LINE SIDE INTERCONNECTION

[SIRSPARKSALOT]

A question came up today...We have (2) 500kW interconnecting with an existing service. The interconnection point is on the line side of the service and it is being made in a piece of gear...1600A main and (2) 800A backfeed breakers. One of the facility engineers stated that since the new gear is technically a service and over 1000A it needs to have GFCI protection on the main.

I explained that the whole reason for backfeeding on the line side was to be ahead of the existing GFCI main and that there is no requirement to have this GFI'd.

Am I correct?

 

[ron]

If your interconnection is actually a service (which I would think it is), then check 230.95.

 

[Smart $]

A question came up today...We have (2) 500kW interconnecting with an existing service. The interconnection point is on the line side of the service and it is being made in a piece of gear...1600A main and (2) 800A backfeed breakers. One of the facility engineers stated that since the new gear is technically a service and over 1000A it needs to have GFCI protection on the main.

I explained that the whole reason for backfeeding on the line side was to be ahead of the existing GFCI main and that there is no requirement to have this GFI'd.

Am I correct?

If your line side interconnection is through (2) 800A breakers, each breaker is considered a service disconnect... and each is under the 1000A requirement.

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 600 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.

 

[shortcircuit2]

Sparks...how did this work out for you?

One large scale install in my area could NOT tie in line side because of cold sequence metering. They had to change out the main panelboard to comply with 705.12(D)(2)

If you have that much solar to backfeed, should not have it been designed with its own service setup without GFP?