Bonding/Ground Connection on flybridge?

[Streff]

I am installing a new Autopilot control system. I need to ground it to avoid electrolysis, etc. I identified a bonding lash on the Starboard side under the FB helm next to the decommissioned SSB box. To my surprise, the other end of the bonding belt goes down a chase tube toward the space behind the Pilothouse seat and it’s dangling free in space, not connected to anything at all. And there is nothing around where it logically can be connected to another ground lead.
There are a bunch of electronics equipment under the helm dash, I assumed that I can find where do they all ground. After a day of looking everywhere, I cannot locate a green ground connection on the FB, other than the lash to nowhere.

Any comments or ideas as to where I may find a ground on the FB would be much appreciated.

Streff

 

[Streff]

I ended up running an 8AWG bonding wire from the port ER up to the FB. That solved it for my install.

 

[Bob Bradley]

I'd be surprised if your DC panel on the bridge didn't have a one. Both my '79 43C and my '86 45C have it. They also both have glassed in post in the forward area under the FB windshield. I found mine by rolling over on one while installing a new horn - didn't do my ribs any good at all. I'm not familiar with your 53 though.

 

[CGHOST4]

A note of caution. Bonding and grounding are two different things. My thru hulls are bonded together, my electronics are grounded to the battery. Using the bonding system as a ground for your electronics could result in stray current eroiding your thru hull fittings. There is a lot of information on the internet about this subject. I hope this helps.

Caesars Ghost
1980 58YF #472

 

[Streff]

Thank you very much for the input. I called Simrad to confirm what they mean by grounding to the vessel grounding system and they said it’s the shield connection.. whatever that means. I don't think they really know. I will call again on Monday and ask to speak to a level 2 support.

Streff

 

[Avenger]

A shield is usually either a foil, or woven wire material surrounding the conductors of a cable.

 

[drewread]

Thank you very much for the input. I called Simrad to confirm what they mean by grounding to the vessel grounding system and they said it’s the shield connection.. whatever that means. I don't think they really know. I will call again on Monday and ask to speak to a level 2 support.

Streff

You can attach the ground wire and shield (drain) wire both to the vessels negative DC buss.

This is from the current Raymarine Axiom installation manual, but it is the same idea.

If you don't have a RF ground readily available, use the negative buss. I have used it successfully a few times.

 

[Streff]

Thank you very much for that, Drew. That’s very helpful. I do have a couple of attachment points under the FB helm with old labels/tags indicating RF Ground. I thought these are/were primarily aimed at grounding VHF or SSB antennas/units from the 80s. One attachment is right next to an old decommissioned SSB box from back when.
I dismissed them as an option to ground DC units. Different functions but I could be wrong. I also could have been incorrect in connecting the Shield/ground to the bonding network in the ER.
I am using a standalone 12V battery (with its own charger) placed under the helm to power the new Autopilot (30A), the N2K backbone and AP head/MFD as all my 32 to 12V converters are spoken for. So maybe connect The Shield to the engine block or possibly to the source battery as an option.
From my reading, it seems that the engine block connects to the main battery neg and to the bonding system. Still much to learn.

 

[Boatsb]

This is all the very basics of installation. The "drain" or chasis ground is not a new concept. Both the bonding and DC ground are common. Major differences are required wire sizes and method of attachment. If its not something you understand you should be messing with it.

People wonder why professional installation isn't cheap. Then owners question the manufacturers support peoples competence because you don't know the basics. That's like doubting your cardiologist because you have chest pain but don't want to pay the co pay so you look it up on the internet.

 

[drewread]

Thank you very much for that, Drew. That’s very helpful. I do have a couple of attachment points under the FB helm with old labels/tags indicating RF Ground. I thought these are/were primarily aimed at grounding VHF or SSB antennas/units from the 80s. One attachment is right next to an old decommissioned SSB box from back when.
I dismissed them as an option to ground DC units. Different functions but I could be wrong. I also could have been incorrect in connecting the Shield/ground to the bonding network in the ER.
I am using a standalone 12V battery (with its own charger) placed under the helm to power the new Autopilot (30A), the N2K backbone and AP head/MFD as all my 32 to 12V converters are spoken for. So maybe connect The Shield to the engine block or possibly to the source battery as an option.
From my reading, it seems that the engine block connects to the main battery neg and to the bonding system. Still much to learn.

I believe your 12V battery negative DC terminal should be tied into the main systems negative DC grounding system. This would bond all of the negative Vdc systems together.

If you have a NMEA2000 network or Ethernet network connecting this equipment together you don't want to rely on the small gauge wires on those networks to carry any stray current or transient voltage from system to system. Much better to rely on a bonded negative Vdc system.