Disconnects for solar and other power sources
Every solar, battery or other power source needs a disconnect that separates its output from other systems. The 2023 NEC lists seven requirements for it, and one disconnect may serve several sources if it meets all seven.
What the code requires
Section 705.20 requires a way to disconnect a power source's output circuit conductors from the conductors of other systems. One disconnect may serve more than one source.
The disconnect must be one of four types: a manually operable switch or circuit breaker; a load-break-rated pull-out switch; a power-operated or remote-controlled switch or breaker that can be operated by hand at the device and opens if control power is lost; or a device listed or approved for the use.
It must open all ungrounded conductors at the same time, be readily accessible, and be operable from outside with no exposed live parts. It must clearly show whether it is open or closed, and its ratings must suit the maximum circuit current, the available fault current and the voltage. If both the line and load terminals can be energized while it is open, it must be marked with a warning that both sides may be live.
On the job
- A disconnect that can be energized from both sides while open does not comply without the shock-hazard warning marking.
- A disconnect that is not readily accessible does not comply.
- One disconnect can serve several sources only if it meets all seven requirements.
What changed in 2023
The 2023 NEC renamed 705.20 Source Disconnecting Means, allowed one disconnect to serve several power sources, dropped the 2020 item on enclosure doors that expose live parts (cutting the list from eight requirements to seven), and spelled out the both-sides-energized warning instead of pointing to 690.13(B).
In California
California's only amendment applies to facilities under OSHPD jurisdiction, such as hospitals: the disconnect may be inside or outside the building and must be placed as close as practical to the point where the conductors cross into or out of OSHPD jurisdiction. Nothing changes for typical homes or businesses.
Related sections
- NEC 705.11: Supply-side (line-side tap) solar and battery connections
- NEC 706.15: Disconnects and emergency shutdown for battery systems
- NEC 230.85: Outdoor emergency disconnect for homes
- NEC 225.41
- NEC 110.25
Where this comes from
Send a photo. Get a real answer.
Text is fastest. If you smell something burning or see smoke, call 911 first and keep away from the panel.
Kyle Robert Anderson KBC Electric · CSLB #1073066 · C-10 Electrical · Licensed since 2021