Electrical Working Clearance Checker

Five things, separately, for each piece of equipment you enter. The clear depth in front of the enclosure, against a minimum of 36 inches. The clear width across the front, against 30 inches or the equipment width, whichever is greater. The headroom at the equipment front, against 78 inches or the equipment height, whichever is greater. Whether doors and hinged covers can open to at least 90 degrees. And, for panelboards, whether the space directly above the footprint is clear of pipes, ducts and other systems foreign to the electrical installation. They are reported line by line because a location can satisfy four of them and fail the fifth, and the fifth is the one that fails the inspection.

Because the requirement is the greater of two figures rather than a fixed number: at least 30 inches, or the width of the equipment where the equipment is wider than that. A 40-inch-wide enclosure needs 40 inches of clear width, not 30. This is the input people most often leave out, and leaving it out is why a location can be measured carefully and still be wrong. The same shape applies to headroom, which is 78 inches or the equipment height, whichever is greater. Enter the enclosure dimensions and the tool computes the requirement instead of you having to remember which rule applies.

No. The full width has to be clear somewhere across the equipment front, but it does not have to be symmetrical about the enclosure. That helps in tight equipment runs and it is frequently forgotten in both directions — people either assume it must be centred and reject a workable location, or measure only the space directly in front of the enclosure and miss that the required width is not available anywhere. Measure the clear width you actually have across the front and enter that.

Because it is an independent failure mode and it is the one least visible on a drawing. Equipment sited near a corner, a projecting wall, a downpipe or an adjacent enclosure can satisfy depth, width and headroom and still fail because the cover fouls something at seventy degrees. Nothing about the three dimensional measurements predicts it. It is checked by opening the cover, or on a drawing by swinging the door in plan, and it is worth doing before the equipment is mounted rather than after.

It is a separate requirement from the working space in front, and it is the one people miss because they are looking in the wrong direction. The space directly above the equipment footprint, from the top of the equipment upward, has to be kept clear of building systems foreign to the electrical installation — water pipes, drainage, condensate lines, ducts and unrelated equipment. A panel can have a clear three feet in front of it and fail because a heating duct or a condensate drain crosses above it. On a retrofit that finding is awkward, because the offending pipe usually predates the work by decades and relocating it is a plumbing or HVAC job rather than an electrical one.

No, and the tool asks about them separately for that reason. They are two requirements assessed independently. A disconnect can be perfectly readily accessible — reachable quickly, without a ladder, without moving obstacles — and still lack the clear working space required in front of it. It can also have ample working space and fail on access, for instance behind a locked gate or established planting. A compliant installation satisfies both, and an inspector will look at both.

No. It is a preparation aid that performs arithmetic on measurements you take. The thresholds it compares against are the ones that apply across the conditions at residential PV voltages; the table in the code is conditional, depth can increase at higher voltages and can depend on what sits on the opposite side of the working space, and the edition your jurisdiction has adopted is the one that governs. It makes no determination about conductors, overcurrent protection or equipment listing. The design belongs to the licensed electrical contractor and the engineer of record, and the permitted scope belongs to the plan set the jurisdiction reviews.