Inverter Grounding

AKDAVE · Posted: Wed Jan 17, 2007 10:14 pm Post subject: Inverter Grounding

I am installing a 1000 watt inverter in my 2003 CD 25 and am not sure how to ground the unit. How have others grounded these? This DC stuff is more complicated than what I've done before.

Dave

mikeporterinmd · Posted: Wed Jan 17, 2007 11:09 pm Post subject:

There should be a 120V ground (green) as part of the connection, and
then there should be a case ground that goes to the 12V neutral along
with the 12V positive and negative connections.

But, part of this has to do with whether the 120V ground is connected
to the 12V neutral. Nigel Caulder goes to great lengths to beat it
into anyone reading his book that these should be connected for
safety's sake, even though it can lead to galvanic corrosion.

The arguement is basically what happens if the 120V hot shorts
to the 12V neutral (or positive). Without a path back to ground
to trip cause an over current condition and trip the 120V breaker or
GFCI, the 12V neutral will be hot with 120V, just waiting for someone
to touch it.

Anyhow, this is a good book to get. I think the title is Boat Owners
Electrical and Mechanical Guide or something similar. The 3rd
edition is available from Amazon.

Mike

journey on · Posted: Thu Jan 18, 2007 12:17 am Post subject:

I installed a Xantrex Prosine 1000. There was only 12 VDC positive and negative connections. I haven't ever seen a 12 VDC neutral. I've seen chassis grounds that are supposed to be connected to a ground (read: something touching water,) but that's to get rid of noise (RF, alternator, etc.)

On the AC side, just connect the green wire to the inboard side of the AC ground isolator, which C-Dory put on my C-25. An AC neutral is used on a 3 phase system isn't it? Or have I also got that wrong?

Boris

mikeporterinmd · Posted: Thu Jan 18, 2007 8:33 pm Post subject:

There is a 12V neutral bonding system and then there is 12V negative.
12V negative is connected to the 12V neutral bonding system.

If you have a galvanic isolator, then I'm not sure how to do the hookup.
Best to look it up. If you have a real isolation transformer, then that might
also be different.

Anyhow, the purpose of connection to the 12 neutral with a 120V/12V
device is safety. Could be RF, too, I guess.

Mike