My GFCIs trip when tested on inverter power. Grounding and inverters is a complicated subject. "Real" marine certified inverters with internal cut-over switches will work one way and the various cheap consumer units not intended to be hardwired could work any possible way. Joe DB Coquina
-----Original Message----- From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of S Thomas via CnC-List Sent: Wednesday, September 23, 2015 1:00 PM To: cnc-list@cnc-list.com Cc: S Thomas Subject: Re: Stus-List GFCI Outlet Most inverters sold now (I know, not all) are isolated from the ground, and should NOT have one side grounded, but the new GFCIs are not dependent on the existence of an earth ground. It is legal to install 3 pronged GFCI receptacles in older houses without separate ground wires where I live, because the GFCI works by detecting any difference in the current flowing in the 2 wires. There is no separate earth ground available in that situation. The GFCI circuits might also be affected by the harmonic content of the "quasi" sinewave inverters, but I have not tried it. The waveform from these inverters is a rectangle, tuned to minimise the third harmonic. Not all loads like that sort of power, but everything I have tried so far seems to work ok. Steve Thomas ----- Original Message ----- From: "Syerdave--- via CnC-List" <cnc-list@cnc-list.com> To: <cnc-list@cnc-list.com> Cc: "syerd...@gmail.com" <syerd...@gmail.com> Sent: Wednesday, September 23, 2015 12:17 Subject: Re: Stus-List GFCI Outlet > worked for Hubbell for 21 years.... There is no standard specifying what > constitutes marine grade, so, the difference could simply be the label. > The GFCI, despite being a safety device, is built offshore to a price, > driven that way by the residential construction market. The marine > variant might be upgraded in some basic ways (visible plating) or might > not, and this will vary by manufacturer. Years ago, manufacturers > built better stuff and did not focus so much on standardization and cost. > To be fair, most customers are not willing to pay for better, when good > enough will do. > GFCIs have provision to protect downstream devices, but they must be wired > accordingly. The GFCI first, and the downstream receptacles connected to > the purpose-specific terminals on that GFCI. Note that this means that > the cumulative ground leakage for the downstream portion are now "seen" by > the GFCI, and "nuisance tripping" could be a result. > Are you worried about safety or compliance? > I think the biggest safety issue is not in the head but somewhere else, > probably when working on the boat. (how often do you use 110v appliances > concurrent with the presence of standing water in the head? At home > sure, but in the boat? In two years I have never used the receptacle in > the head. ) > IMO to do this right, install a GFCI receptacle or module as far upstream > as possible, but after the 15A branch circuit breaker (in the 33ii there > are two circuits, port and starboard, I think.) protecting as a priority > the receptacles where you are most likely to be using 120v - fans, tools. > . > One thing to check, and I don't know the answer, is whether or not you are > protected on circuits energized by an inverter. GFCIs don't or at least > didn't always work without a real ground reference. (Gensets as an > example - years ago this created a great deal of confusion WRT workplace > safety practices.) > Dave > _______________________________________________ Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com _______________________________________________ Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
