Rapid Shutdown Code Changes for PV Systems

NEC Code Changes for Rapid Shutdown & What it Means for You.

In 2014, the NEC instituted code 690.12 in regards to rapid shutdown of PV systems. The code was implemented in order to protect First Responders from the dangers of an energized PV system, even after the AC service has been shutoff. More than half of all states have adopted the code change, and further changes and amendments are on the horizon for 2017.

GRID TIED SYSTEMS

Rapid Shutdown requirements came to play in the 2014 code, and most grid-tied inverter manufacturers and installers started adopting relatively quickly. Electrical inspectors also came quickly up to speed, but the language within the code left some questions unanswered. For the 2017 code changes, the NEC elected to simplify and clarify some elements, which also allows many inspectors to come up to speed and manufacturers to streamline their offerings to match.

Fronius Rapid Shutdown Add On
Fronius Grid-Tie RSD Add On

Backwoods is here to offer solutions and support to meet the changing requirements of the electrical code. Many inverters that we carry now have proprietary RSD accessories available, as shown to the left. Most Grid-Tied inverters have a solution readily available and at a decent price.

OFF-GRID and BATTERY BACK-UP SYSTEMS

Off-Grid and Hybrid systems utilizing storage are also included in the code changes. Companies such as Schneider and Outback have proprietary solutions for some of their off-grid inverters. Others don’t have something that ties in under the same branding. For those systems, we have third-party options offered by Midnite Solar which have additional features that allow inverters with on-board AC outlets to continue to work during power outages. (Such as the SMA Sunny Boy line).  A third party solution may also be a great way to retrofit an existing system should you need to add RSD. Keep in touch via our website as more solutions become available.

MidniteSolarRapidShutdownSystem
Midnite Solar RSD Diagram with Birdhouse

As stated above, these code requirements affect both grid-connected and off-grid homes. Standalone ground mount or pole mounts should be excluded, however we have run into inspectors that challenge that thought. Understanding the code and how it applies to where the PV is installed and how the conductors (wires) are run within the dwelling and between the array and AC source is important to explain. The requirement states that all PV System Circuits installed on or in buildings shall include a rapid shutdown function that controls specific conductors that meet the following conditions:

  1. Systems that include PV system conductors (wires) of more than 5 feet inside a building or 10 feet from a PV array.
  2. Controlled conductors shall be limited to not more than 30 volts and 240 volt-amperes within 10 SECONDS of shutdown.
  3. Voltage and power shall be measured between any two conductors and between any conductor and ground.
  4. The rapid shutdown methods shall be labeled as such: PHOTOVOLTAIC SYSTEM EQUIPPED WITH RAPID SHUTDOWN (in white, capitalized, reflective letters on a red background). – Backwoods has labels available for this purpose.
  5. Equipment that performs the rapid shutdown shall be listed and identified.

As we design systems for individuals that require rapid shutdown, we will include the appropriate solution for your situation and the inverter choice that was made.