How much clear space does an AC disconnect need?

36 inches deep, 30 inches wide, and 6 feet 6 inches of headroom per NEC 110.26(A). The width does not need to be centered on the disconnect.

Can the condenser sit in front of the disconnect?

No. The unit and its lines cannot occupy the 36 inch deep working space in front of the disconnect. Mount the disconnect beside the unit with clear ground in front.

How far can the disconnect be from the AC unit?

NEC 440.14 requires it within sight of the equipment, which means visible and no more than 50 feet away, and readily accessible.

What clearances do you need around an AC disconnect?

An air conditioner disconnect is equipment likely to require examination and servicing while energized, so NEC 2023 110.26(A) applies. You need working space 36 inches deep measured out from the face of the disconnect, 30 inches wide, and 6 feet 6 inches of headroom. The space must be clear from grade to the required height, and the disconnect door has to open at least 90 degrees.

Side to side, the 30 inch rule

The 30 inches of width does not have to be centered on the disconnect. The enclosure can sit at the left edge or the right edge of the space, as long as one continuous 30 inch width exists in front of it. The disconnect also must not be so close to a corner or an obstruction that the door cannot swing open fully. Two disconnects side by side can share overlapping working space under 110.26 as long as each one individually has a compliant 30 by 36 inch zone.

The condenser is the usual violation

The most common failure is the condensing unit itself, or its refrigerant lines, sitting inside the 36 inch depth in front of the disconnect. Mount the disconnect to the side of the unit or on the wall far enough away that the working space lands on clear ground. Fences, gas meters, hose bibs, and shrubs count as obstructions the day of the inspection even if the shrub was small when you roughed it in.

Within sight of the unit

440.14 requires the disconnect to be within sight of the air conditioner and readily accessible, and within sight means visible and not more than 50 feet away. Behind the unit on the same wall is fine; inside the garage on the other side of that wall is not. The disconnect may not be mounted on the panels the tech must remove to service the equipment.

Field notes

Set the disconnect around 4 to 5 feet to the handle so it is comfortable to operate, keep it out of the space directly over the lineset penetration, and leave the 110.26 zone in front of it clear of the unit pad. On tight side yards, mounting the disconnect above the condenser height on the wall next to the unit usually solves the depth problem cleanly.