Working Clearance Verification Before Equipment Is Set

Purpose

Working clearance is cheap before the equipment is fastened and expensive afterwards. This SOP fixes the location against measured numbers taken in the FINISHED condition - drywall on, tile down, cabinet doors hung - so the panel is set once. It also catches the failure nobody expects, which is not the space in front of the panel but the space above it, where another trade's piping ends up because their drawing did not show yours.

Without this pass, the panel goes on the stud, the wall closes, a pantry door gets hung that swings into the space, and the correction is a panel relocation through finished work.

Scope

Panelboards, switchboards, service equipment, disconnects and control equipment set indoors or outdoors at dwellings and small commercial buildings, verified before the equipment is permanently fastened and again before energization.

Does not cover the emergency disconnect location decision that calls this SOP (emergency-disconnect-installation-on-a-service-replacement), the panel changeout itself (service-panel-upgrade), or the arc-flash boundary, which is a separate space with a different basis (arc-flash-boundary-and-ppe-selection-before-panel-work).

Roles and responsibilities

Procedure

1. Establish the two properties that set the numbers before you measure anything. The depth requirement is set by nominal voltage to ground and by the condition of the space, and Table 110.26(A)(1) reads on both. At 0 to 150 V to ground, which covers ordinary residential 120/240 V equipment, the depth is 3 ft under all three conditions. Above that band the conditions separate: Condition 1 is exposed live parts on one side with nothing live or grounded opposite, Condition 2 has grounded parts opposite, Condition 3 has exposed live parts on both sides. Acceptance: voltage to ground and condition number both written on the sheet, with the table depth read from that row. Wrong looks like a 3 ft figure carried onto a 480 V panel with grounded parts opposite, where the row gives more. Stop rule: no voltage and condition on the sheet, no measurement. Hazard: none at this step, it is read from a table.

2. Pull the finished dimensions from the drawings, not the framing you are standing in. Get wall finish thickness on both sides, floor build-up, ceiling height at the equipment, cabinet depth and every door swing that reaches the space. Acceptance: each finish thickness written as a number in inches with its source, and any unknown flagged to the general contractor in writing. Wrong looks like a rough-framing measurement recorded as the answer, which is always generous by the thickness of everything not yet installed. Stop rule: an unknown finish thickness stops the sign-off; the panel can be roughed but not signed off. Hazard: none at this step, it is a drawing review.

3. Measure depth from the equipment face to the nearest finished obstruction, and print the correction. Take the rough measurement, subtract each finish thickness that will be added in that path, and record the finished result. Acceptance: rough measurement, each subtraction, and the finished depth all written as separate numbers, with the finished depth at or above the table value from step 1. Wrong looks like a single number on the sheet with nothing showing how it was arrived at. Stop rule: finished depth below the table value means the equipment moves, and it moves before it is fastened. Hazard: working in an active construction area - confirm any temporary power feeding the space is on a ground-fault protected assured-grounding arrangement before running a tape near open conductors, and treat every cut-back cable end as live.

4. Measure width and swing the door through 90 degrees. The width is 30 in or the width of the equipment, whichever is greater, centred on the equipment or shifted as the section permits, and the equipment door has to open at least 90 degrees. Acceptance: finished width recorded and at or above the requirement, plus a stated yes on the door reaching 90 degrees against the finished condition, including any adjacent cabinet or door that will exist later. Wrong looks like a width measured with the panel door removed. Stop rule: a door that cannot reach 90 degrees in the finished condition is a location failure, not a trim detail. Hazard: none at this step.

5. Measure headroom from finished floor to the lowest obstruction over the space. The requirement is 6.5 ft or the height of the equipment, whichever is greater. Acceptance: finished floor level established, headroom measured and recorded, at or above the requirement, with any soffit, duct or beam over the space identified. Wrong looks like headroom measured to a joist bottom in a basement where a dropped ceiling is coming. Stop rule: short headroom moves the equipment or removes the obstruction, decided before fastening. Hazard: none at this step.

6. Check the dedicated equipment space above the equipment, and name what is in it. For indoor equipment the adopted 110.26(E) reserves the space above the equipment footprint, extending to 6 ft above the equipment or to the structural ceiling, whichever is lower, for the electrical installation - no piping, ducts or equipment foreign to it. Acceptance: the zone height computed and written, and a stated list of what crosses it, which should be nothing foreign. Wrong looks like a condensate line, a gas pipe or a duct crossing the zone and nobody treating it as a defect because it is not in front of the panel. Stop rule: anything foreign in the zone gets moved by the trade that owns it, in writing, before the equipment is fastened. Hazard: none at this step, it is observation and arithmetic.

