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More info need from Thom

Old 01-31-2003, 10:43 AM
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Default More info need from Thom

I will remove the in line fuse on the electronics and come off of a fuse pannel. One more question concering the grd. Are you talking about coming from a screw on the back of the radio that holds the cover on (chassis grd)to neg. grd. of battery or to the grounding plate? Thanks Bob
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Old 01-31-2003, 01:52 PM
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Bob,

When I say chassis ground what I mean is what you described, a wire comming off of either a case screw in the radio going to a ground plate (ground to earth, not directly to the battery or the DC system by some other less direct means). If there is some sort of grounding lug on the radio that is even better of course. These things aren't really necessary in almost any case but they never hurt anything either and if you have a gound plate you might as well use it. Where they shine is if you have strange little blips comming through the speakers or see some really odd fire-works on one of your display screens from time to time.

Thom

"For every complex question, there's a simple answer. And it's wrong."
(--H. L. Mencken)
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Old 01-31-2003, 02:40 PM
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Default More info need from Thom

Thom, this is essentially my setup , but I have a quick question. My statpower charger has the typical +/-/gnd connections on the a/c side. I haven't connected the ground connection to the gfci outlet, only the +/-. I did run the earth ground connection around my double pole braker to the gfci, but not to the charger.

Should I leave it as-is or run the ground to the charger. I don't have an isolator.

Thanks.

** sigh **
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Old 01-31-2003, 03:26 PM
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Default More info need from Thom

Gerg,

Connect that AC-side ground from your battery charger to the ground terminal on your GFI outlet, which in its own turn is connected to the ground side of your shorepower inlet, which is connected in its own turn to the ground wire in your shorepower cord, which is connected in it own turn to the shorepower supply tower , which is connected in its own turn to the breaker panel back at the marina, which is connected in its own turn to the earth by way of their grounding rod sunk deep into the earth (with any sort of luck at all). And that's really the point. When the marina was wired they connected the AC system you happen to be plugged into into good old mother earth. What you don't want is any AC electricity you are using to find its way to mother earth by way of any in-water connection on your boat. If you do there will be a difference in electrical potential between one route and the other, meaning the one you might supply on the boat and the one the marina supplied back at their breaker panel. It is the use of two different paths to ground with two different potentials that causes metal on boats to go away to parts unknown. Sort of an in-water electroplating business you didn't know you had got yourself into.

That's the problem with folks making the mistake of thinking that they should connect the ground from their DC system to the ground from their AC system (Gerg, on your battery charger you are Only talking about connecting the "ground" wire on the AC side of your charger, not on the DC side). When this is done, be it intentionally or by mistake, what it does is create a ground to earth from your AC system through the running gear and there will always be a difference in potential if you do that. Of course there is no way to know beforehand which way the potential will go - sometimes you don't loose anyting from your boat, but end up with a nice coating of other people's boats plated onto your external gear.

God, I hope I didn't screw this up to much !

Thom

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(--H. L. Mencken)
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Old 01-31-2003, 05:36 PM
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Default More info need from Thom

Thom, thanks for clearing that ground wire question up. I wanted to connect it for safety but wasn't sure what that would do in terms of ground looping. The Xantrex unit is supposed to provide some level of galvonic isolation so I wasn't worried about the dc leaking back (and there are no other connections to the dc side except on the dc out of the charger), I was getting confused easily though.

I'm actually somewhat familiar with electroplating. My way far back degree is in ChE and my first job was in a printed wiring board shop (lots of plating). Now I work in marketing in high tech and play with boat repairs - how far we stray.

btw, do you have any reccomendations for an inverter (dc to ac)?

** sigh **
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Old 01-31-2003, 05:41 PM
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Default More info need from Thom

Ok, so I'm a screw-up. I could have sworn I asked this question under the new charger question, and not under this question.

I hate it when that happens. Sorry gang.

** sigh **
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