12.1 General Disconnecting Means Principles

Start with the Supply and Equipment Type

A disconnect question is first a classification problem. Determine whether the conductors are a utility service, an outside feeder to another building, a motor branch circuit, or an HVAC circuit. Then use the article for that installation. The presence of a switch somewhere upstream does not establish that its location, rating or function satisfies the equipment rule.

Visibility and Accessibility

In sight requires visibility and a distance of 50 ft or less. A disconnect 20 ft away around an opaque corner is not in sight. Conversely, visible equipment 80 ft away fails the distance condition. Do not confuse this test with readily accessible, which concerns reaching and operating equipment without obstacles or other prohibited actions.

The installation article determines when a lockable disconnect or another exception may be used. The definition of in sight does not create a general exception for every remote switch.

Outside Supplies to Another Building

For an ordinary outside feeder, locate the rules in this sequence:

1. 225.30: determine whether the proposed number of supplies is permitted. Additional supplies need to meet a stated allowance.
2. 225.31: identify the required disconnecting means at the building or structure served.
3. 225.32: apply the location requirements and applicable exceptions.
4. Check the number, grouping, rating and suitability requirements in the rest of Article 225, including any dwelling-specific outdoor emergency-disconnect provisions.

Suppose a house panel supplies a detached garage. The breaker at the house protects and disconnects that feeder at its source. You must still evaluate the garage's required disconnect. A main-breaker panel at an appropriate garage location may perform that function when it meets the applicable requirements; a main-lug panel without a suitable disconnect is not automatically equivalent.

2026 change: Under 225.31, the emergency disconnect for an outside supply must be within sight of the building or structure. If that disconnect is installed away from the building, the Code also addresses a disconnect at the nearest point of conductor entrance. Read the complete conditions together with 225.32 and 225.41. For one- and two-family dwelling services, the outdoor service-disconnect requirements are in 230.70; do not use the older separate 230.85 rule as the current citation.

Switching Equipment and Wiring Devices

Article 404 continues to cover equipment such as disconnect switches. Snap switches and dimmers are now in Article 406, Part III. For a wall-device problem, start with 406.38 for accessibility/grouping and 406.46 for rating/use. For larger switching equipment, start with Article 404 and the equipment-specific article.

An enclosure rating does not establish that the enclosed switch can interrupt every load. Verify the device's voltage, current, load and interrupting characteristics. An isolating device must not be treated as a load-break disconnect unless it is rated and permitted for that duty.

Reference: Minnesota Board of Electricity’s review of the published 2026 NEC changes.