Marina

F

Flash Gordon

Member
Location
Washington
The new marina dock has the sub panel main breaker 600a gfci 30MA breaker trip at the sub panel on the dock when one of the 30a 120v 30MA pedestals trips at the pedestal thus no selective coordination and the whole dock gos black.

The service on the beach is GFPE protected 100 MA and holds.

All the branch circuits in the sub panel on the dock are standard breakers now.

So when the pedestal 30a 30MA gfci ocp trips the branch circuit ocp in the sub panel holds and the main breaker in the sub panel on the dock trips taking out all the other boats .

I’m confused. Not my installation I have no dog in the fight. Why would the installer not just put a standard main breaker in the sub panel and then remove the standard 30a breakers in the sub panel and replace them with 30a 30MA gfci breakers ?

Is the installer trying to save money buy not buying a sub panel full of 30a 30MA gfci breakers?
California installation
 
Flash Gordon said:
...
So when the pedestal 30a 30MA gfci ocp trips the branch circuit ocp in the sub panel holds and the main breaker in the sub panel on the dock trips taking out all the other boats .
...
Click to expand...

Is this 30A 30mA ground fault protection (GFPE) inside the pedestal provided by a breaker? If so, then the circuit in the subpanel supplying this breaker qualifies as a feeder. 555.35(A) specifies a 100mA level GFPE be provided for feeders. It appears to me that you could have the main breaker in the subpanel be a 100mA GFPE instead of 30mA.
 
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Yes at the pedestal 30mA 30 A. Up stream in the sub panel a standard breaker. Up from that the Main in the sub panel 30Ma GFCI. The beach breaker is GFPE.

It confuses me why there’s no selective coordination.

The pedestal when tripping takes the feeder panel main with it.
 
The installer says the dock main breaker is 100mA and the Pedestal is a 30A 30mA.

Yet when the guys boat was energized the 100mA main breaker tripped as well as the Pedestal.

My curiosity is why is the main tripping .
 
What is the system type 120/240? And what is the available fault current at the 100ma breaker and the 30ma?
How many ohms is the boat fault N-G?

UL does not specify a trip curve for Class B 'GFPE' breakers / marina GF monitors that I am aware of, I suspect the manufacturers use the same electronics as a class A GFCI so likely similar curve as a class A GFCI.
If a vessels ground fault is not a bolted short but rather a 'wiring error' or low impedance steady G-N fault somewhere around 550 ohms then a class A GFCI should trip in about 2 cycles or 33.3ms. I am guessing at that level both breakers the 30ma and 100ma will have the same or similar ground fault 'trip curve' for lack of a better term.
You may need a device like this to pre-test vessels:
marinaee.com

Vessel Ground Fault Check Unit - Marina Electrical Equipment

The Vessel Ground Fault Check Unit ISO solves many important issues since it isolates the test vessel from the marina’s wiring.
marinaee.com marinaee.com
and as @ramsy said in fewer words boot the offending boat off the dock.
 
Two things i will not do..
Engage a battle of intellect with a italian.
Help any family or friend with boat, rv or trailer wiring, especially after being screwed up by a "professional"
Nope. No thanks.
 
tortuga said:
What is the system type 120/240? And what is the available fault current at the 100ma breaker and the 30ma?
How many ohms is the boat fault N-G?

UL does not specify a trip curve for Class B 'GFPE' breakers / marina GF monitors that I am aware of, I suspect the manufacturers use the same electronics as a class A GFCI so likely similar curve as a class A GFCI.
If a vessels ground fault is not a bolted short but rather a 'wiring error' or low impedance steady G-N fault somewhere around 550 ohms then a class A GFCI should trip in about 2 cycles or 33.3ms. I am guessing at that level both breakers the 30ma and 100ma will have the same or similar ground fault 'trip curve' for lack of a better term.
You may need a device like this to pre-test vessels:
marinaee.com

Vessel Ground Fault Check Unit - Marina Electrical Equipment

The Vessel Ground Fault Check Unit ISO solves many important issues since it isolates the test vessel from the marina’s wiring.
marinaee.com marinaee.com
and as @ramsy said in fewer words boot the offending boat off the dock.
Click to expand...


