The National Electrical Code (NEC) specifies disconnect switch locations to ensure safety and accessibility. According to NEC 430.102(A) & (B), motors and motor controllers must have a disconnecting means located within sight (within 50 feet and visible) unless an exception allows a remote location with proper lockout provisions. NEC 240.24(A) & (B) requires overcurrent protection devices, including disconnects, to be readily accessible and not installed in bathrooms or hazardous areas unless specifically permitted. NEC 404.8(A) states that disconnects must be mounted at a height between 2 and 6.5 feet above the working surface unless an exception applies. For HVAC equipment, NEC 440.14 mandates a disconnect switch within sight of the unit. In commercial and industrial settings, disconnects must also comply with NEC 110.26, ensuring adequate working clearance for maintenance.

A breaker lock may be used instead of a disconnect switch in certain situations, but it depends on the application and NEC requirements. According to NEC 430.102(B) Exception, a circuit breaker with a lockable device can serve as the disconnecting means for motors if it is capable of being locked in the open position and remains under the control of qualified personnel. Similarly, NEC 110.25 states that any disconnecting means required by the code must be designed to accept a lockout device. However, for equipment like HVAC systems (NEC 440.14) and some industrial machinery, a separate, within-sight disconnect switch is still required for safety.

The minimum depth of clear working space in front of a disconnect switch is 3 feet, but this may increase based on voltage and the presence of live parts on opposite sides. The width of the working space must be at least 30 inches or the width of the equipment, whichever is greater. The height must be at least 6.5 feet or the height of the equipment. If the disconnect is in front of a panel or other electrical gear, additional clearance may be required for safe access. Specific equipment, such as HVAC systems, may have additional placement requirements.

The 6-switch rule means that disconnecting a building or structure must consist of no more than six disconnect switches grouped in the same location. These can be six separate breakers or switches in a panel or individual disconnects installed together. The rule applies to main service disconnects but does not limit the number of branch circuit breakers within a panel. In the 2023 NEC update, this rule was modified to require a single service disconnect in most new installations, except for specific exceptions.

Consider the voltage and current rating, ensuring it matches the electrical system and load requirements. Determine whether a fusible or non-fusible switch is needed; fusible disconnects provide overcurrent protection, while non-fusible types are used for isolation only. Check the number of poles based on the circuit configuration, such as single-phase or three-phase systems. Select a NEMA or IP-rated enclosure suitable for the environment, such as outdoor, wet, or hazardous. Verify compliance with NEC and UL standards, especially for specific applications like motor control (NEC 430.102) or HVAC equipment (NEC 440.14). Ensure the disconnect has a lockout/tagout (LOTO) feature if required for safety. Lastly, confirm proper mounting options and space availability for installation.