7. Check the prohibitions and the access requirements that are not dimensions. Overcurrent devices are not permitted in dwelling-unit bathrooms or in clothes closets and not over steps, per the adopted 240.24; service disconnects have to be readily accessible per 230.70; and 110.26 requires illumination for the working space at indoor service equipment and panelboards. Acceptance: each of those answered yes or no on the sheet with its section. Wrong looks like a panel in a walk-in closet that measures beautifully and is prohibited outright. Stop rule: a prohibited location is a relocation, and no measurement rescues it. Hazard: none at this step.

8. Mark the footprint, photograph it, and re-verify before energization. Mark the approved equipment footprint and the dedicated zone on the framing so other trades can see it, photograph it with a tape in frame, then re-run steps 3 through 6 after finishes are installed and before the equipment is energized. Acceptance: a second set of finished measurements recorded on the same sheet, each still at or above its requirement. Wrong looks like a sign-off from the rough that nobody revisited after the tile went down. Stop rule: any measurement that moved below its requirement between rough and finish stops energization until it is corrected. Hazard: the re-verify happens on installed equipment that may already be fed - if the service is live, do not open covers to measure; measure to the closed enclosure face and set boundary and PPE under arc-flash-boundary-and-ppe-selection-before-panel-work before anything is opened.

When the site does not match the assumption

Another trade refuses to move a pipe in the dedicated space. It goes in writing to the general contractor the same day with the section cited and the photograph attached, and this shop does not fasten equipment under it. A verbal agreement to move it later is worth nothing at final inspection.

The equipment is rated above the 0 to 150 V band. Go back to step 1 and read the correct table row; the condition number now changes the depth, and a space that passed at 3 ft may not pass at the wider figure.

The equipment is outdoors. The dimensions still apply and the obstruction list changes: fences, meters, gas equipment, landscaping at maturity and a gate swinging into the space all count.

The record this produces

One clearance sheet per equipment location: voltage to ground, condition number and the table depth from step 1; each finish thickness with its source from step 2; rough depth, each subtraction and finished depth from step 3; finished width plus the 90-degree door answer from step 4; finished headroom from step 5; the dedicated zone height and its contents from step 6; the four prohibition and access answers from step 7; and the second set of finished measurements plus the footprint photograph from step 8.

The inspector reads the finished numbers. The next shop at this panel reads the sheet to learn whether the space was ever compliant or just accepted.

Worked pass: basement panel relocation in a finished-basement remodel, 120/240 V service

Step 1 records 120 V to ground and Condition 2, since a metal-jacketed water heater will stand opposite. At 0 to 150 V the table gives 3 ft, or 36 in, under all three conditions, so the condition does not change the number here - it would above that band. Step 2 collects finish thicknesses from the drawings: 0.5 in drywall on the opposite wall, 1.5 in of planned tile and backer over it, and 1.25 in of floor build-up.

Step 3: rough depth to the opposite framing measures 41 in. Subtract 0.5 in of drywall and 1.5 in of tile and backer, so 41 minus 2.0 leaves 39 in finished, against 36 in required, a 3 in margin. Step 4: the panel is 14.5 in wide so the requirement is the 30 in minimum; rough width between the chase and the corner is 34 in, less 0.5 in of drywall each side, giving 33 in finished, a 3 in margin, and the 14 in panel door swings well past 90 degrees inside it. Step 5: rough ceiling at 96 in less the 1.25 in floor build-up gives 94.75 in of finished headroom against the 78 in required.

Step 6 fails. The panel top will sit 74 in above finished floor. The dedicated zone runs to 6 ft above the equipment or to the structural ceiling, whichever is lower; 74 plus 72 is 146 in, and the structural ceiling is at 94.75 in, so the ceiling governs and the zone is 94.75 minus 74, or 20.75 in above the panel. A 2 in condensate line crosses 14 in above the panel top, inside that 20.75 in zone. The stop rule fires: the line is foreign to the electrical installation, the finding goes to the general contractor in writing with the photograph, and the mechanical contractor reroutes it clear of the footprint before the panel is fastened. The re-check finds nothing foreign in the zone.

Step 7 answers all four: not a bathroom, not a clothes closet, not over steps, service disconnect readily accessible, and a light fixture is added over the space. Step 8 marks the footprint and the zone on the framing, photographs it with a tape in frame, and the post-finish re-verify returns 39 in, 33 in and 94.75 in unchanged. One failed step, caught at rough, resolved by the trade that caused it.

References

• NFPA 70, National Electrical Code, 110.26 including Table 110.26(A)(1) and the dedicated equipment space provisions, with 240.24 and 230.70, in the edition your authority having jurisdiction has adopted, which binds the installation and reaches you through the permit.
• NFPA 70E-2021, for approach boundaries and PPE selection, in the edition your employer's electrical safety program has adopted; these are separate from the working space in 110.26 and neither substitutes for the other.
• 29 CFR 1910.303(g)(1) for the general-industry working-space requirement around energized equipment.
• See related: emergency-disconnect-installation-on-a-service-replacement, service-panel-upgrade, arc-flash-boundary-and-ppe-selection-before-panel-work.