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The width of the electrical equipment (panel, switchboard, etc.) requiring working clearance in front of it.
The equipment's own width. It matters because the required clear width is the GREATER of this and a fixed minimum, so a narrow panel does not get a narrow working space — a single-width board still needs the full minimum in front of it, and a wide switchboard needs its own width. The space must also stay clear for the full height of the equipment, which is what rules out storing anything against the wall beside it.
The minimum clear depth required in front of the equipment, from NEC Table 110.26(A)(1) based on nominal voltage-to-ground and installation condition.
Two things pick this row, and the second is the one that gets skipped: the voltage to ground, and the CONDITION — what is on the other side of the working space. Exposed live parts facing an insulated wall is one condition; the same equipment facing another live panel across the aisle is the worst, and needs materially more room. Read the condition off the room as built rather than off the drawing, because a panel added opposite later changes it.
Required minimum working clearance area
7.38 sq ft
Required depth depends on the equipment's nominal voltage-to-ground and the installation condition (1/2/3, based on what's opposite the equipment) per NEC Table 110.26(A)(1) — look up the correct depth for your specific installation rather than assuming a default. The width floor is stated by NEC 110.26(A)(2) as 750mm (30in) — two code figures, not a conversion of one another, since 30in is 762mm; the area here is worked from the 750mm figure, so if you are building to the imperial column allow the full 30in of width. Height clearance (2.0m/6.5ft minimum) is a separate NEC 110.26(E) requirement not covered by this floor-area calculation.
- Clear width used (NEC 110.26(A)(2) floor: 750 mm / 30 in)
- 30 in
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Electrical Equipment Working Clearance Space Calculator: 7.38 sq ft — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- NEC 110.26(A) requires a minimum clear working space in front of electrical equipment, with depth determined by voltage-to-ground and condition (typically 900 mm/3 ft, 1.07 m/3.5 ft, or 1.22 m/4 ft, which are the table's own paired figures rather than conversions of each other), and width the greater of the equipment width or 750mm/2.5ft
Inputs used
- Equipment Width
- 2 ft
- Required Clearance Depth (Per NEC 110.26(A) Table — 900 mm/1.07 m/1.22 m or 3/3.5/4 ft by Voltage & Condition)
- 3 ft
Intermediate steps
- Clear width used (NEC 110.26(A)(2) floor: 750 mm / 30 in)
- 30 in
Confidence note: Required depth depends on the equipment's nominal voltage-to-ground and the installation condition (1/2/3, based on what's opposite the equipment) per NEC Table 110.26(A)(1) — look up the correct depth for your specific installation rather than assuming a default. The width floor is stated by NEC 110.26(A)(2) as 750mm (30in) — two code figures, not a conversion of one another, since 30in is 762mm; the area here is worked from the 750mm figure, so if you are building to the imperial column allow the full 30in of width. Height clearance (2.0m/6.5ft minimum) is a separate NEC 110.26(E) requirement not covered by this floor-area calculation.
What this calculation does not cover
- Gives a floor area, not the volume that has to stay clear. Above a switchboard or panelboard, NEC 110.26(E) keeps that same footprint dedicated to electrical use up to 1.8 m (6 ft) above the equipment or to the structural ceiling — no piping, no ducts, nothing foreign to the installation. A duct routed over the panel fails the room after the clearance in front of it was got right.
- Ignores what swings into the space. NEC 110.26(A)(2) requires the width to allow equipment doors and hinged panels to open at least 90 degrees, and a room door that swings back across the working space eats it. This is a clear floor area, not a strip that people, doors and storage may share.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- NEC 110.26(A) requires a minimum clear working space in front of electrical equipment, with depth determined by voltage-to-ground and condition (typically 900 mm/3 ft, 1.07 m/3.5 ft, or 1.22 m/4 ft, which are the table's own paired figures rather than conversions of each other), and width the greater of the equipment width or 750mm/2.5ft
Which documents these citations point at
- National Electrical Code (NFPA 70) — 110.26(A) (United States)Electrical installations — conductor sizing and protection, load calculation, wiring methods, grounding and working clearances.
A code or standard has force only where a jurisdiction has adopted it, usually with local amendments. This site holds no adoption data for any authority, so check what is in force with the authority where you build. Any section cited above without an edition should be checked against the edition in force where you build. What it would take to know.
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Your workspace
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Protection this work requires
- Stop and check first. Textured ceiling coatings, board behind panels, floor tiles and bitumen adhesive in older buildings — built before asbestos was banned or phased out where you are — can contain asbestos, and drilling or sanding them releases fibres. Do not disturb it — have it sampled first. This is not a job for better PPE.
Tools and safety for this job
To first-fix electrical. Generic types, no brands, no prices.
- Assume every cable is live until proved dead at the point you will touch, with a two-pole tester you have just proved on a known source.
First-fix electrical: This site does not publish a tool list for electrical installation work. In every market it serves, fixed wiring is either reserved to a registered electrician or notifiable to a building authority, and the failure mode is a fire or an electrocution months later rather than a visibly bad job on the day. The calculator gives you the quantities to discuss and to buy against. The installation is a job for a qualified electrician, and the certificate they issue is the point of them.