Pearson Yachts Forum
Pearson Boats - Common Systems => Plumbing and Galley Systems => Topic started by: T_schlueter on December 02, 2019, 09:14:14 PM
-
I'm replacing my raw water thru-hull and noticed the old one wasn't bonded. The ground wire terminates nearby. I suppose I need to run a short wire to my new thru-hull. Sound right?
-
Yes, you got it.
Since this is in a damp bilge location, be sure to use tinned wire, and waterproof the connections using adhesive-lined heat-shrink tubing.
-
It would seem a previous owner replaced the thru-hull without attaching a short jumper wire. Is it typical to terminate short thus requiring a jumper? I've attached a picture.
-
I just ran across a West Marine article written in 1996 by electrical engineer Stan Honey. According to him the "bond everything" traditional approach is counterproductive other than in open sea environments. Here is an excerpt pertinent to this topic: "An isolated bronze thru-hull doesn't need protection because it is not in electrical contact with another immersed dissimilar metal. If electrically isolated, high quality marine bronze, is electrochemically stable in seawater; nothing good can come from connecting wires to it."
-
This is a complex topic, and there are many differing and contradictory points of view.
Stan Honey's position is perfectly correct ... if all you're concerned about is galvanic corrosion. Unfortunately, there are other factors to consider, each of which interact with the boat's grounding/bonding system. Not all apply to every boat. Some of these factors are:
- Galvanic Corrosion
- Lightning Protection (Controversial in itself!)
- Performance of Radio System's "Ground Plane" (VHF, Radar, AIS)
- Shore Power Safety Ground
- Presence or absence of a Galvanic Isolator
- Presence or absence of a Ground Fault Interrupter (GFI)
You can find "experts" that argue for everything from "Bond Everything" to "Bond Nothing"!
You should try to learn as much as possible, and then make a decision based on your specific situation.
-
I don't know what to do for now. Does the P323 come equipped with a galvanic isolator?
-
No, it does not. This was the very first project I did after purchasing our 323, and one I strongly recommend if you have and use a shore power connection.
Here's a link to my project page:
http://www.chessie.com/boat/projects.shtml#GalvanicIsolator
-
Thx! I like your portlight project as well. All mine leak.