Kevin,

I have a 1978 30′ Tollycraft boat. It has twin engines and a closed cooling system that takes in raw water via thru hull fittings which is then pulled through the closed cooling system via raw water pumps.

The boat is berthed in a marina and is connected to 120 volt shore power when berthed. It has four batteries, that are charged via engine alternators or a 120 volt battery charger. It does not have a generator. When needed, I use a portable Honda generator. It has standard electronics (GPS, fish/depth finder, VHF radio), a 120 volt refrigerator and a 120 volt water heater,

I noticed the original bond wire from the pumps and other parts of the drive train have broken off or were not connected properly.

I’ve heard some mention to run a heavy copper pipe the full length of the boat and what ever needs to be bonded is connected to the pipe which eventually is connected to the bonding plate, or that wire and bus bars are used. What items need to be bonded, and what is required to bond these items correctly?

I presume all bonded items make their final destination to the bonding plate located at the transom. Is that correct?

Please let me know.

Thanks,

Chuck

Chuck,

It is no surprise that your original bonding wires are starting to rot/corrode off. They were probably made from straight copper wire as compared to tinned boat wiring.

You certainly can run a copper pipe through the hull of your boat as a common bonding point, but it is very difficult to install when the boat is completely built. You will also increase the number of connection points in your bonding system that are difficult to get to and inspect.

My preference is a common bonding bar with individual (in most cases) bonding wires running to every underwater, metal device. This is connected to the engine negative (or its bus) and also to your bonding plate.

Wires fail at connection points. A common connection point is much easier to inspect.

Hope this helps,

Kevin

Hi Kevin,

Thanks for getting back to me.

Yes, that is correct they used a straight single copper wire for the bonding, versus tinned stranded marine wire. They ran the bond wire from the bonding plate to each item, drive shaft packing flange, engine, transmission, and raw water intake valve and filter assembly. No common bonding bar where each device is connected to and the bond bar is connected to the bonding plate.

So now that you know what type of flawed system I have. My original questions still exist.

1. What needs bonding?
2. What needs grounding not bonding or vise versa?
3. What type of common bus bar should I use (what do you have to sell)?
4. How are the bonded items connected to the common bus bar (stranded tinned wire with a gauge of? and connected by means of ?)? Standard rules of thumb for wire gauge and type?
5.  How is the common bus bar connected to the bonding plate (stranded tinned wire with a gauge of? and connected by means of ?)?
6. Should I use any type of protectant on the wires and connectors (dielectric grease, anti oxidant grease, etc.)?

Please let me know.

Chuck

Hi Chuck,

Here is a copy of the ABYC marine electrical standard that explains how to install the system and what items to bond.

Hope this helps,

Kevin

Hi Kevin,

Thanks for the standards.

I looked over the section on bonding and grounding. I’m still confused of where the final ground destination is. The information stated the negative terminal of the battery goes to the engine ground, however the schematics show the engine goes to a ground. Where is the engine grounded to, the bonding plate/anode located at the transom or other? Please clarify

I’ve also seen a lot of conflicting information on what type of wire goes from the bus bar to the end ground source. Many articles say #8 primary stranded tinned wire can be used but the run should not exceed 2′ in length. If that is so, how do you go from the bus bar back to the final ground destination, battery or bonding plate, which would be a lot more than 2′ in length?

Please clarify.

Thanks,
Chuck

Hi Kevin,

I have a 1978 30′ Tollycraft sedan. My question is in regards to bonding.

My boat has a fiberglass hull, twin gas motors, two stainless steel fuel tanks, twin direct shaft drive, twin rudders, battery charger, isolator, four batteries with two boat battery switches, electronics (VHF, GPS, Fish/Depthfinder), 120 volt fridge, 120 volt water heater, 12 volt lighting.

When working on the boat, I noticed a lot of the marine wiring that appears to be old bonding wires is old and has either bad connections or has completely broken away from the parts it was connected to.

The boat was recently hauled out and new zincs and a new grounding plate were installed. What is the best method for bonding (wire size, methods for attaching, one main bond wire that others are connected to, or each individually bonded, etc.)?

I’ve seen various articles on bonding but remain not completely clear on the correct way to bond the boat and make sure all grounding has been done correctly.

Please explain.

Thanks,

Chuck

Hi Craig,

Here are the current ABYC standards for marine electrical systems. Please check out Page 31 and 32 which spell out how to bond your system.

Once you’ve checked the specs, please let me if you have any other questions.

Kevin

Hello Kevin,

I currently have a 1991 26’ Macgregor Sailboat that is in need of shore power and while looking online I came across your partner marine wiring site.

The boat has a basic one battery DC setup to power its navigation lights, Radio, and interior cabin light but has no way of charging the battery since it’s primarily a “trailer sailor”.

I recently purchased a new Honda four-stroke outboard which has a charging feature that I have not connected since I mainly trailer the boat and charge the battery with a portable charger when I come home.

However, I’m in the process of moving the boat to a local marina with standard 30A service (west coast CA) and would like to add a permanent Guest style charger/maintainer, GFCI convenience outlets for a TV, laptop, portable heater, etc. and would like to see what options are available.

Also, if I were to go with one of your complete marine electrical shore power systems, how would I connect my outboard’s charging system to the battery without interfering with the AC connected battery charger? Can they both be connected at the same time or would I need some sort of switch (I wouldn’t run the two systems simultaneously).

Could I run the DC powered cabin light, radio etc. while the shore power is connected and charging the 12 volt system as well as any accessory connected to the convenience outlets?

I’ve also read about galvanic corrosion… would this be an issue since I don’t have any thru-hulls and raise my outboard when docked? As this is my first boat, any help with selecting the correct components and with getting wiring schematics would be greatly appreciated!!

Thanks

Ernie

Hi Ernie,

Our EzAcDc shore power system will easily accommodate any Guest style charger/maintainer, which could simply plug in to one of the outlets on the back of the panel assembly. Along with protecting itself, the front panel GFCI protects all remote outlets. Additional GFCIs are not required.

Your boat battery cables, existing boat DC system, and battery charger can all be connected to the battery at the same time. There is no need for a marine battery switch. Even though it will probably never happen, the battery charger can be on while you have Honda running and charging the battery. They are designed to be able to work together.

While you are plugged into AC, you can certainly run your DC equipment along with your AC TV, heater, etc. As long as your battery charger is large enough, it will be able to keep up with the additional DC loads. If you plan on running your DC equipment for extended periods of time while your battery charger is on, you may want to consider buying a charger that is large enough to charge the battery and run your DC equipment.

As long as you do not have any metal hull fittings, galvanic corrosion should not be a problem on your boat. Even though the GFCI will protect against most AC fault issues, please make sure your AC and DC grounds are connected together. Our AC shore power panel provides this ground wire.

Hope this helps,

Kevin