If there are 3 or more shore power receptacles the marina is actually required to have one available.

555.35(B)
 
ChesterDawg said:
Why not until Jan 1 2026?

It's in the 2020 NEC and 2022 CEC
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Grasshopper must get familiar with forum rules. Long ago forum member's declared the Fungible Rule:

Fungible Rule: When you have skin in game, code is fungible.

Thant means if your boat trips the dock, code doesn't apply to you.

And, after 1/1/26, new effective date becomes 1/1/27.
 
ChesterDawg said:
If there are 3 or more shore power receptacles the marina is actually required to have one available.

555.35(B)
Click to expand...
Was not actually aware of that section, thanks for sharing.
tortuga said:
and as @ramsy said in fewer words boot the offending boat off the dock.
Click to expand...
Did not realize eviction was actually recommended in 555.35(B), until reading that Informational Note No. 2
 
If you want to dive into the weeds of boat wiring many older vessels have what we call a 'isolation transformer', to isolate shore power from boat power (good) including the equipment ground (bad for us good for the old boat)
Here is a diagram form one such system the show attaching the shore power equipment ground to primary side transformer shield.
So the secondary side (the boat side) only has a path back to the shore via the water.
However a fault (or leakage) between the secondary windings and the shield wire (shore power equipment ground) makes the water the fault current return path.
From what I read this once common practice is no longer approved due to the fault current ground loops. There are galvanic isolators that people install between the shore power equipment ground and the boat frame 'ground' that accomplish corrosion prevention and keep the fault clearing path.
This article by David Rifkin goes into more detail:

1760896823592.png
 
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ChesterDawg said:
Why not until Jan 1 2026?

It's in the 2020 NEC and 2022 CEC
Click to expand...
Assuming you are talking about testing boats for leakage. 555.35(B)(2)(D) which says:
Leakage Current Measurement Device. Where more than three receptacles supply shore power to boats, a listed leakage current measurement device for use in marina applications shall be available and be used to determine leakage current from each boat that will utilize shore power. The listing requirement for the leakage current measurement device for use in marina applications shall become effective January 1, 2026.

So I didn't see the prefix about the "listing requirement" part of this, I thought the whole rule wasn't effective until 2026. But it may be difficult to find a listed test device if there is no listing standard.

The NEC has a habit of getting ahead of itself requiring things like GFCI's for AC units or pool pumps that don't work because of high frequency leakage so they need to make new listing standards. Those don't happen overnight and in the mean time we suffer with all the misbehaving devices.
 
suemarkp said:
Assuming you are talking about testing boats for leakage. 555.35(B)(2)(D) which says:
Leakage Current Measurement Device. Where more than three receptacles supply shore power to boats, a listed leakage current measurement device for use in marina applications shall be available and be used to determine leakage current from each boat that will utilize shore power. The listing requirement for the leakage current measurement device for use in marina applications shall become effective January 1, 2026.

So I didn't see the prefix about the "listing requirement" part of this, I thought the whole rule wasn't effective until 2026. But it may be difficult to find a listed test device if there is no listing standard.

The NEC has a habit of getting ahead of itself requiring things like GFCI's for AC units or pool pumps that don't work because of high frequency leakage so they need to make new listing standards. Those don't happen overnight and in the mean time we suffer with all the misbehaving devices.
Click to expand...

Interesting. They must have changed that since my book was published.
 

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I *think* the reason there is no cheap and easy way to test this like measuring continuity form the shore power cord ground pin to the hull or engine is they typically have a 'galvanic isolator' DC blocking diode in the equipment ground that will block the 9V DC from your meter.
This is the correct method:
1760907887687.png
 
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