How Much Working Clearance Solar Equipment Needs (NEC 110.26)
By Seamless Home Team, Solar fulfillment operations · September 2, 2026
Quick answer
Electrical equipment that may need examination or servicing while energised has to have a defined clear working space in front of it, and PV solar inverters, disconnects and combiner panels are all in that category. The essentials are a minimum depth of three feet measured from the exposed live parts or the enclosure front for the voltages used in residential PV work, a minimum width of thirty inches or the width of the equipment, whichever is greater, with equipment doors able to open to at least ninety degrees, and headroom of six and a half feet or the height of the equipment, whichever is greater. The space has to be clear and cannot be used for storage, it has to be illuminated where it is indoors, and panelboards carry an additional dedicated space above them that other building services such as pipes and ducts must not occupy. The practical point is that these are siting constraints rather than wiring rules: the failures are almost always about where the equipment was mounted relative to a water heater, a gas meter, a garage shelf or a low ceiling, which makes working clearance something to resolve at the site survey rather than on the day of inspection.
An inverter can be correctly sized, correctly wired, correctly labelled, and still fail its inspection because of what is standing in front of it.
Working clearance is one of the few PV solar compliance requirements that has nothing to do with the electrical design. It is a rule about space. And because it is a rule about space, it is decided at the site survey and settled in the drawings long before a crew arrives, which is exactly why it fails: nobody owns it, so it becomes a field decision made by whoever is holding the drill.
The four dimensions
NEC 110.26 requires clear working space around electrical equipment that may need examination, adjustment, servicing or maintenance while energised. On a PV solar installation that covers the inverter, the AC and DC disconnecting means, combiner panels, the service panel being connected to, and energy storage equipment.
| Dimension | Requirement for residential PV voltages | Measured from |
|---|---|---|
| Depth | At least 3 feet | The enclosure front, or exposed live parts, outward |
| Width | At least 30 inches, or the equipment width if wider | Across the equipment front |
| Headroom | At least 6.5 feet, or the equipment height if greater | Floor or standing surface to the obstruction above |
| Door swing | Doors and hinged covers open to at least 90° | Within the working space |
Three points about reading that table.
The width does not have to be centred on the equipment, but the full 30 inches has to be clear somewhere across the front. This helps in tight equipment runs and is frequently forgotten.
The door swing is a real constraint, not a footnote. Equipment sited close to 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.
Depth increases at higher voltages than residential PV normally involves, and it can depend on what sits on the opposite side of the working space. The three-foot figure is the one that applies across the conditions at residential PV voltages, but the table in the code is conditional, and the edition your jurisdiction has adopted is the one that governs.
The space above: a separate requirement
Dedicated equipment space is the requirement people miss because they are looking in the wrong direction.
For panelboards and similar equipment, the space directly above the equipment footprint — from the top of the equipment upward to a defined height or the structural ceiling — has to be kept clear of building systems foreign to the electrical installation. Water pipes, drainage, condensate lines, ducts and unrelated equipment are not permitted in it. The reasoning is twofold: a leak above live equipment is an obvious hazard, and an obstruction there makes future work on the panel harder than it should be.
This is assessed independently of the working space in front. A panel can have a clear three feet in front of it and fail because a heating duct or a condensate drain crosses the space above it.
On a retrofit that finding is genuinely awkward, because the offending pipe or duct usually predates the PV work by decades and relocating it is a plumbing or HVAC job rather than an electrical one. It is a good example of why the condition of the existing service equipment and what surrounds it belongs in the site survey record rather than being discovered by an inspector. It sits alongside the other ways an existing panel constrains a PV project, whether that is the 120% busbar calculation or a panel nobody will work on at all.
The five ways it actually fails
Clearance failures reduce, almost without exception, to a siting decision:
- Something occupies the space. A water heater, furnace, softener, gas meter or stored household items in front of the equipment. The most common cause by a wide margin.
- Not enough headroom. Equipment under a stair, in a low crawl space, beneath a soffit, or under a sloping ceiling where 6.5 feet is not available at the equipment front.
- The door cannot open. Ninety degrees is not achievable because of a corner, a projection or an adjacent enclosure.
- The dedicated space above a panelboard is occupied by a pipe or duct.
- Accessibility is compromised. Equipment behind a locked gate, a fence panel or established planting, which raises both clearance and access.
None of these is a wiring defect. None is a workmanship defect. All five were decidable before anybody arrived on site with equipment, which is the entire argument for treating equipment siting as an output of the survey and the design rather than a judgement made at the wall.
