Boat Wiring and Marine Electrical

Attwood offers the most complete selection of pumps and blowers for your boat wiring project

A complete selection of pumps and blowers are available for fishing boats, runabouts, cruisers, yachts, and commercial boats. All are tested and approved as standard equipment by leading boat manufacturers.

Bilge and Aerator Pumps

The Heavy-Duty 1700 and 2000 bilge pumps have established Attwood into the marine electrical market with value-loaded industrial-duty features and performance.

The Tsunami series of cartridge style bilge and aerator pumps are engineered for higher performance in the most service friendly design imaginable. Their cartridge style allows quick and easy replacement without the need to remove hoses or mounting bases.

Automatic Bilge Pumps

All boats over 20′ long with sleeping accommodations (excluding fold-out cockpit seats) should use automatic bilge pump systems. Non-automatic pumps drawing 12-amps or less can easily convert to automatic operation with an Attwood Automatic Float Switch (part number 4201 or 4202). Their Sahara Series automatic pumps are available in 500, 750 and 1100 gph capacity models. Bilge pumps are designed to exhaust standing water only. They are not intended to prevent rapid accumulation of on-board water due to rough weather, hull damage, and/or other unsafe navigational conditions.

Note: Bilge and aerator pumps must be lower than the source of water for priming.

Turbo In-Line Blowers

Attwood offers ventilation equipment and accessories featuring the revolutionary, patented Turbo In-Line Blowers for 3″- and 4″-diameter systems. Turbo blowers are the most dependable, efficient, and powerful in-line blowers on the market, designed using aerospace technology. The Turbo line also features the industry’s first water-resistant blower models, with durability proven in rigorous moisture tests and years of success in the field. Attwood offers Turbo water-resistant blowers with an unprecedented three-year limited warranty, and a one-year limited warranty for standard models.

Tsunami pumps are durable and designed to last, too.

The efficient design circulates water around the pump motor housing, helping to absorb the heat given off by the operating motor. Attwood uses the most advanced material available, including the best quality bearings and state-of-the-art brushes, alloys and magnets. Their patented shaft seal centers directly on the motor shaft, preventing leaks caused by misalignment.

Attwood’s exclusive molded two-wire seal is permanently fused to the insulation to prevent a leak path. And their wiring is caulked and tinned to eliminate wicking, prevent water damage and resist corrosion.

The Attwood Tsunami bilge pumps are available from the boat wiring specialists, EzAcDc.

Attwood presents the most energy efficient LED navigational lights in the world.

Through the use of proprietary optical design techniques, they’ve optimized their lens design to harness nearly 90% of all light being generated by the LED. In doing so, their line of LED series navigational lights exceed US Coast Guard requirements with the fewest and lowest watt LEDs of any navigational light manufactured today. Less energy used by navigational lighting means more energy available for powering your boat and enjoying time on the water.

As the emerging leader in the marine lighting design, Attwood understands the demands of the marine environment. Completely sealed LED units resist water intrusion, electrostatic discharge, (during assembly) vibration and ultraviolet light (UV) radiation.

Reverse polarity protection has been added to eliminate potential mis-wiring damage during installation. Their LED navigational lighting also features high quality electro-polished stainless steel covers designed to resist corrosion in even the most extreme saltwater environments.

The result? Style and durability. Most importantly, Attwood lights are built to stand the test of time. Rated for 50,000+ hours of use and protected by a 10-year warranty, you can count on Attwood products to light your way for years to come. LED Light Engine Consisting of an LED positioned and sealed inside a lens assembly, the “light engine” serves as the equivalent of an LED ‘light bulb”. It can be easily customized to meet the needs of the builder in terms of attachment scheme and overall dimensions.

Kevin

I have a Refrigerator that runs on 12 volt, 110 volt and LP Gas.

According to the manual, the 12 volt and 110 volt are two different elements but both require 125 watts.

I have a 1000 Watt inverter -12 volt to 110 volt - but in trying to run the 110 V on inverter it shuts off & on indicating a overload. How can that be if it’s only 125 Watt required ? The inverter works fine on other applications, e.g., 100 watt Bulbs.

I need help. What am I not seeing or knowing ?

John

John,

I doubt if you are overloading the inverter.

My first idea would be that your inverter is not capable of producing a pure sine wave output. Instead of being a sweeping curve like swells on the water, the wave form looks more like something you made on an “Etch a Sketch”. Or, the electronics in the refrigerator may be causing some form of feedback to cause the inverter to shut down.

