I don't mean to hijack the thread. Maybe my comments will help the OP: If a boat was improperly wired wouldn't the tripping be consistent? In the slip, I can run everything on board sometimes with no problems. Wouldn't the problem appear on the trailer in the yard too? The yard outlet is also a GFI. On our dock, each pedestal has 4 outlets. Each outlet protected by a circuit breaker. The CBs do not trip.
I appreciate the comments.
Not necessarily because the leakage could be below 5mA and it is not until another boat plugs into the same GFCI "circuit" that the GFCI trips because the cumulative leakage has now exceeded 5mA.
Plugging a vessel into a 15A or 20A household receptacle is
NOT proper
shore power. This is problem #1.
Problem #2 gets a lot more complex. I have posted this before but will post it again...
The current NFPA 70 / NEC requirements
Article 555 Marinas & Boatyards, which rolled out in 2011, requires a
100mA ground fault protection level for marina docks. In the upcoming 2017 NFPA 70 / NEC 555 this maximum level is reportedly going to drop from 100mA to
30mA. The OP is trying to plug his vessel into a
5mA trip level GFCI..
(Copy & paste of a previous reply)
The Problem With the New Mandates:
#1 NFPA 70 / NEC requirements do not mandate protection at each
dock pedestal, which would be the only prudent way to adopt or phase this into an entire industry where the safety standards are
voluntary and arguably
grossly ignored.
As I type this I am currently waiting for a customers phone to cool down so we can continue troubleshooting his shore system via video messaging. He is in the BVI and can't find a decent electrician to save his life. So far we've found on-board AC neutral bonded to AC Earth and his two 30A shore inlets have common neutral bonding. Somewhere in his travels he had a failed 8kW generator ripped out, by some hacks, who left a ghost transfer switch and ran the ghost wires to where ever they found an open terminal. It is a freaking mess, a mess I repeatedly tried to talk him into fixing before he headed off cruising. "seems to work" he'd say.... He began complaining of issues when his vessel began tripping
up to code marina's and shutting entire docks down. The non-transients at these marinas were none too happy and the marinas finally told him
not to plug in..
As a result of NFPA/NEC not requiring 100mA or 30mA ground fault protection at the pedestal level, for each boat, any vessel plugging into a dock pedestal that is protected by an
upstream ground fault device can create nuisance trips for every boat on that same feed. This = BAD (safe, but bad)
Shore based ground fault devices that cover multiple pedestals (boats), can result in a nuisance trip that depowers all the boats on that string and create a lost power situation to all of those vessels, just as my customer has done, at no less than 3 or 4 marinas since leaving Maine.
This NFPA / NEC roll out has already cost boaters significant $$ in destroyed battery banks etc.. Unfortunately the boaters who lost out may not have been the ones who created the problem just the recipient of what I often refer to as
Darryl & Darryl wiring, for those old enough to get the Newhart reference.. No offense to any Darryl's out there....
The NFPA / NEC ground fault requirements are only serving to expose the
horrendous wiring that has gone on in the marine industry for far too long. Even if your boat is properly wired, to ABYC standards, you can still suffer the consequences of Darryl & Darryl hack jobbing their own boat because the NFPA/NEC requirement is not at the power pedestal/individual boat level.
For what it is worth I have very infrequently come across an owner who believed it was their boat creating the leakage or corrosion issues. In almost all cases it starts out as "
someone else's problem" until the fault is found on-board...
#2 Far too many boats out there are not wired to meet or exceed the ABYC safety standards. The NFPA / NEC could really care less about this,
it's not their issue. When you plug an
incorrectly wired vessel into the new NFPA /NEC shore standards, requiring ground fault protection, it can now become everyone's issue not just the problem vessel.
Boats that are not wired to current ABYC standards, as a group, have very, very high ground fault percentages. For example the number of boats I measure with AC ground
ing (GREEN) and AC Neutral (WHITE)
bonded on-board the vessel (A huge
no-no) is in the range of 35-40% +/-. This is
INSANE, but it is the reality of a
voluntary standard that has gone largely ignored by boat owners, or DIY wiring done by local dock-experts who think they know more than the standards organizations, and far too many folks who call themselves marine electricians..
Bottom Line? Improperly wired vessels, vessels not wired to ABYC standards, can cause nuisance tripping of shore ground fault interrupters. This sill be rarer at 100mA or 30mA and quite a common occurrence at 5mA...
The sheer age of many vessels also means some of them have equipment that is so antiquated that it too creates an
inadvertent neutral to grounding bond on-board the vessel..
#3 The Rx?
Marina Rx: Marina's who want happy customers should ideally install a 100mA or 30mA ground fault device at each pedestal, not 5mA, so one boat can not take out an entire dock or entire group of vessels. This is in compliance with NFPA 70 / NEC and actually
exceeds the minimum requirements. By installing a ground fault device at each pedestal this prevents Darryl & Darryl's stellar wiring job from taking out your boat when they create a nuisance trip.
Marina's also need to comprehend and understand that
leakage is additive. If we have ten boats each leaking 4 mA, which is not even enough for each boat to trip an individual 120V 5mA GFCI, those ten boats together can trip a single 30 mA ground fault device.
Marina's should prohibit vessels that cause a nuisance trips, from plugging into their system, until the fault has been corrected. If a vessel is tripping a 100mA threshold device (and this is not due to additive leakage) this creates a very dangerous potential for electric shock drowning.
The issue & mess of nuisance tripping will only get worse when the NEC drops to 30mA in 2017..
Marina's need to fully understand the new requirements and be trained on how to conduct spot audits and to check for individual vessel issues that would otherwise create problems for the rest of their customers. Or do it right and install a 30mA device at each pedestal, this way only the offending customer is left without power..
When a marina is re-wired they now need to become in compliance with the current shore based standards. Shore standards extend to the dock pedestal receptacle, and ABYC standards begin at the shore power cordset.
This problem of nuisance tripping is only going to get worse, much worse as time goes on and more and more marinas become in compliance with the NFPA 70 / NEC requirements. Once the code drops to 30mA, to protect multiple pedestals, it will become even worse.
Boat Owner Rx: Wire your vessel to the current ABYC standards and you will no longer create dangerous situations, power loss or dead batteries for those around you who do have properly wired boats.
Two Easy Tests for 120V 30A Service (these two tests barely scratch the surface but its a start):
1- Use a high resolution AC clamp meter set to measure A or mA. Extech, Yokogowa and Fluke all make excellent AC leakage clamp testers. Ideally every marina should own one. Power up your on-board AC devices (hopefully all of them) & place the clamp around your shore power cord. The reading should be 0.0A. Any reading above this is indicating an amperage imbalance between the hot and neutral AC conductors and indicating that this missing current is leaking elsewhere eg: into the water..
2- One of the easiest tests or starting points is to physically unplug your vessel from the pedestal and be sure your inverter is decoupled from DC so it does not auto-invert. Make sure any manual transfer switches are set to SHORE. Now test for continuity between AC WHITE/Neutral and AC GREEN/Earth/Grounding pins at the shore end of the cord or at your on-board grounding bus and neutral bus.. There should be no continuity.
If you find issues you are unsure of I would suggest bringing in a professional....
