Boaters Guide to AC Electrical
Many seasoned boaters have an aversion to using AC Electrical around boats in marinas.
Water. Electricity. That’s a natural concern.
Marinco has been designing, building and supplying the best marine AC electrical products since 1972. Safety is always the first concern. And the best way to ensure safe shore power product usage is through training and education.
Marinco makes it easy to know how to use these products. They publish a great booklet entitled: “Boaters Guide to AC Electrical”, known around the marketplace as the “Shore Power Manual”. It’s the definitive resource when it comes to shore power. This guide drills out the mystery and concern, with straight-forward, easy-to-understand tips on AC Electrical.
You can order this booklet by visiting their website: http://www.marinco.com/view/96/guides
Editor’s Note: John Tinghitella formerly VP Sales / Marketing for the Marinco Electrical Group spent many years in the trenches of the marine electrical products market. He’s moved on and now runs the hottest negotiation training group in the business.
Contour Zone: The Next Great Leap in Boat Electrical Technology
BEP Marine and the Marinco Electrical Group have invested heavily in a new digital switching platform that’s sure to revolutionize marine electrical functionality.
BEP Contour Zone is a state-of-the-art, networked power control and monitoring system designed to intelligently integrate and simplify onboard electrical and mechanical systems for greater functionality and an improved boating experience. The intuitive Display Interface enables control of DC loads, tank levels, and a host of other functional features
Compared to traditional marine electrical layouts, CZone decentralizes the DC power distribution system and locates circuit control and protection modules closer to loads to shorten cable runs and reduce the size of conductors, thereby decreasing the cost and weight of the boat wiring harness. CZone replaces complex inter-helm boat wiring with a single data wire.
Highly customizable, CZone is the only system that is cost-effectively scalable on boats ranging from 15 to 90 feet. Modules can easily be added to best suit the OEM’s and end user’s needs. The Plug and Play system is designed for simple, fast installation requiring no factory set-up. If a module is damaged, the system will automatically program the replacement module when it is plugged in, removing the need for an on-site professional technician
Editor’s Note: John Tinghitella formerly VP Sales / Marketing for the Marinco Electrical Group spent many years in the trenches of the marine electrical products market. He’s moved on and now runs the hottest negotiation training group in the business.
Best of both worlds — Guest Chargers + BEP VSR
The Guest range of Charge Pro Plus chargers combine reliable Guest charging with state of the art BEP voltage sensing. The benefit for the boater is simple…you can charge your batteries while on the water (DC to DC) as well as the normal AC route. The BEP VSR module is integrated into the marine electrical system and simply sends alternator current to where it’s needed most while you’re underway. Sort of like a charging traffic cop deciding where to send the juice. And it’s seemless to the user. You get to do what you should do…fish, boat and have fun.
Editor’s Note: John Tinghitella formerly VP Sales / Marketing for the Marinco Electrical Group spent many years in the trenches of the marine electrical products market. He’s moved on and now runs the hottest negotiation training group in the business.
Possible to salvage old switch panel?
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
Boat wiring diagram available?
Dear Kevin,
I just purchased a 1990 Thunder Craft bow rider. As far as I knew everything worked on the boat when I picked it up at my friend’s house – and he had shown me that all systems worked.
I took the boat out to local lake and submitted to a voluntary safety check. The boat passed with the
exception the navigation lights. They had worked before. I had cleaned and lubed all electric connections on the battery and the stern light with dielectric grease.
I guess that my question is do you know of a location of a boat wiring diagram with component locations for a 1990 Thunder Craft 1560 SE? Or, is there a fuse box in the boat that I just can’t find?
I have searched the web to try and find something I can use and the only thing I can find is info on a legal case against Thunder Craft from another company. I know the boat company isn’t around anymore because I can’t find anything on them.
Can you help?
Thank You,
Robert Thompson
Robert,
Boat wiring diagrams are rare for new boats and almost non-existent for older ones. Your best bet is trace each individual wire. This may be easier with a boat wiring color chart like the one that we have posted on Easy Ac/Dc.
If the boat was built to USCG standards, then there should be a fuse block or breaker panel near your helm switches. 
It is very possible that a previous owner did some creative wiring and removed some components.
If you absolutely don’t have a fuse block or breaker panel, you really need to add circuit protection for the individual circuits.