Would it be possible to supply more info on the refrigerator and inverter?

Finally, I have not seen refrigerators that have separate 12v and 110v systems. Usually, the base refrigerator is 12/24v dc and has a rectifier that converts the 110v down to 24v dc. If this is the case on your unit, you would be converting 12v dc to 110v ac and then back to 12v dc.

Thanks,

Kevin

Kevin,

I am wondering if an electrical code exists for marine applications.

I have been told that the National Electrical Code does not apply to boats. Is there a similar code in place by which to judge the safety of AC power and wiring in a marine installation?

Would love to hear back on this!

Thanks,

Jerry

Jerry,

The boat wiring electrical standard that most OEMs try to build to is controlled by the American Boat and Yacht Council.

The main electrical standard is E-11. There are also several other separate standards that deal specifically with components such as battery chargers and galvanic isolators.

Thank you for writing.

Kevin

Kevin,

Firstly let me say thanks for taking my question. I just re-powered my 24 ft boat from twin outboards to a single 225 outboard (Johnson).

The boat now has two batteries and while I want to keep them both, I only want one for starting and I want to keep the other separate for electronics (it’s a dual type deep cycle/starting). I have a Perko brand battery switch I want to change to a basic “on/off” switch instead of having both batteries hooked to it.

I also seem to be having an issue with my Tach in that I don’t think it’s grounded properly and I think this caused my rectifier/regulator to short out two of the four bridge diodes (the ones to ground). So after this long winded explanation my two questions are as follows.

1. How do I rig the switch into a “on/off” switch
2. Once I’m on one battery with all negative leads going to the same battery (I have a negative buss bar), will this solve my ground issue with my rectifier/regulator so I don’t blow another one?

I’ve tested my others wires leading to my tach and I have continuity, so I’m thinking the ground has to be it.

Thanks again for letting me bend your ear.

Mike

Mike,

A great solution for your single engine boat wiring system is to use the BEP Dual Pole Battery Switch. This switch will allow you to turn both batteries off at the same time.

Another smart item to add would be a BEP VSR. This could be connected between the two load posts on your new battery switch. With the switch on and the engine running, the VSR will parallel the two batteries and charge both of them. With the switch on, if the system voltage gets too low, the VSR will open the circuit and protect the voltage in your cranking battery for starting. With the switch off, the connection is broken.

Always connect all grounds together in a 12v boat wiring system. Several different ground references are possible if they are not connected and could definitely be the cause of your rectifier failure.

Kevin

Hi Kevin,

I recently purchased an older runabout on which none of the switches seem to be working.

While there seem to be a few switch panels available for sale on the web, none appear to be anything that would fit on my dash. I checked with my local dealer about fixing the existing part, but he is quoting more for the job than I paid for the entire boat!

Can you give me any advice as to how I might be able to do this job myself? I have had a little experience with electrical work, but the “rat’s nest” that I’m finding behind this panel is fairly intimidating.

Thank you in advance for any help that you may be able to provide.

Switchless in Seattle

Dear Switchless,

Unfortunately, what you are describing is an all-too common situation with older boat wiring.

The problem often started with an old-line boat manufacturer who used inexpensive, highly corrosive wire while paying no attention to standard boat wiring practices - like using consistent boat wire colors for specific functions. The good news is that these sort of builders are usually (thankfully) no longer in business - the bad news is that someone, i.e. you, are now left to clean up their mess!

Compounding the problem, this already bad situation can often have been made worse by a series of boat owners either trying to fix the builder’s original mistakes or making sloppy boat wiring modifications of their own. Either way, the end result is often a boat wiring system where, at best, wires colors do not match and that does not work correctly - and, at worse, something catches on fire.

Up until recently, your only option was to rewire each circuit individually until all of your desired components worked. To do this properly, you would use the appropriate wire color for each individual component.

A more convenient solution might be a slick new system from EzAcDc that I saw for the first time just last week. What these guys have put together is a top-quality harness that can be used to completely rewire your existing switch panel.

The EzAcDc system appears to have all of the wires and circuit protection that you would need for your project. Once you are finished, you can connect the rewired panel to your current boat accessory harness or, if that is in as bad a shape as your panel, EzAcDc even offers complete boat wiring accessory harnesses that are terminated to be plug compatible to the repaired panel.

