Tuesday, May 12, 2015

Nine NEC Code Updates for Solar Installations

Solar Installations and the NEC Code
The popularity of sustainable energy has been driven in part by the improvement and increased use of photovoltaic (PV) energy systems that convert sunlight into electrical energy. The opportunities for the use of PV systems in new construction, in both commercial and residential buildings, has been driven by improvements in its technology advances and by the growth of the industry itself and the resultant diversity of available products.
The 2014 update of the National Electrical Code (NEC) includes a number of changes related to the installation and operation of PV systems. With the growing use of PV systems, trained electrical personnel should be particularly aware of these code changes and how they govern installations. These changes are found primarily in NEC Article 690.

"Qualified person"

For instance, one important change that should improve safety is that the code now requires installation of all PV systems and their associated wiring and interconnections be performed by qualified personnel (690.4). ”Qualifed Person” is specifically defined in Article 100, and this definition identifies that a qualified person has received safety training to recognize and avoid hazards involved. One PV installation qualification program is UL’s Photovoltaic System Installation Training course and Certification Exam.

Rapid shutdown

One new section to the NEC is 690.12, that requires PV systems installed on buildings to have a rapid shutdown function. Rapid shutdown protection is intended to reduce potential hazards and limit exposure to energized PV wiring and equipment to allow emergency first responder / fire fighters to perform work outside the energized area of the PV array. For the 2014 NEC the rapid shutdown protection zone is outside of a perimeter of 3 meters (10 feet) from all sides of a PV array and 1.5 meters (5 feet) into a building. The controlled conductors that extend outside of this protection zone must be limited to 30 V or less and 240VA within 10 seconds after initiation.
All rapid shutdown equipment is required to be listed and identified and the installation shall include the required plaque or directory alerting individuals to the presence of the rapid shutdown system.

Ground fault protection

The 2014 Code also expands the 690.5(A) ground fault protection section. Ground fault systems are required to detect a ground fault in the PV array current-carrying components and conductors, including conductors that are intentionally grounded. The system or device shall interrupt the flow of the fault current, clearly indicate the fault and be listed as PV ground fault protection.

Separating wiring

The wiring section of the PV code contains extensive revisions and additions. Section 690.31(B) has been rewritten to clarify that PV source circuits and output circuits cannot be in the same cable tray, outlet box, junction box, cable, raceway with similar circuits for non-PV systems unless conductors are separated by a partition. To make this clear, the section requires source circuits, output circuits and inverter input and output circuits for PV systems be clearly identified as such as any point of termination, connection and splicing. When components of two or more PV systems occupy the same junction box or raceway, they must be grouped separately by cable ties or similar means.
NEC Code and Solar Installations

Maximum voltage raised

Section 690.7(C) now requires that Part IX applies to installations with a maximum system voltage of 1,000V rather than the previous threshold of 600V.

Electric vehicle charging

A new Section was added to Article 690 addressing electric vehicle charging systems integrated with PV systems.

Arc fault for all

Arc-fault direct-current circuit protection, addressed in Section 690.11, now includes language that expands its use to essentially all PV arrays, where the 2011 NEC only required PV arc-fault circuit protection for installations on buildings.

Warning labels

In Section 690.31(G-3), markings and labeling for PV power source conductors now must specifically state, “Warning: Photovoltaic Power Source” in capital letters wherever appropriate.

Overcurrent devices

There were also revisions to Section 690.9 for overcurrent protection that now require listed PV overcurrent protective devices that are specifically evaluated for operation within the severe PV array operating environment and have the appropriate voltage, current, and interrupt ratings for their use in system circuits  These overcurrent devices are required to be accessible but not readily accessible (as defined in Article 100).

Continued evolution of the NEC

New editions of the NEC are published every three years, but updating the Code is a continuous process. The First Draft of the 2017 NEC, which will be published next year, is already underway. Those of us working on the current edition recognize that participation by stakeholders drives the continued evolution and we are committed to making the 2017 edition as effective as possible.
Written by Tim ZgonenaUL principal engineer, Distributed Energy Resources Equipment and Systems
- See more at: http://www.solarnovus.com/nine-nec-code-updates-for-solar-installations_N8810.html?utm_source=Solar+Flares+-+The+Newsletter+of+Solar+Novus+Today&utm_campaign=9a71b5ecd6-Solar_Flares_12_May_2015&utm_medium=email&utm_term=0_727e2679c6-9a71b5ecd6-420693765#sthash.C9v6gJfm.dpuf

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