Working-Space Clearance Lookup (NEC 110.26)
Returns the NEC 110.26(A) working space in front of electrical equipment.
Example
You enter
- Nominal voltage to ground 151-600 V
- Condition (what is opposite the live parts) 2
- Equipment width (in) 24
You get
- Working depth (ft) 3.5
- Working width (in) 30
- Headroom (ft) 6.5
Checked against published worked examples from: NEC 2023 (NFPA 70).
Details, formula, and sources
ScopeThe depth by voltage-to-ground and Condition 1/2/3 (0-150 V is 3 ft; 151-600 V is 3 / 3.5 / 4 ft), the width as the greater of 30 in or the equipment width, and 6.5 ft of headroom with a required 90-degree door swing. 110.26(E) adds the dedicated equipment space. A reference lookup; the AHJ governs.
Formula or tabledepth from Table 110.26(A)(1) by nominal voltage to ground and Condition 1/2/3 (0-150 V: 3/3/3 ft; 151-600 V: 3/3.5/4 ft; 601-1000 V: 3/4/5 ft); width = max(30 in, equipment width); headroom = 6.5 ft, with a 90-degree door swing.
Source and editionWorking space about electrical equipment, NEC 2023 110.26(A), and dedicated equipment space 110.26(E), by name.
Free accessNEC is free to read at nfpa.org/freeaccess. Condition 1/2/3 describe what is across from the live parts; the width is the greater of 30 in or the equipment width.
What governsEstimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
API field namesnominal_v_to_ground, condition, equipment_width_in, depth_ft, width_in, height_ft
- Depth table 0-150 V to ground is 3 ft for all conditions; 151-600 V is 3 / 3.5 / 4 ft and 601-1000 V is 3 / 4 / 5 ft for Conditions 1 / 2 / 3NEC Table 110.26(A)(1)
- Width and headroom width is the greater of 30 in or the equipment width; headroom 6.5 ft or equipment height; a 90-degree door swing is requiredNEC 110.26(A)(2),(3)