How to Work on a Roof That Carries Solar Panels

Why this matters

A solar array turns a roof into a place where something is energized every hour the sun is up, whatever anyone does at the breaker. Roofers, gutter crews, chimney sweeps and HVAC techs all end up on these roofs for work that has nothing to do with solar, and the damage they do is ordinary: a boot heel through a module's glass, a ladder resting on the conduit that runs down the wall, a gutter bracket screwed through a wire run under the eave. None of it is dramatic on the day. A cracked cell or a nicked conductor can become a hot spot or an arc weeks later. This card is the procedure for doing your own work around an array without touching it. How the system works is covered in Solar PV Basics for Trade Service Reference; this card is about where you put your hands, feet and ladder.

Safety first

• Smoke, a burning smell, crackling or visible arcing from the array, its wiring or any box on the wall: get off the roof by the ladder farthest from it, keep everyone back, and call 911. Tell them it is a solar system. Do not spray water on it, cover it, or open any box.
• A broken module or a cut wire: do not touch the module, its frame or the exposed conductors, and keep tools off them. Modules make voltage whenever light hits them; no switch on the house changes that.
• Fall protection is not relaxed by the array. Construction work on a residential roof triggers fall protection at 6 ft under 29 CFR 1926.501, and maintenance work that is not construction falls under 29 CFR 1910.28 at 4 ft. An array takes away walking surface and hides edges, so plan anchors and paths with it in mind.

The procedure

1. Identify the system before you set the ladder

Do it because the labels tell you what kind of system it is, who installed it and how to shut it down, and the ground is the only place you can read them safely.

Walk the house. Find the inverter (on a wall, in the garage, or none at all if the system uses microinverters under each module), the AC disconnect near the meter, a rapid shutdown switch if there is one, and the labels at the service equipment. NEC 690.56, as adopted by your jurisdiction, requires a rapid shutdown label at the service on systems that have it, and many installers add their own sticker with a phone number. Photograph every label. Note whether there is a battery, because a battery changes what stays live; see related: Home Battery Systems for the Trades That Share Their Wall.

What breaks if skipped: you are on the roof before you know whether the house has a shutdown switch, and the one decision that needs it happens up there.

2. Ask about rapid shutdown, and understand what it does not do

Do it because rapid shutdown is the only lever a non-solar trade can pull, and it is easy to believe it does more than it does.

Rapid shutdown arrived in the 2014 NEC at 690.12 and was tightened in the 2017 edition. Under the 2017 and later editions, as adopted, initiating it brings conductors more than 1 ft outside the array down to 30 V or less within 30 seconds. Inside the array boundary the limits depend on the edition and on the equipment, and the modules themselves still produce voltage in daylight. A system installed before your jurisdiction adopted the 2014 edition may have no rapid shutdown at all.

Ask the homeowner whether the system has a shutdown switch and whether they are comfortable with it being used. Initiating it is what it is designed for, but it also stops production and may log an event the owner's monitoring company sees, so it is their call. For most work near but not on the array, you do not need it at all. For anything that brings you within reach of array wiring, ask for it, and still treat the array as live.

What breaks if skipped: someone flips the switch, believes the roof is now dead, and leans on a module frame with a cracked back sheet.

3. Keep off modules, racking and conduit

Do it because none of them are walking surfaces, and the damage is invisible.

Modules are glass over cells that crack under point loads. A knee or a boot can microcrack cells with no visible mark, and those cracks grow into hot spots. Racking rails flex and their attachments are flashed into the roof; stepping on a rail can unseat a flashing and start a leak under the array. Conduit and junction boxes on the roof carry the array's output: DC, or AC on a microinverter system. Plan your path around the array, not across it. Do not use a module edge as a handhold, do not set tools or bundles of shingles on it, and do not lean a ladder or a toe board against it.

What breaks if skipped: a leak or a hot spot shows up months later, and the solar company's inspection finds a boot print.

4. Protect the wiring you cannot see

Do it because the conductors under an array run along the rails, through the gap between the modules and the roof, and often out to an edge, where they meet gutter, fascia and flashing work.

Before you cut, nail or screw anywhere near the array, look under its edges with a flashlight. Expect wire bundles clipped to the rails and a combiner or junction box at one end. Expect a conduit leaving the array to drop over the eave or rake and down the wall. Roofers working near the edge of an array keep nails and cutting blades out of the area under the module edge; gutter crews check the fascia line for conduit before setting hangers; chimney sweeps keep brushes, rods and debris from landing in the gap under the modules.

What breaks if skipped: a hanger screw or a nail through a conductor's insulation, which may not fault until rain gets to it.

5. Place ladders away from the conduit run

Do it because the conduit and its fittings dropping down the wall are the most common thing a ladder lands on near a solar home.

