Having a GFCI protect an entire dock is nuts. If the dock had 10 boats then each could only leak 3 mA on average. And if the GFCI tripped it would take down the whole dock. I don't think many docks are wired this way.
David
I have posted this here before but it always bears repeating...
The current NFPA 70 / NEC requirements
Article 555 Marinas & Boatyards, which rolled out in 2011, required a
100mA ground fault protection level for marina dock feeds. In the current 2017 NFPA 70 / NEC 555 this maximum level droped from 100mA to
30mA.
The Problem With the New Mandates:
#1 NFPA 70 / NEC requirements do not mandate 30mA protection at each
dock pedestal (it's optional), 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. Under the new 2017 NEC 555 standard it appears as though an entire marina can be protected by a 30mA GFI.. (I have submitted request for clarification to NFPA but as of yet nothing) 30mA would be fine if it was mandated
at each pedestal, meaning only the offending boat would be out of power, but it appears they did not roll it out like this.
When I originally wrote this I was waiting for a customers phone to cool down so we could continue troubleshooting his shore system via video messaging. He was in the BVI and could not find a decent electrician to save his life. As of this writing we'd found on-board AC neutral bonded to AC Earth and his two 30A shore inlets had a 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 perhaps not requiring 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 de-powers all the boats on that string and creates a lost power situation to all of those vessels, just as my customer had done, at no less than 3 or 4 marinas since leaving Maine. I had fully warned him of this but because he'd only ever visited "grandfathered" marinas he declined to correct the wiring issues.
The 2011 100mA 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 new NFPA / NEC ground fault requirements for marinas is 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 2011 NFPA/NEC requirement was not at the power pedestal/individual boat level and the 30mA dock pedestal placement appears to be
optional..
If you're a marina owner and your electrician tells you you need to purchased and install one 30mA GFI to be compliant or 125 30mA GFi's (one for each slip/pedestal) which way to the think the marina owner is going to wire it.....???
#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. Incorrectly wired vessels create problems for everyone at an
up-to-code marina.
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.
Bottom Line? Improperly wired vessels, vessels not wired to ABYC standards, can cause high rates of nuisance tripping of shore ground fault interrupters. This issue was less nuisance prone at 100mA and is going to be a MAJOR MESS at 30mA unless marinas choose to install the GFI at the dock pedestal level.
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. Improperly wired inverters, generators, transfer switches, automotive grade battery chargers, auto grade inverters, improperly wired hot water heaters etc. are all hot button areas where a neutral/grounding bond may be hiding. Some boat owners & terrestrial based electricians have also been known to place a jumper between neutral and grounding bus.
#3 The Rx?
Marina Rx: Marina's who want happy customers should ideally install a a 30mA ground fault device
at each pedestal. This is the ONLY way to minimize nuisance tripping of boats other than the offending incorrectly wired vessel.
The GFI device (GF=Ground Fault Interrupting) should be installed at each pedestal so one boat or transient vessel can not take out an entire dock or entire group of vessels due to dangerous wiring practices. Adding a GFI device at each pedestal was in compliance with the 2011 NFPA 70 / NEC and actually
exceeded the bare minimum requirements. Clarification on the 2017 standard I am still waiting on, but it appears pedestal level is not a mandated requirement and it can be upstream of the pedestal...
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. These ground fault devices should not be daisy chained to the load side of the GFI and should serve only that pedestal, if keeping happy customers is what they desire.
Marina's also need to comprehend and understand that
GF 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 now that NFPA & NEC have dropped it to 30mA, because the drop to 30mA appears to not require protection at the individual pedestal level. If someone reads the standard
differently, or has submitted a request for clarification, please let me know.
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 simply do it right and install a 30mA device at each pedestal, this way
only the miswired customer is left without power.
It should be noted that if you follow the ABYC standards, and your boat is wired with a 30mA ELCI (an ABYC E-11 requirement), then you won't have to worry about tripping a 30mA pedestal...
When a marina is re-wired, or the wiring touched by a professional, they now need to become in compliance with the current shore based standards. The mandatory shore based NEC/NFPA standards extend to the dock pedestal receptacle, and the
voluntary ABYC standards begin at the shore power cord set.
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 article 555 requirements. Now that it has officially dropped to 30mA, to protect multiple pedestals, it will become a complete debacle..
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.
If you are at a marina with frequent GFI nuisance trips ask them to opt for pedestal level 30mA GFI protection as opposed to marina, branch or finger level protection.
