Grounding

whatfiero · Jul 3, 2012

attach to negative battery terminal that is ground

CaptGregg · Jul 3, 2012

I have a grounding bar close to my 12V DC fuse panel where all circuits are grounded to and that in turn is grounded to the negative battery terminal. I've asked in the past about bonding to metal objects in the vessel and was offered by someone on the board that it was not needed, the grounding bar to the battery is sufficient.

My old grounding bus looked like just square metal tubing with holes drilled in it. Check out my profile, I think I have an album in there with pics showing my old aluminum ground bus verses my new "store bought" fancy smancy ground bus.

Being as I was an electrician for 4 years on land (mostly AC systems, none of which had marine applications) doing it right is a big deal for me.

CaptGregg · Jul 3, 2012

It's in my album titled "Albermarle Sound Sailing June 17, 2012"

allen-deckard · Jul 3, 2012

Don't want to complicate things although i probably will anyway

But negative and ground are not necessary the same thing in a 12 volt marine system.

Neg is your neg terminal on the battery or any wire obviously that is in that circuit.

Ground is basically something leading to the water.

In a house system they are for all intensive purposes the same thing.

Im not sure what your reading but if for example its your transition antenna on your radio it needs to be grounded for lightening not for your electric return path.

Anyway sorry ignore me if need to i was electronic warfare systems spec. In the military then industrial electrician for many years between worked at advance mixers building cement trucks i did the wiring and for a hobby before getting into sailboat used to restore cars. Im not bragging its labor work nothing to brag about re reading it it sounds lm passing myself off as some guru.

Honestly the wiring in my boat is pathetic (i didn't do it) and its on my list of things to do this winter.

Stu Jackson · Jul 3, 2012

Ground on a small boat was correctly answered in reply #2. These boats usually have outboard engines. Larger boats with inboard engines, the battery negatives are "collected" into one negative wire to the engine (which is) ground. Bonding of underwater metal objects and other more esoteric issues like lightning, is discussed here, but usually doesn't apply to small boats: http://www.westmarine.com/webapp/wc...catalogId=10001&page=Marine-Grounding-Systems

CaptGregg · Jul 3, 2012

Milton, you have received a plethora of information here, as I stated in my earlier post, what I was going on was what I was told and I could use more explanation from anyone who will offer. Allen and Stu both have given me great advice in the past so Allen-deckard? BORE AWAY MAN!

As I previously stated in my post, I have my negative terminal from the battery attached to the terminal block and all black wires from DC equipment terminating to that block. Is this correct?

allen-deckard, you stated that grounding the antenna for lightening strike protection should be to metal that touches water correct? I do not (at this time) have an outboard and don't think I am going to get an outboard with an alternator so should the bonding for the new VHF antenna I will buy need to be grounded at the keel winch since the keel winch and cable runs down into the water attached to the retractable keel?

I saw on ebay a VHF antenna that states it does not need to be grounded, should I stay away from an antenna such as that?

CaptGregg · Jul 3, 2012

Oh yeah! One other question that's pertinent, West Marine advisor states that the bonding to sea water should be at one place only. When I connect my AC panel to my shore power connector and my outlets in the boat, should that bonding to seawater be done in such a way to bond my DC system too?

anchorclanker · Jul 3, 2012

Ground (as opposed to the +/- pos and neg power wires) would only matter if you had a metal chassis, or in the case of a sailboat, if your rigging were bonded and grounded.

However, even if your rigging is not grounded/bonded, if your antenna is attached to the metal mast in such a way as there is any actual metal to metal contact, then the ground wire from the radio should likely be bonded in some way to the mast, and both should be grounded back to the battery.

Bonding and grounding are two different things. The ground wire off the radio should really be considered a chassis bonding wire. If we considered a sailboat like an aircraft, a radio chassis is bonded to the chassis, as is everything else that is conductive, and all of it is tied to the battery ground. If you ever see aircraft with those little wires hanging off the trailing edges of the wings and tail, they are static whips. The idea isnt really for lightning protection, as much as for better communication. By bonding the radio chassis and antenna to the mast, the mast, and all conductive parts of the system, become part of the antenna, greatly expanding its reception range, its clarity, and reducing static.

CaptGregg · Jul 3, 2012

Even though my tech support responsibilities are with VHF radio/video transmission equipment, bonding and grounding in marine environment is new to me, I just got through with a discussion with one of the repair technicians concerning VHF antenna ground plane in a fiberglass marine vessel environment and how to best implement a ground plane.