Find where the conduit leaves the roof and where it goes on the wall, then set your ladder at least a ladder's width away from it, on a part of the eave with no array above it if you can. Do not tie off to conduit, a disconnect, a rapid shutdown switch or an inverter. Keep ladder feet off any wire running along the ground to a ground-mounted array or a detached battery.

What breaks if skipped: a ladder crushes or pulls the conduit away from a fitting, opening a path for water into a live box.

6. Leave the array's work to the solar contractor

Do it because removing and reinstalling modules is solar work, and doing it without the training and the manufacturer's procedure risks the system, its warranty and the person handling it.

If your job needs the modules off (a reroof under the array, a chimney rebuild beside it, an HVAC curb under it), the homeowner engages the solar installer or another solar contractor for the removal and the reinstall, and your schedule is built around them. Your scope ends at the edge of the array until they hand the roof back.

7. If you damage something, stop and report it the same day

Do it because the damage you report is a repair; the damage you do not report is a fire risk with your name on it later.

Stop work in that area. Photograph the damage from where you stand without touching it. Tell the homeowner, give them the photos, and ask them to call the solar company, who can read the system's monitoring for a fault. Write it in your job record with the time and what happened. Do not cover a broken module with a metal tarp or tape a cut wire.

A worked example: gutters under an array

A gutter crew is replacing 58 ft of gutter across the back eave of a two-story house. An array of 14 modules sits on the back roof plane, two rows of 7, with its lower row ending about 3 ft above the eave.

Step 1, identify. On the ground the crew finds microinverters (a label at the AC disconnect says so, and there is no wall inverter), a rapid shutdown switch beside the meter, the installer's sticker with a phone number, and no battery. Photographs taken.

Step 2, ask. The homeowner says the switch is fine to use but would rather keep the system running. The crew's work is at the eave, more than 1 ft outside the array, and nothing in their scope touches array wiring, so they leave it on.

Step 4, the wiring. From the ladder at the far end, a flashlight under the lower row shows the trunk cable clipped to the rail, running to a junction box at the left end of the array. A gray conduit leaves the box, crosses 3 ft of shingles, drops over the eave about 9 ft from the left corner, and runs down the wall to the disconnect.

That conduit changes three things. The old gutter's hanger at 8 ft from the corner sits about 1 ft from the conduit where it crosses the fascia line. The new gutter's hangers go at 2 ft centers, so the crew lays them out to land at 8 ft and 10 ft, putting the conduit in the 2 ft gap between those two hangers rather than under a screw. And the downspout the crew planned at the left corner would run down the wall right beside the conduit's drop, so they move it to the right corner.

Step 5, ladders. For the left end, one ladder goes 3 ft from the left corner, which is 9 minus 3, 6 ft from the conduit. The span from 6 ft to 12 ft is worked from that ladder and from one set at 15 ft, 6 ft on the other side, so no ladder is ever set within 6 ft of the conduit. The rest of the eave is worked from the right half.

Step 3, keep off. The new gutter's back flange goes under the drip edge; nobody goes onto the roof plane at all. Old hangers are cut from below.

Result. 58 ft of gutter hung on 30 hangers (58 divided by 2 is 29 spaces, so 30 hangers including both ends), the downspout at the right corner, nothing touched within the array, the conduit undisturbed. The job record notes the conduit's position at 9 ft from the left corner for the next crew.

What would change the call

• The reroof is under the array: step 6 governs, and the removal is the solar contractor's. Your crew does not lift a module even to slide underlayment beneath it.
• The system has a battery: shutting down the array does not necessarily make the house's AC wiring dead, and the wall the battery sits on is another trade's equipment. See related: Homes with Solar, Batteries or Generators Already Installed.
• An HVAC unit on the roof next to the array: the service path to the unit is planned on the ground. If the only way to the unit crosses the array, the job is rescheduled with the solar contractor rather than stepped across. Under IRC R324.6, as adopted, many residential arrays must leave roof access pathways, commonly 36 in wide; where they exist, those pathways are your route.

How to know you got it right

At the end of the day, every label photo is in the job record, nobody stepped on or leaned against a module, rail, box or conduit, ladders were never set against the conduit run, and anything damaged was photographed, reported to the homeowner and written down.

References

• NFPA 70 (NEC), Sections 690.12 and 690.56, as adopted by your jurisdiction; check the edition
• IRC Section R324.6, roof access and pathways, as adopted; check the current edition
• 29 CFR 1926.501 (construction) and 29 CFR 1910.28 (general industry), fall protection
• See related: Solar PV Basics for Trade Service Reference
• See related: Solar Arrays for Every Trade: What Stays Live in Daylight