Hopefully the inverter will come with very clear instructions on how to
handle ground and neutral.

For normal power, ie shore power, this is the US code:

"The National Electrical Code ( NEC ) requires the AC source to have a Neutral 
to ground bond
and that there be only one such bond in the entire AC system."

So only at the distribution panel is there a bond between neutral and ground. 
They should
never be connected together intentionally at the load. This document covers 
grounding and
bonding, may also cure insomnia.

https://www.engineereducators.com/docs/groundingandbonding2-2.pdf

Grounding an AC system is done to limit the effect of a lightning strike, maybe 
an upstream
over voltage fault. Bonding the green wire that comes in a three prong plug ( 
also called a
ground ) to Neutral at the distribution panel is to ensure a low resistance 
return path for
a fault. So if anything happens the desired effect is that a hot to ground 
short will occur
which in turn will cause an over current surge blowing the circuit breakers.

A person can be electrocuted even with a properly installed and grounded AC 
system
without the circuit breakers tripping.

Unless an inverter has some specific design that uses a ground bonding the 
Neutral and
ground together is not going to do much. Check out the last Q&A from Xantrex 
here:

http://www.xantrex.com/documents/tech-doctor/universal/tech4-universal.pdf

Similarly with an inverter connected to a battery that is not grounded a GFCI 
should
never trip. Theoretically in a floating system the power has to come out of the 
Hot
lead and return in the Neutral. There will never be a ground fault to trip a 
GFCI.
There is no ground.

I suppose an inverter manufacturer could create a third connection back to the
power circuit Neutral that bypasses the GFCI. A short to that wire would cause
an imbalance and trip the GFCI. Then you would be connecting a floating
Neutral to the loads "ground" which may be exactly what the Xantrex article says
not to do.

Michael Brown
Windburn
C&C 30-1
 




From: Ron Ricci <rvri...@gmail.com> 

David, 
 
I've followed some of this thread and have a few concerns where some have 
mentioned using an inexpensive inverter.   
 
Using an inverter that is not intended for marine use or not properly 
grounded can cause problems.  An inverter can produce short duration spikes 
which exceed the insulation rating of most wires.  This becomes an issue in 
wet areas and will cause insulation failure.   
 
There are other issues relating to inducing corrosion.  A friend who 
coincidentally keeps his boat in RI and is the technical support guru for a 
company that sells variable frequency drives (inverters for AC motors) had 
to replace his propellers when he used an inverter he bought from Harbor 
Freight.  It was probably fine for anything other than marine use.  
 
If the neutral on the inverter is not grounded, the neutral can kill you 
regardless of the presence of a GFCI.   
 
Just my thoughts, 
 
Ron Ricci 
S/V Patriot 
C&C 37+ 
Bristol, RI 
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