Chris Patterson · Jul 3, 2012

Cuz, don't over think the situation. A "no ground plane' antenna is just that, it requires no plane. These things are generally 5/8 wave resonating elements, and they work fine. Hell, you can screw it into fiberglass and it'll work. Constructing a "real" ground plane on a boat would look like a Russian fishing trawler, and it's unnecessary. I once used one on a 2 meter radio, (that was even tuned to 162 mega-hertz), and was SLAMMING repeaters 50 miles away. Right now, I'm only using a 5 watt hand held, because on a little day boat like these, on the east coast, it works great. On a bigger boat, with more radio room, and getting offshore, I use two V.H.F. radios, S.S.B., and sat-coms. As it should be.
But, why not. A standard marine radio will hit around 25 watts. With a coat hanger sticking out of the back of it, it'll easily talk 10 miles.

As far as lightening goes......I've read mounds, and volumes on it. And still have no clue. The cool thing about it is, is the experts that STUDY the damn phenomenon, and they don't either. It's like the bolt than dodged every cruising boat in the marina, to strike a jon-boat lashed to the end. And those lightening "dissipaters", (I know it's not a word), that I think Forespar sells, they sound like a good idea. And they did as well to the owner that had his struck twice, both times ignoring the VHF aerial beside it.
My best guess is, is to throw a wire over the side, that's connected to a shroud, to give the charge somewhere to go besides through your hull sounds like the best bet.

That, and getting away from the silly boat...

CaptGregg · Jul 3, 2012

Chris,

That's what I love about you, you can simplify anything!

Stu Jackson · Jul 3, 2012

Just a lightning strike...of information.

People who get hit are the ones who say ligthening.

Chris Patterson · Jul 4, 2012

Aw Stu, ya killed me man. I generally try to watch my spelling, and structure, but I missed that one. I would edit and fix it, but I think I'll let it ride. Reminds me again, I'm not that smart. And know little more about it, than to fly a key on a kite. (By the way, Franklin never did that, and the guy that DID try it, got killed).

I hope this doesn't mean I'm somehow cursed..

Stu Jackson · Jul 4, 2012

Chris, just kiddin'

I always thought Ben Franklin's hair was that way because he actually flew that kite!

jfrench · Jul 4, 2012

There's no ground on our plastic boats unless you want to try to protect your mast from lightning strikes (which is largely impractical). Run two wires to power your stereo: Pos (+) and Neg (-). That's all there is to it.

anchorclanker · Jul 4, 2012

jfrench said:
There's no ground on our plastic boats unless you want to try to protect your mast from lightning strikes (which is largely impractical). Run two wires to power your stereo: Pos (+) and Neg (-). That's all there is to it.

Youve completely disregarded the ground plane, which exists everywhere. Use it, or dont use it, but it cannot be stated that it does not exist.

Also, bonding and grounding are two separate things. You could have a bonded system that is not electrically grounded for lightning.

jfrench · Jul 5, 2012

Let's keep it simple. The question was: "Does anyone know where to attach a ground wire to on an '81 C22 ?" The answer is: there is no "ground" in a plastic boat. Each circuit is separately wired with a Positive and a Negative wire, run directly to the electrical panel (where a common negative bus serves as the closest thing we have to a "ground").

Since the fiberglass hull is non-conductive, there is no bonded "ground" as in a car or a boat trailer. And, since the hull insulates the on-board electronics from grounding to "earth" (the water in which it's floating), there's no way to wire his radio to "earth" ground except to install a wire that contacts the water. Such a connection would provide little benefit for his stereo.

There is little need for "grounding" in our boats, because they only have 12 volt systems. On a bigger boat with 120 volt shore power or a 120 volt generator, you need to worry about "bonding" and "earth" grounding of the system for safety. On our 12v-only boats the only possible need for grounding is lightning protection for the mast. A heavy wire connected to the mast and mounted in contact with the water, could prevent a hole from being burned in the hull below the water line as the lightning finds its own path to "earth" ground. The lightning would instead (hopefully), travel along the wire and safely exit into the water with just some minimal melting of fiberglass along the length of the ground wire. This is more likely in "new design" boats that have a metal mast support.

Perhaps the stereo manufacturer provides a connection for bonded grounding in order to eliminate electrical noise from the engine ignition system or an engine mounted alternator. Again, no way to implement it on a Cat 22, short of running a bonded ground wire to the outboard -a bit of overkill for a Cat 22.

Stu Jackson · Jul 5, 2012

KISS makes good sense. However, you mention the word "grounding" when talking about the mast, which is incorrect. The ground on a 22 foot sailboat with an outboard engine is not the electrical panel, it is the negative post of the battery bank. For a boat with an inboard engine the DC ground is the engine.

Do not connect the mast to the boat's electrical ground system.

It is really important to use the correct terms when trying to explain stuff.

Please see Reply #s 2 & 6 in this topic.