Outdoors changes the failure modes, not the rule
The requirement is not relaxed outdoors. Equipment must be in enclosures suitable for the conditions, and the depth, width, headroom and door swing all still apply. Illumination is required for indoor working spaces rather than outdoor ones, but that is the only meaningful difference.
What changes is how it fails. Outdoor clearance problems tend to be:
- The clear space falls across a slope, a step, a window well or a drainage channel, so it exists on the drawing but there is nowhere to stand.
- Equipment sits behind a fence panel, a locked side gate, or planting that was small at install and is not any more.
- The door fouls a wall return, a downpipe or the utility meter box.
Outdoor siting also determines whether the required markings are legible where they are, since a placard can end up facing a wall or crossed by conduit in a tight run. That makes it worth resolving equipment layout and the label schedule together rather than sequentially.
Where the decision belongs
Working clearance is the clearest case on a PV solar project of a requirement that is cheap at design, moderate at survey, expensive in the field, and worst at inspection.
At design and plan review, a clearance problem costs a redrawn sheet. A reviewer who queries an inverter location has saved you a site visit, and clearance is among the things a plan reviewer can catch from the drawings, which is why it belongs in the reasons applications get rejected rather than in the reasons installations fail.
At survey, it costs a measurement and a photograph. The survey has to record not just the service panel but what is in front of it and above it, and what the homeowner is currently using that wall and floor for.
In the field, a crew that arrives to find the drawn location unusable has only bad options: install as drawn and fail, or improvise a location that never went through plan review and may not match the submitted drawings, which can itself amount to a design change needing a new permit.
At inspection, it costs a correction notice, a return visit, a re-inspection in the queue, and the downstream delay to everything that waits on the inspection sign-off.
Because the cost lands so far from where the omission occurred, the responsibility for re-siting after a clearance failure is worth allocating in the subcontract in advance. It is rarely a workmanship failure, so defaulting it to the installing crew is both unfair and, in the medium term, a way of losing good crews.
One thing to tell the homeowner
There is a compliance problem here that no contractor can solve, and it is worth naming at handover.
The working space in front of the equipment has to stay clear, and after handover the only person in a position to keep it clear is the homeowner. Boxes get stacked, bicycles get leaned, shelving gets installed, a car gets parked closer. A compliant installation becomes non-compliant and nobody is there to see it, until a technician arrives for a service call and cannot safely work on live equipment.
Saying so plainly at handover, and explaining that the space exists so somebody can work safely in an emergency rather than to satisfy an inspector, is more effective than a label. It also avoids the awkward version of the conversation later, when a service visit turns into a request to clear a garage.
The bottom line
Working clearance is three feet of depth, thirty inches of width or the equipment width, six and a half feet of headroom, and a door that opens ninety degrees, for every piece of PV solar equipment that might be worked on live. Panelboards additionally need the space above them kept free of pipes and ducts, assessed separately. Outdoors the rule is the same and the failure modes differ.
Every one of the common failures is a siting decision that was available at survey and design. The cheapest place to catch a clearance problem is a drawing; the most expensive is an inspection queue. If a system is already built and you are deciding whether to call the inspection, score clearance alongside labels, DC-side protection and built-as-permitted before booking the visit — what happens at a solar final inspection sets out what the inspector will actually look at.
Seamless Home records equipment siting and clearances at survey and resolves them in the plan set as part of design and permitting, so the location a crew arrives to install is one that has already been checked against what is actually on the wall. Coverage is confirmed per service area rather than promised as blanket availability. If clearance corrections are recurring across your projects, get in touch and we can look at whether they are originating at survey or at design.
Frequently asked questions
How much clearance does a solar inverter need?
For the voltages used in residential PV solar work, the requirement is a clear working space at least three feet deep in front of the equipment, at least thirty inches wide or as wide as the equipment if the equipment is wider, and with at least six and a half feet of headroom or the height of the equipment if that is greater. The depth is measured from the enclosure front, or from the exposed live parts where they are exposed, outward into the room or the space in front of it. The width is measured across the equipment front and the thirty inches does not have to be centred on the equipment, but the whole of it must be clear. Equipment doors and hinged panels have to be able to open to at least ninety degrees within that space, which is a constraint people miss when siting equipment close to a corner or a projection. Deeper working space is required at higher voltages than residential PV normally involves, and the depth can also depend on what is on the opposite side of the space, so confirm the specific figures against the code edition your jurisdiction has adopted.
Does working clearance apply to disconnects as well as inverters?
