Mast Grounding Wire

[MFC]

Can someone tell me where the mast grounding (or bonding) wire should terminate? One end runs to the grounding plate, the other end comes up the mast track through the interior of the boat and then ????
TIA
Matt

[Dalton]

Ours is connected to the mast step.

GD

[Jim Cornwell]

Bonding wire is bolted to mast step on Yankee. Some of those bonding wires disappear into the gloom under the sole and their condition is unknown, so when hauled for the winter and grounding plate is readily accessible, a planned project is to test continuity of all bonded items to the grounding plate. I wonder if I'll get around to actually doing this?

[MFC]

So, when you guys say it's connected to the mast step, do you mean that it doesn't run up the mast track? That's interesting. Mine is connected from the mast step to the ground plate but then runs up the mast track to the coach roof level and is now loose or broken near that point.

[Jim Cornwell]

On Yankee, bonding wire terminates at mast step, meaning that the mast extrusion itself is the conductor from the masthead. There could be oxidation at the step, causing an imperfect electrical connection, I suppose, so a copper bug between the bonding wire terminal and the mast extrusion would be an improvement. Perhaps you once had a lighting rod aloft with an independent conductor....

[MFC]

Perhaps you once had a lighting rod aloft with an independent conductor....

Yeah, that was called my VHF antenna! Its kinda hard to figure out what the grounding wire did before since the charge clearly followed the wire and may have burnt through it at some point. In any event, it is interesting to know that most boats don't seem to have the vertical wire that I do and that it apparently "worked". Thanks again, I'll see if I can post a pic of (what's left) of it.

Matt

[MFC]

Here's the "bonding" wire and the scorching:

[img]http://lh4.ggpht.com/_2Lg5unxPjB8/Sn5Ou ... %20002.JPG[/img]
[/img]

[Oswego John]

It is hard for me to make out, but is the conductor shown in the picture solid or stranded?

For bonding and grounding purposes, it is recommended to use stranded wire.

Try to use the same metal throughout the grid system. Copper cable is recommended and seems to stand up better in the long run than aluminum. Whichever metal you choose, make sure that you use Al-Cu (aluminum and copper) type fittings, lugs and other terminations.

If you use a jumper wire from the ground in the cabin to the mast base, as well as in any other areas, smear on all contact points a coating of some type of antioxidant such as Noalox or Penetrox. It is best to lightly brush the antiox cream down into the crevices of the stranded wire for total protection. This will help prevent corrosion between contact points.

Good luck,
O J

[Jim Cornwell]

My bonding wire is a heavy gauge solid copper. Isn't that standard on CDs? Cable used for building lightning protection systems is woven copper, which could be considered a variation on stranded, I guess. But each individual strand in the weave is still a substantial gauge. It strikes me that solid bonding wire has a longer life expectancy in damp bilges than stranded wire would have. All of my bonding wires have suffered some oxidation, evidenced by powdery green oxide, that would have long since destroyed a stranded cable, I think. Is there a way to arrest this?

[MFC]

It is hard for me to make out, but is the conductor shown in the picture solid or stranded?

For bonding and grounding purposes, it is recommended to use stranded wire.

Good luck,
O J

The existing bonding wire is the solid 8awg shown. I understand that today's standards call for #4 instead.

I am wrestling with whether or not to remove all of the existing bonding wire and to replace it.

Galvanic survey revealed less than adequate readings at a couple of the forward thru-hulls which also appeared visually hot (bubbling paint). That said, the bonding wire appears to be in place everywhere except a termination point along the upper end of the mast extrusion (the other end of the wire shown loops the lug on the mast base and proceeds to the grounding plate).

The electrical work in general is new to me and the bonding process in particular (exactly what those galvanic survey results mean and how propoer bonding would change them) is tough for me to grasp.

Right now, I am just trying to assess the amount of work involved . . . while I read the 12 Volt Bible and other primers on marine electric.

Thanks!

Matt

[jbenagh]

After a sail with a friend who is a specialist in protecting electronics from lightning, I learned a few things.

Other things being equal, stranded wire is better than solid wire for lightning protection. The higher frequency currents of a lightning strike travel mostly on the surface of a conductor. A stranded wire has more surface area than solid, thus the flat cables of house or telephone pole electronics grounding (like cable or phone equipment boxes).

Given the harsh moisture environment on a boat, I think it's a wash whether you use solid or stranded. Either way, you need to inspect for corrosion, maintain and replace degraded grounding wires. Stranded is a lot easier to work with.

What I read was #4 for the mast since it is so conductive, and #8 to all the shrouds and stays since they are less conductive. The smaller sized Dynaplate is adequate for all lightning protection. Be sure you bond with #4 to the zinc. And remember there's no guarantee: ABYC says "protection" means 90% likely to survive a strike with only minor damage -- so avoid lightning if you can.

Jeff

PS some references for the technically-minded:
http://www.arrl.org/tis/info/lightning.html
http://www.polyphaser.com/technical_notes.aspx