GFCI Breakers vs. GFCI Receptacles

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Scott69

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Springfield, OH
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Construction Management
First off, I am a construction manager, not an engineer. Been doing this for 30 years, so more versed on electrical than most CM's.

Had an inspection on a project in Royal Oak, MI for a dialysis clinic. The inspector is requiring a 5 mA protection for all GFCI breakers due to a 65 kAIC rating. They are saying this cannot be done inside the panel (breakers) and suggested installing GFCI receptacles. Understand that I can install a GFCI receptacle at first device location on circuit. Eaton did perform a power study for faults.

Looking for clarification on:
1. Is this a code requirement?
2. Explain why a GFCI breaker is not sufficient.
3. Was the electrical engineer at fault for specifying GFCI breakers?
 
Can you go back to the engineer and confirm the required AIC rating for the branch breakers in that particular panelboard.
Even with a system rating of 65k, there' a decent possibility the rating (series) of the branch breakers is 10k or 22k which would match GFCI breakers.
 
The project was designed using the 2017 NEC. All circuits wired with 12 Cu. All breakers are Easton 20A, 1P GHBGFEP. Voltage drops range from 0.24% to 2.39%.
 
Not saying they aren't but as Gus points out there is a chance (and in my experience) the branch circuit breakers are probably lower than 65k
 
Scott69 said:
The project was designed using the 2017 NEC. All circuits wired with 12 Cu. All breakers are Easton 20A, 1P GHBGFEP. Voltage drops range from 0.24% to 2.39%.
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I believe that's a 277V, equipment ground fault protection circuit breaker.

It can't be used to provide ground fault protection for personnel.
 
I assumed the OP was talking about 120V receptacle circuits, but maybe not. Not sure why they would have 480/277V panelboards for 120V circuits.
 
david luchini said:
I believe that's a 277V, equipment ground fault protection circuit breaker.

It can't be used to provide ground fault protection for personnel.
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After reading the product data, I believe you are correct. The Interrupting Rating (kA Symmetrical) Volts table lists 65 at 240Vac, but states nothing for 120Vac.
 
david luchini said:
I believe that's a 277V, equipment ground fault protection circuit breaker.

It can't be used to provide ground fault protection for personnel.
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Yep.

Many times 277V breakers are applied at 120V as one way to get higher fully rated AIC levels.
 
Scott69 said:
After reading the product data, I believe you are correct. The Interrupting Rating (kA Symmetrical) Volts table lists 65 at 240Vac, but states nothing for 120Vac.
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The catalog says the operational voltage for the breaker is 240V-305V. I don't think you could use it on a 120V system.
 
IMO, definitely time to go back to your engineer. Apparently he has specified some high fault current breakers in a series that doesn;t have GFCI and, although the solution of a GFCI receptacle would likely solve the problem, most GFCI receptyacles have a AIC of 10k which may in itslef be problematic.
 
# 1 AHJ should give you the code reference they are referring to. NEC 517 etc.
# 2 Are these circuits in Category 2 area of the facility? What are they being used for there are different application , wiring methods, devices, etc.
# 3 EOR should clarify
 
augie47 said:
IMO, definitely time to go back to your engineer. Apparently he has specified some high fault current breakers in a series that doesn;t have GFCI and, although the solution of a GFCI receptacle would likely solve the problem, most GFCI receptacles have a AIC of 10k which may in itself be problematic.
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It would only take about 8 ft of #12 wire (4 ft hot & 4ft neutral) to limit the short circuit current at a GFCI receptacle to less than 10kA in a 120V circuit.
But to prevent insulation damage that occurs above 150°C, the current would need to be limited to ≈ 2.7kA assuming that the breaker trips in 1 cycle on a short circuit. That would require the total conductor length for a short circuit to be at least 28 ft (a 14ft cable or conduit).
 
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