100 amp shore power

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Carlos Pelaez

Carlos Pelaez

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Location
Miami Beach, FL
Occupation
Electrical Contractor
Customer wants to install a pedestal with a 100amp connector for a 87' boat. I offer him to install two 50amp outlets and to buy the adapter that combines both connectors to one 100amp buy he said that he had issues with those before. He wants to be able to connect the 100amp cord from the boat directly to the dock pedestal. Any ideas?
 
I guess the first thing, can the service and panel accept the expansion?

Will the dock accept the expansion? What kind of dock is it (construction)?

Are the existing circuits all home runs or are they loop feeding pedestals? If they are loop feeding, you may be able to modify some of the pedestals and get your 100-amp outlet.
 
This is a new pedestal. The service can handle it. My concern is that all power beyond the seawall has to be ground fault protected with a tripping sensitivity of 30mA. There are no breakers 100a gfci or gfpe. What is the solution?
 
Just poking around, you may need to use a 100a shunt-trip breaker and a GFP module, Schneider makes something like that but I didn't look too closely at the data sheet. Might have to use a 3-pole breaker for this to match the module.
 
zbang said:
Just poking around, you may need to use a 100a shunt-trip breaker and a GFP module, Schneider makes something like that but I didn't look too closely at the data sheet. Might have to use a 3-pole breaker for this to match the module.
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This looks a really good solution. Thank you so much.
 
GoldDigger said:
FWIW there is also a TIA to that section of the 2017 Code that specifies greater than 30ma trip level, but it applies only to protection for the entire marina.
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Can you please expand on this? And I guess it would not apply in this case, right? But I would still love to know about it. Specially since I am in Miami Beach and have to deal with dock power all the time. Thanks!
 
I think a Y adapter paralleling two GFPE outputs would be doomed to failure. Getting the output currents on the phases to symmetrically combine so that there's less than than 30mA/50A = 0.06% imbalance on each outlet to prevent tripping would be very difficult. An even if you did, just a little extra contact resistance through one pin could then cause it to trip.
 
The '17 Code stated all
Carlos Pelaez said:
Can you please expand on this? And I guess it would not apply in this case, right? But I would still love to know about it. Specially since I am in Miami Beach and have to deal with dock power all the time. Thanks!
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The '17 Code required all shore power overcuurent devices to have GDP protection 30ma or less. This included feeders.
A TIA allows the feeders to be coordinated with the individual shore power receptacles and not have 30ma protection.
The TIA would not remove the requirement for a 100 amp shore power outlet to have 30ma protection.
 
synchro said:
I think a Y adapter paralleling two GFPE outputs would be doomed to failure. Getting the output currents on the phases to symmetrically combine so that there's less than than 30mA/50A = 0.06% imbalance on each outlet to prevent tripping would be very difficult. An even if you did, just a little extra contact resistance through one pin could then cause it to trip.
Click to expand...
Very good point!
 
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