NEC Working Space Requirements: Table 110.26(A)(1) Explained

The 2020 NEC (NFPA 70) requires a clear space in front of electrical equipment at least 3 ft deep, 30 in. wide and 6½ ft high. Depth grows to 3½, 4 or 5 ft with higher voltage to ground, depending on what's behind you. Find your depth with the calculator below.

It applies to equipment of 1000 V or less to ground likely to need examination, adjustment, servicing or maintenance while energized. Examples: panelboards, switchboards, switchgear and motor control centers.

Working space depth calculator: Table 110.26(A)(1)

Depth depends on two things: the voltage to ground and what faces the live parts across the aisle. At 150 V or less to ground, it's 3 ft whatever is across from you.

Measure from the exposed live parts, or from the front of the enclosure or its opening if they're enclosed.

Example: in an existing building, you replace a dead-front 480Y/277 V panelboard that faces another dead-front panelboard across a 3½ ft aisle. Condition 3 calls for 4 ft. Add written procedures that keep both from being open at once, with only authorized qualified persons (workers trained on the equipment and its hazards) servicing them. Then 110.26(A)(1)(c) allows the Condition 2 depth of 3½ ft, and the aisle passes.

The three conditions in plain words

• Condition 1: live parts on one side, nothing live or grounded on the other. Also applies when live parts on both sides are guarded by insulating material.
• Condition 2: live parts on one side, grounded parts on the other. Concrete, brick and tile walls count as grounded.
• Condition 3: exposed live parts on both sides, such as equipment facing equipment. In existing buildings where equipment is replaced, 110.26(A)(1)(c) allows Condition 2 under written procedures that keep both sides from being open at once.

Voltage to ground: 480Y/277 V is 277 V to ground, and 120/240 V is 120 V to ground. On an ungrounded system, use the highest voltage between any two conductors.

Width, height and other NEC working space requirements

Dedicated equipment space: 110.26(E)

Switchboards, switchgear, panelboards and motor control centers also need a dedicated space, separate from the working space.

• Indoors: the equipment's width and depth, from the floor to 6 ft above it or the structural ceiling, whichever is lower.
• Keep out: piping, ducts, leak protection equipment and anything else foreign to the electrical installation.
• Allowed: a suspended ceiling with removable panels, and sprinklers.
• Outdoors: grade to 6 ft above the equipment. Structural overhangs and roof extensions are allowed.

Entrance and exit rules: 110.26(C)

• Every working space: at least one entrance big enough to get in and out. Open equipment doors can't block it.
• 1200 A or more and over 6 ft wide: an entrance at each end, at least 24 in. wide and 6½ ft high. Service disconnects with a combined 1200 A or more over 6 ft wide count too.
• One entrance is enough with a continuous, unobstructed exit path, or twice the Table 110.26(A)(1) depth.
• 800 A or more with overcurrent, switching or control devices: personnel doors within 25 ft must open in the direction of exit travel. They need listed panic or fire exit hardware.

Worked example: a commercial electrical room

An electrical room has block walls on each side of a 6 ft aisle.

1. 480Y/277 V panelboard, 20 in. wide, facing block: 277 V to ground, and block is grounded (Condition 2). Depth 3½ ft, width 30 in., height 6½ ft.
2. Its dedicated space: 20 in. wide by the panel's depth. Keep the HVAC duct out.
3. Second 480Y/277 V panelboard facing the first: Condition 3, so 4 ft. The 6 ft aisle passes.
4. 1600 A, 480Y/277 V switchboard, 8 ft wide: an entrance at each end, 24 in. by 6½ ft. Or one entrance with unobstructed egress or doubled depth (2 × 3½ ft = 7 ft).
5. Room door 15 ft away: it's within 25 ft of 800 A or more equipment. It must open in the direction of exit travel, with listed panic or fire exit hardware.

Common working space exam traps

• Using phase-to-phase voltage. A 480Y/277 V panel uses 277 V.
• Mixing up the two 6s. Working space height is 6½ ft from the floor. The dedicated space runs 6 ft above the equipment.
• Width equals panel width. The minimum is 30 in., even for a 14 in. panel.

These dimensions are from the 2020 NEC. If your state enforces a different edition, see NEC adoption by state or JCR's state requirements page.

Working space questions

How much clearance do you need in front of an electrical panel?

A typical 120/240 V home panel is 120 V to ground, so 3 ft of depth. The space must be at least 30 in. wide (or the panel width, if wider) and 6½ ft high. Doors must open at least 90 degrees.

What is the working space for a 480 volt panel?

A 480Y/277 V panel is 277 V to ground, so it uses the 151–600 V row. Depth is 3 ft for Condition 1, 3½ ft for Condition 2 and 4 ft for Condition 3.

Can anything be installed above an electrical panel?

Not in the dedicated space, which runs up to 6 ft above the panel or the structural ceiling, whichever is lower. Pipes and ducts stay out. Above it, foreign systems are OK if the panel is protected from leaks, condensation and breaks.

When does a working space need two entrances?

When equipment rated 1200 A or more is over 6 ft wide. Each entrance must be at least 24 in. wide and 6½ ft high. One entrance is allowed with unobstructed egress or doubled depth.

Does an existing house need 6½ ft of headroom for a new panel?

Not at 200 A or less. Exception No. 2 to 110.26(A)(3) lets that equipment sit under 6½ ft of headroom in an existing dwelling unit. It covers service equipment and panelboards. Depth and width rules still apply.

Related guides: 200 amp service wire size (Table 310.12) · Main bonding jumper size (250.28) · Dwelling service load calculation

More worked examples: all NEC Answers.