ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB: The Classic Live Audio Board => Topic started by: Art Williams on March 17, 2016, 08:54:13 pm

Title: GFCI on a cruise ship...
Post by: Art Williams on March 17, 2016, 08:54:13 pm
I've done a couple of gigs on cruise ships...I always seem to have a problem of some sort with my AC DISTRO... all of my distros are GFCI protected...however it seems at will when on a cruise ship GFCI's are not happy...I understand a cruise ship does not have an actual ground but the problems that I have...should I just get non GFCI distros?
Title: Re: GFCI on a cruise ship...
Post by: John Roberts {JR} on March 17, 2016, 09:10:26 pm
No  figure it out...

What is the problem..?  If GFCIs in your distro trip, more than 5mA (?) is leaking into ground from mains.

If ship GFCIs are tripping because of your GFCI distro that doesn't make sense.

Is there something about the sea (salty) air?

JR
Title: Re: GFCI on a cruise ship...
Post by: Stephen Swaffer on March 17, 2016, 09:31:45 pm
I've done a couple of gigs on cruise ships...I always seem to have a problem of some sort with my AC DISTRO... all of my distros are GFCI protected...however it seems at will when on a cruise ship GFCI's are not happy...I understand a cruise ship does not have an actual ground but the problems that I have...should I just get non GFCI distros?

Actually, a cruise ship probably has the best ground of any venue you will ever work in.  However, the "ground" has absolutely nothing to do with the function of the GFCI's.

JR is correct-narrow it down and figure it out.  I have had cheap receptacles cause a GFCI to trip in somewhat humid environments.  It would not be a stretch to think that something in your distro/gear has a leakage path that is pushed over the edge in a humid environment.
Title: Re: GFCI on a cruise ship...
Post by: Erik Jerde on March 18, 2016, 07:25:14 am
I have had cheap receptacles cause a GFCI to trip in somewhat humid environments.  It would not be a stretch to think that something in your distro/gear has a leakage path that is pushed over the edge in a humid environment.

Sounds like it's time to crank up the shower and do a little at home testing.
Title: Re: GFCI on a cruise ship...
Post by: Josh Millward on March 18, 2016, 03:04:40 pm
Also, it is important to note that a typical outlet on a ship is not exactly the same thing as the 120VAC outlet at your home in the USA.

The biggest difference is on the "Hot" and "Neutral" wires. There is 120VAC difference between the hot and neutral, but they are each only 60V away from ground. It is the same sort of thing that you find with the typical household 240VAC single phase service in a house, the voltage is just scaled down to provide 120VAC instead of 240VAC.

Now, I believe your GFCI outlets should still work fine in this situation, provided you do not have neutral shorted to ground anywhere. Do you have any outlet strips with surge protection built into them in your setup? You should cut the MOV's out of that outlet strip anyway, but if one shorted between neutral and ground, this could be your problem.
Title: Re: GFCI on a cruise ship...
Post by: John Roberts {JR} on March 18, 2016, 04:04:42 pm

Now, I believe your GFCI outlets should still work fine in this situation,
Yes, GFCI doesn't care, unless >5mA goes anywhere other than between line and neutral
Quote
provided you do not have neutral shorted to ground anywhere. Do you have any outlet strips with surge protection built into them in your setup? You should cut the MOV's out of that outlet strip anyway, but if one shorted between neutral and ground, this could be your problem.
+1 It may not be a hard short... I found one cheap outlet strip with "protection" that was leaking 20mA to the ground....

JR