Code Change Summary: Revisions were made regarding the use of a PV disconnect that is suitable for use as service equipment (SUSE).

Some disconnect switches have been evaluated and found to be suitable for use as service equipment while others have not. Listed disconnect switches marked “suitable for use as service equipment” are required by the UL Standard to have provisions for bonding the grounded terminal bar to the enclosure. This is generally the main bonding jumper for a disconnect switch used as service equipment.

In the 2014 NEC^®, it was clear that a PV system disconnecting means was not required to be suitable for use as service equipment. This rule created confusion when dealing with interactive PV systems utilizing a PV system disconnect switch downstream of a line-side tap connection to the service conductors. The line-side tap is technically an extension of the service conductors since there is no overcurrent protection other than that provided in the PV system disconnecting means.

In the 2017 NEC^®, the rules have been reversed. Now, If the PV system is connected to the supply side of the service disconnecting means as permitted in 230.82(6), the PV system disconnecting means shall be listed as suitable for use as service equipment.

There is still a gray area when it comes to figuring out what to call a PV system disconnecting means using a line-side tap connection. Some say that the switch is a service. Some say that it is not to be included in the six-switch rule when determining the maximum number of switches permitted at a service location in section 230.71. It is likely to see additional revisions in the 2020 code cycle to clear up the confusion.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC^® edition of NFPA 70.