green grounding wire between the AC inlet and the AC panel. You will need to cut back the white insulation on the 10/3 boat cable to access the green wire. The easiest place to add the GI to your boat wiring will be next to your new shore power inlet. Remove the cover on the back of the inlet to access the green wire.

The green wire that comes off of the back of the AC panel goes to the DC ground bus.This provides a low resistance path to ground (required by USCG) in case of a major AC fault.

Please let me know if you have any other questions.

Thank you for your order,

Kevin

Posted in AC Wiring, Boat Wiring, Circuit Protection, Corrosion, Cruisers, Marine Electrical, Shore Power, Testing | Comments Off

Decipher the drawing?

October 18th, 2010 by Kevin Hannula

Hi Kevin,

I’m working off the attached diagram and am wondering if you know where I can get a diagram for the boat wiring connections in the dash. I’m using a stern drive drawing were I will be bi-passing the ECM and Trim components. I swapped a 4.3 into a Shamrock (Inboard)

I can probably figure out most of the plug connections. My concern is the Red/Purple and the Purple wires on the Plug. Where are they connected in the dash?Shamrock boat wiring

Thanks for any Help

Phil

Hi Phil,

The Red/Purple is the ignition feed wire. It provides constant power to the ignition switch. This is usually connected to the B post on your key switch. I would recommend adding an in-line fuse or circuit breaker near the key switch. According to your boat wiring diagram, it is protected by a 50 amp breaker on the engine and most key switches are only rated at 15 amps.

The purple wire is the ignition wire. This is usually connected to the I post on your key switch. Your instruments are also powered by this wire.

Hope this helps,

Kevin

Posted in Battery Charger, Battery Switch, Boat Wiring, Bow Thruster, Corrosion, Cruisers, Harnesses, Horn, Ignition Switch, Marine Electrical, Navigation Lights, Signaling Devices, Switch Panels, Trim, Voltmeter | Comments Off

Boat harness = Beetle harness?

August 11th, 2010 by Kevin Hannula

Kevin,

I have been thinking about corrosion, road salt and +/- ground systems in relation to rust and basic electrolysis. It is interesting that marine electrical has already addressed these kind of issues.

So, would it be possible to build a custom wiring harness for a VW Beetle that would bypass the body ground a’la boat wiring?

Thanks,Malcolm Buchanan crossing Irish Sea

Scott

Hi Scott,

Boat wiring harnesses avoid body grounds for two reasons:

  1. To minimize galvanic corrosion
  2. Most boats are not made completely from conductive metal

If you built a harness for your Beetle, you could certainly run individual grounds back to a ground bus instead of using the car body/frame. It would nearly double the amount of wire required for your project, but you would potentially eliminate electrical circuit problems caused by corrosion.

Kevin

Posted in Boat Wiring, Corrosion, Cruisers, Harnesses, Marine Electrical, Runabouts | Comments Off
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