705.31 Location of Overcurrent Protection.

Could the switch connected to the inverter output circuit be of the blade type, without fuses? What is the minimum required rating of the disconnect switch if the fuses were only required to be rated 30 amps?
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Could the switch connected to the inverter output circuit be of the blade type, without fuses? What is the minimum required rating of the disconnect switch if the fuses were only required to be rated 30 amps?

Code Change Summary: A new code section was added to require overcurrent protection within 10 ft. of where the electric power production source conductors are connected to the service.

Until now, there really has been no code language that provides any specifics on how to make a line side tap (a connection from the inverter output circuit of the PV system to conductors ahead of the service disconnect) for a PV system. The previous code language in 230.82 states that a PV system is allowed to connect ahead of the service disconnect but provides no insight on how it must be done or where any required overcurrent protection must be located.

In the 2014 NEC®, new language requires overcurrent protection for electric power production source conductors (such as the inverter output circuit), connected ahead of the service disconnect, to be located within 10 ft. of the point where the electric power production source conductors are connected to the service.

Below is a preview of the NEC®.  See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on the “free access” tab and select the applicable year of NFPA 70 (National Electrical code).

2014 Code Language:

705.31 Location of Overcurrent Protection. Overcurrent protection for electric power production source conductors, connected to the supply side of the service disconnecting means in accordance with 705.12(A), shall be located within 3m (10 ft) of the point where the electric power production source conductors are connected to the service.

Informational Note: This overcurrent protection protects against short-circuit current supplied from the primary source(s) of electricity.

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705.31 Location of Overcurrent Protection.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

If using a line side tap to interconnect the PV system to the service conductors ahead of the service disconnect, which of the following is true?

A: Only one central inverter is permitted.
B: Overcurrent protection for the PV system inverter output circuit must be located within 10 ft. of the point where the PV source conductors connect to the service.
C: Overcurrent protection for the PV system inverter output circuit must be located within 50 ft. of the point where the PV source conductors connect to the service.
D: The OCPD for the PV system inverter output circuit cannot be closer than 10 ft. from the point where the PV conductors connect to the service.
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