Thinking ahead

[oldsparky52]

I'm involved in supervising (hired as a consultant) a residential contractor that will be wiring a marina that is being replaced. The AHJ is requiring GFP to be installed on the mains (5 different services, big marina). In order to keep a GF on a boat from taking out the service for that dock, GFP at 30ma will be installed at the pedestals for all receptacles that boats plug into (the GFP on the service will be 100ma and have a short time delay to allow the GFP at the pedestal to work before taking out the service).

The dock house will be on one of the docks, and be fed out of the sub panel on the dock. The feeder will have GFP in order to drop out the dock house before taking out the service GFP. The fuel system will be fed out of the dock office.

I have a relationship with the fuel installer, and I'm going to wire the fuel system (while advising/supervising the dock wiring). So I started thinking, what are the chances of a fuel system having some kind of GF when it's turned on/off during the operation? I'm having nightmares of getting the complaint that "every time I turn on the dispenser, we lose power to the dock office". LOL, I worry a lot, huh.

Any thoughts/concerns? I know that it should all work fine, but ...... this is a new design for me to install/supervise.

 

[mgookin]

I think the '17 code is going to lower that 100mA threshold. FYI
Not sure where your state is on the cycle or when you intend to apply for your permit.

 

[augie47]

TN is still on the '08 Code but has been enforcing a "marina code" for over a year now and the 100ma protection is required. None of the installs with which I have some familiarity have fuel dispensing so I can't help with that but I do want to commend the design using the 30ma protection for shore power. There are numerous marinas in this area that have only the 100ma service or feeder protection and the contractors are constantly making service calls where one boat "fault" is taking out the entire dock/marina. I have been amazed at the number of boats the have neutral-ground mix or similar problems.
A lot of folks are having afterthoughts now about their decisions not to use the individual 30ma protection

 

[jumper]

I think the '17 code is going to lower that 100mA threshold. FYI
Not sure where your state is on the cycle or when you intend to apply for your permit.

OP is in NC, NC is 2014.

Yes, 2017 is lowering it to 30ma and changing the wording.

View attachment 16013

 

[winnie]

For these sorts of systems, are GFPE breakers available that can provide 'restraining signals' for the upstream breakers?

I've never dealt with ground fault systems with multiple levels of protection and restraining signals; I simply remember reading about them when studying something else for a project, so I don't know what is actually available.

-Jon