The 2023 NEC, Article 230.85 requires an emergency disconnect for one- and two-family dwelling units. A common question we receive is whether a whole-house generator transfer switch can serve as the emergency disconnect.
The short answer: Yes it can.
However, after contacting multiple generator manufacturers, we found that most, if not all, exterior whole-house transfer switches are labeled as “service equipment” and not listed as “suitable for use as service equipment”. Because of this, they can serve as both the emergency disconnect and the service disconnect, but they cannot be labeled as “Not Service Equipment”.
This means the following installation rules apply:
- The exterior whole-house transfer switch must be field-labeled as:
- “Emergency Disconnect” and
- “Service Equipment”
- Grounding electrode conductors (GECs), Ground rods, structural steel, water pipe, etc., must terminate in the transfer switch, not the interior panel.
- A 4-wire feeder (hot-hot-neutral-ground) must run from the transfer switch to the main house panel.
- The interior panel now becomes a sub-panel, so neutrals and equipment grounds must be isolated in that panel.
This setup satisfies 230.85 for emergency disconnects and complies with service equipment requirements in Article 230.
If you have questions about emergency disconnects, transfer switch installations, or need an electrical inspection, feel free to contact us anytime.