As for the navigation lights, since they have quit and all the wiring is intact, it is very possible that the nav/anc switch is malfunctioning. In the early 90s, builders used unsealed, inexpensive switches that were prone to corrosion. Most of these switches can be dis-assembled and cleaned up. Most can then be reassembled. But, some cannot!
Is the remaining wiring in decent shape or does it make sense to do some rewiring?
Let me know. I have some ideas.
Kevin
1974 Sea Ray boat wiring issue
Here is a boat wiring inquiry from a Easy Ac/Dc reader with a 1974 Sea Ray.
Kevin,
I have recently purchased a 1974 Sea Ray boat, it is 22′-9″ long, inboard/outboard with a rebuilt Ford 351 engine.
The engine has not been wired to the ignition. I cannot get fire from the coil, although the engine turns over and I have power from the ignition “purple” wire to the positive side of the coil. The boat has points and a coil with an internal resistor. I cannot even get spark form the coil to the block never mind the plug wires at this point.
There are two wires from the boat wiring harness that are purple (one purple and one purple with a white stripe), I have tried it with them both hooked up and just the purple. I do not see a neutral safety switch wire from the boat harness. I currently do not have any of the gauges/trim hooked up.
I am at a loss, any help would be greatly appreciated!
Sincerely,
Roger – New boat owner
Roger,
Usually the purple is the ignition wire and the purple/white is the trim position wire.
- First I would eliminate the entire boat wiring from the system. Something as simple as a shorted out tach lead will cause your problem.
- Eliminate any ignition interrupters. I/Os in the 1970s had all these complex ignition interrupters to help stall the engine when it was shifted into gear. They usually were hooked to the negative side of the coil.
- Remove all extra wires from the coil. They are not necessary for starting.
Here is all the you need:
- 12 volts to the plus side of the coil
- Negative side of coil to points
Finally, as far as the safety stop switches are concerned:
Neutral safety switches usually break the yellow/red start wire. Emergency shut off switches usually break the ignition circuit. They are wired 2 ways:
- Type A – Ignition wire is broken before ignition switch – this makes all gauges and dash functions quit and it is obvious that the ESS has been pulled. They engine will no longer turn over.
- Type B – Ignition wire is broken after the ignition switch – this is easier to wire but is not as obvious when it is tripped. Gauges work and the engine will still turn over.
Hope this helps,
Kevin
Ground leads and polarity on battery charger installation
Steve wrote to us with a couple of installation questions about his battery charger.
Kevin,
I just bought a Guest Cruising Series 30 amp charger and the wiring diagram calls for individual ground wires routed to each battery bank.
My old charger had 3 positive leads to the battery banks and a single negative lead. The ground wires used jumpers between 1,2, and 3 banks so only one exit ground lead was necessary. This is how I would like to set up my new charger since all of that boat wiring is currently in place.
All of my battery banks are currently grounded together, but isolated by positive Will this work?
Steve
Steve,
You can certainly tie the 3 ground wires together since your system has a common battery ground. The new charger that you purchased actually has 3 separate chargers inside and is designed to work on a 12 volt, 24 volt, or 36 volt system.
Rather that trying to explain all the different combinations of connecting the charger, the manual says connect the charger directly to the battery.
Please make sure that your common ground wire is large enough to handle the entire 30 amps that the charger is capable of supplying.
Thanks,
Kevin
Kevin,
One more question…
I just installed my unit and I do not have access to the boat until next week. I realize now that I connected the AC connections backwards. The white wire is connected to “LINE” and the black wire is connected to “NEUTRAL” I also understand that AC is alternating, so it may make no difference.
Will I damage the unit with it hooked up like this? It worked fine when hooked up and didn’t notice that I did it wrong until I got home and looked at the manual.
Steve
Steve,
Connecting the AC wires backwards is common. It doesn’t really matter on the potted Guest battery charger. However, following the standard practice of Black is Line and white is Neutral will make it easier for anybody in the future to work on your boat.
Problems can occur on appliances that have their neutral (white) connected to their case ground (green). If they are wired backwards, the black wire in the outlet will be connected to the white wire on the appliance. If the white wire is connected to the case, then the circuit is completed through the green(ground) wire and the circuit breaker/fuse will hopefully trip.
Thanks,
Kevin
Troubleshooting a Mercury breaker overload
This came in from one of our readers last week:
Hi Kevin:
I am having an electrical problem with my 2006 Mercruiser 4.3L TKS 190HP I/O. The problem is that the 50 amp circuit breaker for the Overload Electrical System keeps popping every time the engine is put into med-high RPMs.