I hope that this is helpful.

Kevin

Hi Kevin,

I am adding a depth finder to my 2007 Crestliner boat and have an Accessory switch that is not being used.

Do I wire the red wire directly to the toggle switch or to the accessory circuit breaker? Also where is the black wire attached?

Thanks for your help!

Tim

Tim,

Before you connect the depth finder to the accessory breaker, check your depth finder owner’s manual for their recommendation on circuit protection.

Most boat builders have 10 amp breakers on their accessory switches. You may need to add an in-line fuse for this boat wiring project if the supplied Accessory breaker is not the correct size for your depth finder.

As for the wires, if you want the toggle switch to turn the depth finder on/off, then you can certainly wire it to the switched side of the toggle. Personally, I like to use the power switches that are provided on the electronics and not a separate switch.

The black wire should be attached to a ground buss at your helm. It is common for boat builders to not provide additional grounds for boat owner add-ons. Although it is not the best place to ground your depth finder, you can connect it to the chain of grounds from your existing gauges or your switch lights.

Thank you for writing.

Kevin

Hi Kevin,

Many thanks for making this service available - reading the previous posts has been a real eye-opener.

I have what I think is a silly question, however I’d like to check:

I have two batteries, both lead-acid sealed 12 volt.  One is a 70 amp/hour, which wasn’t up to the job of providing enough current to turn the engine over in the mornings after sleeping over on the yacht. So, I went out and bought a 110 amp/hour which is.

I’d like to use both of these batteries - with the large capacity to run the boat systems and the smaller as a reserve / starter battery. The wiring to a main switch that allows Battery1/Battery2/neither /both is in place.

I think that I can simply connect the two batteries despite their different capacities, so that when ‘both’ is selected they will discharge together and/or charge together.

I believe that if one has a higher voltage than the other at the point of selecting ‘both’ then the higher will discharge to the lower until they are equal. I don’t believe that the fact they both have different maximum capacities will affect their use.

Am I right?  Is there any drawback to connecting two batteries of different capacities?

Thanks!

Evan

Evan,

You are correct. You can certainly connect two batteries with different reserve capacities in parallel with your battery switch.

You may want to consider modifying your boat wiring system by adding an emergency paralleling VSR like the one from BEP Marine instead of the battery switch.

This switch will automatically parallel the batteries when the engine alternator is charging the system. When the system is not charging and the voltage is below 12.6 volts, the circuit will open up. This device also offers an emergency paralleling feature that can be manually operated or remotely from a button.

Thank you for writing.

Kevin

Kevin,

I just purchased a boat with a fairly complex electrical system, which was disconnected.

I am trying to piece it back together again with an incomplete wiring diagram. Some components have been added, removed or changed since the original diagram. In addition not of the components provides documentation for this full scale system.

The system is comprised of

• One engine battery (actually 2 6v serial),
• One house battery (also 2 6v serial),
• Solar Panel with Solar Regulator, Alternator,
• Battery Isolator,
• Heart Inverter/Charger
• Dockside AC.

I would love to see a sample wiring diagram for this type of system if one exists anywhere. If not, my biggest question is where to ground the AC? I have read conflicting information regarding whether the AC & DC should be grounded to the same common ground.

Can you shed any light on the subject and/or direct me to resources that might be helpful?

Dazed & confused,

Andi

August 19, 2008

Andi,

I have never found a great resource for boat wiring diagrams. It usually comes be piecing together schematics from several sites.

One of my goals for Easy Ac/Dc is that perhaps someday this site will become a no charge repository/library for this type of boat wiring information, which would be a real aid to all of us who work with marine electrical.

So, if any of the readers know of a source for diagrams and schematics - or, if you would be willing to contribute a few of your own - please send me an email. If everyone contributes just a little, the amount of material available to all of us should be impressive.

On a more helpful note, please check out the Guest battery isolator manual. This should help you to correctly connect your battery isolator.

AC Ground

• All AC ground green wires are connected at your AC distribution panel.
• The AC ground and AC neutral are not connected.
• The AC ground should be connected to the DC ground.

The main reason for this arrangement is to trip an AC breaker if there is a fault between the AC and DC systems on your boat. Without this connection, when a fault occurs, all metal components connected to the DC system will become energized at 120v ac. There is too much resistance in the water and no direct path back to AC ground to cause the breaker to trip.

I hope that this is helpful.

Kevin