Ac question

[off the rock]

Hi GUYS
Tried to start a new thread but keeps bringing me back here
Anyway was going to see if anyone would have any suggestions on my AC problem I have a 25 crownline CR-250, last weekend went to Arkansas and hooked up to shore power everything was fine until I turned on AC it tripped the GFE box
at the dock only when turning on AC tried another plug 3 stalls down and on one plug AC again tripped GFE on bottom plug of same outlet it worked very strange tried various plugs around the dock and they all tripped when I turned on AC, about to give up when this one plug worked, how would I troubleshoot this problem don't want to go to other docks and trip GFE plugs.. Thanks Andy
BTW AC works fine on generator

 

[Bifflefan]

Re: Ac question

What is a GFE? Do you mean the Ground Fault Circuit Interrupter GFCI or GFI?
The GFI's may be weak. They get that way with age and being tripped a lot. Also the motor in your a/c unit is getting older and is pulling a higher surge to get it started. It could also be the cord you are using to plug into the dock has a loose connection, or it may be a small gauge cord that can't handle the surge.

 

[Grandad]

Re: Ac question

GFCI's do vary somewhat in their sensitivity, even from new. Their "target" trip is supposed to be when 5 milliamps (.005 amps) of current leaks to ground. Manufacturers are given a tolerance up to 6 milliamps to meet certification standards. Since you tripped a number of the GFCI's, I would presume that your AC unit has wiring insulation deteriorated enough at some point for current of sufficient quantity to cause the tripping.

I'd start by making sure that all of the wiring is clean and dry. I expect that the motor is a hermetically sealed unit such that you can't access motor windings as you might with other motors. So, if the wiring is clean and dry, but GFCI's still trip, I'd have the unit tested by a repair shop. If the motor itself is the problem, you're likely into replacing the unit. If you're adept at using an ohmmeter, you could check the resistance between conductors and ground. By Ohm's law, a resistance less than 24,000 ohms will cause more than 5 milliamps to flow to ground when fed from 120 volts. It's probably not the most reliable way to test, since the resistance may vary as the unit vibrates in operation. A more effective test device is a dielectric strength tester that only specialized labs and trained personnel might have. - Grandad

 

[UncleWillie]

Re: Ac question

If the boat trips 5 GFI's and works in one;
The assumption should be that the one that doesn't trip is bad, and NOT that the other five are bad.

GFI's trip when the current in the HOT lead and the NEUTRAL Lead are not the same.
This means that some of the current is returning through the GROUND.
It has Nothing to do with Startup/Surge Currents. This is NOT a Popping a Breaker situation.

You can safely assume that there is a problem with the AC Unit.
This is not just an annoyance, it is a real and serious and potentially deadly problem. Do Not take this problem lightly.
The popping GFI is saving you, and warning you that action needs to be taken.
It may be a simple matter of corrosion that can be resolved for very little expense. But it need to be found and resolved.
Putting a "Penny Under the Fuse" would be a big mistake.

 

[glenn property of pam]

Re: Ac question

if it trips a good gfci but will run with out a problem on a bad gfci then I would take a good look at all the neutral wires on the boat. Unplug from the cord then open the 120v breaker panel and tighten every white wire. Also access the wiring junction box on the air-con unit and tighten the wires including the neutral and ground. If you see any moisture on any electrical parts, post back where you are seeing it. Air-con can cause a draft in a conduit/junction box due to changes in temp between 2 different areas which will suck in warm air and cause moisture on the wires and terminals in areas like the back of the shore receptacle. Moisture will trip a good gfci where a bad gfci will just flash the moisture off.
Like unclewille said the gfci is warning you that theres a problem and its not a good idea to ignore the warning.

 

[off the rock]

Re: Ac question

if it trips a good gfci but will run with out a problem on a bad gfci then I would take a good look at all the neutral wires on the boat. Unplug from the cord then open the 120v breaker panel and tighten every white wire. Also access the wiring junction box on the air-con unit and tighten the wires including the neutral and ground. If you see any moisture on any electrical parts, post back where you are seeing it. Air-con can cause a draft in a conduit/junction box due to changes in temp between 2 different areas which will suck in warm air and cause moisture on the wires and terminals in areas like the back of the shore receptacle. Moisture will trip a good gfci where a bad gfci will just flash the moisture off.
Like unclewille said the gfci is warning you that theres a problem and its not a good idea to ignore the warning.

Thanks guys guess I will try to dig into AC wiring and breaker panel and tighten connections.....