I have tested the battery, checked all wires, wiring harness, etc., all everything looks normal.
Any idea what might be causing this breaker to pop or where can I begin troubleshooting?
Thanks, Andy
Andy,
In 2006, Merc made a major change as to how their electrical system connects to the boat’s wiring harness. Instead of running the entire boat’s electrical supply through the engine harness, boat builders were supposed to run a secondary power harness supply all non-engine related functions.
At mid-high RPMs, the alternator is putting out it’s max current and max voltage. Something very simple is pushing the system beyond the 50 amp max.
Voltage = current x resistance. The resistance of the items on your boat do not change. As the voltage goes up, the current will go up.
It is possible that the power trim pump is causing the breaker to pop. Under load, the pump has the ability to draw 75 amps. If this is connected to the starter end of the red battery cable, it is possible to have the alternator try to supply the entire 75 amp demand and pop the breaker.
Troubleshooting:
- Begin disconnecting items that are powered through the ignition/engine to stop the breaker popping. This could be as easy as removing fuses.
- Disconnect the power trim pump if it is wired directly to the starter.
- Add an additional power supply wire to the helm area. Install an ignition protected breaker or ATC fuse within 7” of where it connects to the battery.
- Connect the power trim pump power leads and ground to the battery.
Let me know if this helps or if you have any other questions.
Clever “QuickConnect” for DIY Pontoon Electrical
Several of our readers have alerted us to a very slick offering from the folks at Pontoonstuff.com. Their new QuickConnect line goes a long ways towards alleviating the confusion (and headaches) caused by adding major electrical components to – or totally rewiring – an older pontoon
boat.
Pre-loaded and pre-wired to make installation exceptionally easy, the Pontoonstuff QuickConnect system includes OEM quality gauge panels, switch panels, accessory harnesses, and even a deck-mounted light holder complete with sidelights, horn, and docking lights. And, as the name suggests, all of these parts are engineered to be quickly connected together by the boat owner.
It is obvious that a lot of thought went into this system, which is built from the highest quality marine grade materials. Everything is strictly first-class, from Carling switches and Faria gauges on the panels to the Attwood and AFI components in the light pod. All of these parts are then wired with the finest quality copper wire – tinned for superior corrosion-resistance. As you would expect, both the wiring and the circuit protection accurately anticipate the usual amp draw for each accessory.
This QuickConnect family of products assures that DIY electrical work can be done both quickly and safely – at least for pontoons. One wonders why a similar system couldn’t be offered for other types of boats?
Circuit Protection – Where does it go?
Any boat built to NMMA (National Marine Manufacturer’s Association) standards has circuit protection for its boat wiring system. These breakers/fuses are specified to provide adequate amperage for all standard equipment. And, the original boat wiring is sized for the factory installed system.
Problems occur when the boat owner or dealer begins to add other items.
The best and safest position to place your circuit protection is as close as possible to the source of power (battery or distribution panel). For example, a new fish finder is added to the helm of a boat. There isn’t an obvious way to splice in the existing boat wiring to connect the power and ground wires. The solution is to run a new pair of wires to the battery. The fuse for the fish finder needs to go as close as possible to the battery. The fuse is protecting the fish finder and its wiring. If the fish finder has an internal fault, the fuse will blow. If the wire between the fish finder and the battery gets damaged, the fuse will blow.
If the fuse is installed close to the fish finder, then in the case where the wire is damaged between the fish finder, the wire will burn instead.
Circuit protection is also very important when adding additional charging sources. This new charging source is considered to be a source of power that needs circuit protection. If it is not a “self limiting” device, circuit protection is needed at both ends of its positive output wire. Most chargers are self limiting.
For example, let’s say that a solar battery charger is added to boat. It has 4’ long leads with an inline fuse 7” from the end of the positive lead. The boat owner needs to add 8’ of wire to allow the charger to be connected directly to the battery. As long as the wire doesn’t get damaged, this setup will work fine.
Problems occur when the wire gets damaged. If the wire is damaged between the charger and the inline fuse, the self limiting battery charger will shut down, and the blown fuse will limit the output of the battery. If the wire is damaged between the inline fuse and the battery, the battery will continue to discharge until it is depleted or the shorted wire has completed burned up. This usually results in a fire.