Yes. The requirement attaches to electrical equipment likely to require examination, adjustment, servicing or maintenance while energised, and that description covers a good deal of a PV solar installation rather than just the inverter. AC and DC disconnecting means, combiner panels, the service panel the system connects to, rapid shutdown initiation equipment and energy storage equipment are all in scope. This is worth stating explicitly because the inverter usually gets the attention during design while the disconnects get positioned wherever the conduit run happens to make convenient, and a disconnect mounted above a gas meter or tucked behind a downpipe is a genuine and common correction. There is a related but separate requirement that certain disconnecting means be readily accessible, which is not the same thing as having working space: a switch can be readily accessible and still lack the clear space the code requires in front of it, and it can have ample space and still not be readily accessible.
Can I mount an inverter in a garage next to storage?
You can mount it in a garage, and this is entirely normal, but the working space in front of it must be kept clear and cannot be used for storage. That is a code requirement rather than a matter of tidiness, and it creates a practical difficulty nobody controls after handover: a homeowner who stacks boxes, leans bicycles or parks a car in the working space has made a compliant installation non-compliant, and neither the installer nor the inspector is there to see it. Two things follow. At design, avoid siting equipment where the working space is obviously going to be contested, such as the back wall of a single garage or the only wall a homeowner has for shelving, even where it technically complies on the day. At handover, tell the homeowner in plain terms that the marked-out space in front of the equipment has to stay empty and why, because the requirement exists so that somebody can work safely on live equipment in an emergency rather than for the inspector's benefit.
What is dedicated equipment space and how is it different?
It is a separate requirement, and it is about what is above the equipment rather than in front of it. For panelboards and similar equipment, the code requires the space directly above the equipment footprint, extending from the top of the equipment up to a defined height or to the structural ceiling, to be kept free of building systems that have nothing to do with the electrical installation. Water pipes, drainage, ducts, and equipment foreign to the electrical installation are not allowed to occupy it, the concern being both leakage onto live equipment and the obstruction of future work. Working space in front and dedicated space above are commonly confused and are assessed separately, so a panel can have a perfectly clear three feet in front of it and still fail because a condensate line or a heating duct was run through the space above it. On a retrofit this is one of the more awkward findings, because the offending pipe or duct usually predates the PV work by decades and moving it is not a small job.
Why did my solar installation fail on working clearance?
In practice, for one of five siting reasons. Equipment mounted too close to something that occupies the working space: a water heater, a furnace, a softener, a gas meter or a stored item. Insufficient headroom, most often equipment fitted under a stair, in a low crawl space, or beneath a soffit or a sloping ceiling. A door or hinged cover that cannot open ninety degrees because the equipment sits too near a corner, a projection or another enclosure. The dedicated space above a panelboard occupied by a pipe or a duct. Or equipment installed behind a locked gate, a fence panel or dense planting, which raises accessibility as well as clearance. What all five have in common is that they are consequences of where the equipment was put, not of how it was wired, which means they were all decidable before anyone arrived to install anything. That is the argument for treating equipment siting as a survey output rather than a field decision.
Does working clearance apply to outdoor solar equipment?
Yes, and the working space requirement is not relaxed by being outside. Outdoor equipment must be in enclosures suitable for the conditions and the required working space still has to exist in front of it. Outdoors this tends to fail in different ways from indoors: equipment sited where the clear space falls across a slope, a step, a window well or a drainage channel, so the space exists on the drawing but nobody can stand in it; equipment behind a fence panel, a locked side gate or established planting; and equipment positioned so that the door cannot open fully because of a wall return, a downpipe or a meter box. Illumination is required where the space is indoors rather than for outdoor equipment, but the depth, width and headroom apply in both cases. Outdoor siting also raises the placement of markings, because a placard that is legible on the bench can end up facing a wall or crossed by conduit in a tight equipment run.
Who is responsible for working clearance on a subcontracted install?
The licensed contractor whose permit the work sits under carries the code obligation, whoever chose the mounting position. The more useful question is where the decision was actually made, because working clearance is determined by the design and the survey rather than by the installing crew. A crew arriving with a plan set that shows an inverter on a wall which turns out to have a water heater in front of it has two options, both bad: install as drawn and fail inspection, or improvise a new location that has not been through plan review and may not match the submitted drawings. Neither is a workmanship failure. That makes equipment siting and the clearances around it something the survey has to record and the design has to resolve, and it makes the responsibility for a re-siting after a failed inspection worth allocating in the subcontract in advance, since the cost falls somewhere between design, survey and installation depending on where the omission originated.