Ground Fault Protection for 480/277 1200 A service?

SunFish

Member
Location
ID
I am currently working on a new construction project where we will be interconnecting a solar system with a 480/277 1200 A service. We're planning to do a backfed breaker. According to 230.95 services over 150 V to ground and rated 1000 A or more have to have GFP on the main service and therefore our solar also has to have GFP per 705.32.

The electrician on the project is telling me they are not installing GFP with the main service breaker because it isn't required for 480/277 services rated 1200 A or less. Am I missing an exception somewhere? I'm hesitant to call the electrician out on this but also want to make sure the customer is getting a code compliant installation. The AHJ enforces 2017 NEC.
 

packersparky

Senior Member
Location
Wisconsin
You are correct.

230.95 Ground-Fault Protection of Equipment. Ground-fault
protection of equipment shall be provided for solidly grounded
wye electric services of more than 150 volts to ground but not
exceeding 1000 volts phase-to-phase for each service disconnect
rated 1000 amperes or more. The grounded conductor
for the solidly grounded wye system shall be connected directly
to ground through a grounding electrode system, as specified
in 250.50, without inserting any resistor or impedance device.
The rating of the service disconnect shall be considered to
be the rating of the largest fuse that can be installed or the
highest continuous current trip setting for which the actual
overcurrent device installed in a circuit breaker is rated or can
be adjusted.
Exception: The ground-fault protection provisions of this section shall
not apply to a service disconnect for a continuous industrial process
where a nonorderly shutdown will introduce additional or increased
hazards.
 
I am currently working on a new construction project where we will be interconnecting a solar system with a 480/277 1200 A service. We're planning to do a backfed breaker. According to 230.95 services over 150 V to ground and rated 1000 A or more have to have GFP on the main service and therefore our solar also has to have GFP per 705.32.

The electrician on the project is telling me they are not installing GFP with the main service breaker because it isn't required for 480/277 services rated 1200 A or less. Am I missing an exception somewhere? I'm hesitant to call the electrician out on this but also want to make sure the customer is getting a code compliant installation. The AHJ enforces 2017 NEC.
Note also it's not the service size that triggers the GFP requirement, it's the service disconnect size. You could have a large service with multiple service disconnects under the 2-6 rule and if they were all under 1000a, no GFP required.
 

Cow

Senior Member
Location
Eastern Oregon
Note also it's not the service size that triggers the GFP requirement, it's the service disconnect size. You could have a large service with multiple service disconnects under the 2-6 rule and if they were all under 1000a, no GFP required.
I agree.

We've installed many services larger than 1000 amps with multiple service disconnecting means rated less than 1000 amps just so we didn't have to deal with GFP.
 

SunFish

Member
Location
ID
Ok thanks everybody. The service disconnect is the 1200 A main breaker so it sounds like they should have GFP for this...
 
Top