Bonding Rules

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.Tollycraft 30

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.



Hi Craig,

Here is a site with the ABYC standards for marine wiring 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.