Solar Permit to Work (PTW): 7-Step Process and Form

On a solar site the array stays live whenever light hits it, so opening a switch at the inverter does not make the work area safe. A permit to work (PTW) is how a crew proves it isolated, locked and tested before anyone touches a part.

Last updated: November 2026

A PTW makes the crew and the supervisor agree, in writing, on what is isolated, what is still live and who is in charge. This guide covers when a solar site needs one and the 7-step process. It also covers PV isolation, work at height, which rules apply, and how to keep paperwork useful. LOTO (lockout-tagout) means locking and tagging the switches that could power the work area.

A PTW is not a building permit. The two are covered below.

When Does a Solar Site Need a Permit to Work?

Issue a PTW when the task puts someone near a serious hazard. On solar sites that usually means:

• Live electrical parts, such as strings, combiner boxes and inverters.
• Stored energy, such as inverter capacitors and batteries.
• Work at height, such as roof mounting and roof cleaning.
• Confined spaces, such as some battery rooms and cable vaults.
• Hot work, such as grinding or welding near roofing material or racking.

A routine look from a safe place, with no contact, may need only a written risk assessment. Your safety adviser sets the rule for your company.

The law in each country sets duties, such as how to isolate electrical equipment and how to protect people at height. A PTW is a way to show those duties were met. The tables below show the main rules.

PTW vs Building Permit

The authority having jurisdiction (AHJ) is the local office that approves construction. It issues the building and electrical permit before you install. That permit decides whether you may build. A PTW decides how a crew does a hazardous task safely on site. You need both, and one never replaces the other.

Some building permit review is done by hand. In US places that use SolarAPP+, installers enter the system design and the tool checks each data point against code. If the design complies, the permit is issued at once. The SolarAPP+ site says it covers residential solar and energy storage, and that it frees staff from reviewing standard permits. Its help article lists an installer fee of USD 35 for a solar permit (updated 6 July 2026). Sources: SolarAPP+ and SolarAPP+ installer cost. For the permit side, see the solar permitting workflow and the solar permit package checklist.

Three Permit Types for Solar Work

Some companies use one form with tick boxes. Others use a separate form for each hazard. Both can work. A form that is too long will not be used.

The Solar PTW Process in 7 Steps

Role names differ by company. Here the issuer writes and approves the permit, the acceptor leads the crew, and the isolating person applies the locks.

1. Define the task and the hazards. Write down exactly what will be done, on which asset, and what can go wrong. “Replace inverter 3 at Site B” is a task. “Check the system” is not. Reject vague scopes.

2. Isolate and lock out. Switch off and disconnect every energy source that feeds the work point. Put a lock and a tag on each disconnect. The next section covers PV isolation.

3. Test before you touch. A qualified person checks, with a test meter, that the parts are dead. The meter must suit the voltage. Test for stray voltage and backfeed, not just the main supply.

4. Issue the permit and brief the crew. The issuer goes through the permit with the acceptor on site. It lists the isolation points, the parts that stay live, the protective gear and the emergency plan. The acceptor briefs the crew. Everyone signs.

5. Do the work inside the permit. Stop and reassess if the task, the weather or the hazards change.

6. Hand back. The acceptor confirms that tools and people are clear and that guards are back in place. Locks come off only as the rules allow.

7. Close out the records. Attach the test results and notes to the closed permit. File them where the asset’s records are kept.

A PTW is only as good as step 3. If crews skip the test, you have paperwork, not protection.

PTW Template: What to Put on a One-Page Form

Keep the form to one page. Put detail in the method statement, not on the permit.

PTW Isolation for Solar PV: AC, DC and Test

PV breaks one habit from other electrical work. You cannot switch off the source. Modules make power whenever light hits them. Opening a switch at the inverter does not make the wires in the array dead. Plan for a DC side that stays live and control it.

OSHA’s rule for work on electrical equipment sets a clear order for fixed equipment. Follow the same order on a PV site:

1. Decide the safe procedure first. Do this before you switch anything off.
2. Disconnect from every energy source. On a PV site that means the AC disconnect and the inverter AC breaker. It also means the inverter DC switch and the string fuses or isolators for the strings you will touch. Name each string in the permit. Strings in the same combiner may stay live.
3. Release stored energy. The rule says capacitors must be discharged. Wait the time your inverter manual gives. Treat batteries as a separate energy source.
4. Lock and tag each disconnect. One lock and one tag on each disconnecting means.
5. Test. A qualified person tests the work point with a meter. The test must also check for stray voltage and backfeed, even where the circuit is believed dead.

Source: 29 CFR 1910.333(b)(2), the OSHA rule for lockout and tagging of electrical equipment in general industry. The rule requires the meter to be checked just before and just after a test on circuits over 600 volts. Check the meter on every test as good practice. For the hardware, see the solar DC isolator guide. For the testing sequence, see the solar system commissioning protocol and the lockout-tagout glossary entry.

Two PV traps deserve a line on every electrical permit:

• Backfeed from other inverters. On a site with several inverters, switching off one inverter does not clear the AC board. List every source that can power your work point.
• Module-level electronics. Microinverters and optimizers add live parts behind each module. Follow the maker’s shutdown steps and name them on the permit.

If a task cannot be done dead, it is energized work. The same OSHA section says only qualified persons may work on circuits that have not been de-energized. They need the right tools and protective gear. Treat it as a separate permit with its own risk assessment. NFPA 70E, the Standard for Electrical Safety in the Workplace, is written to reduce exposure to shock, electrocution, arc flash and arc blast. NFPA lists the 2027 edition as current.

Working at Height, Hot Work and Confined Spaces

Solar crews work on roofs, so the working-at-height permit is often the one you issue most.

A height permit should confirm:

• The roof is safe to stand on, with no fragile sheets or open skylights.
• Anchor points or a lifeline system have been inspected.
• The fall protection plan is clear. Use guardrails, nets or a fall arrest system as the rules require.
• The area below is kept clear of people.
• The weather is acceptable for the work.
• A rescue plan exists for a worker who falls.

US rule. In construction, OSHA requires protection for workers on a surface with an unprotected edge 6 feet (1.8 m) or more above a lower level. It also covers holes, including skylights, more than 6 feet above a lower level. Source: 29 CFR 1926.501.

UK rule. The Work at Height Regulations 2005 define work at height as work where a person could fall far enough to be hurt. There is no height threshold. The regulations also say work at height must be planned, supervised, and done only when the weather does not put people at risk. Source: Work at Height Regulations 2005.

If you work in both countries, use the stricter rule for your whole company.

Hot work includes grinding, welding and torch work near roofing material or racking. Treat it as a fire risk. Follow your insurer’s and your local fire rules for fire watch time.

Confined spaces. A confined space is large enough to enter, has limited ways in or out, and is not made for people to stay in. A battery room or a below-ground cable vault may count. OSHA’s general industry rule, 29 CFR 1910.146, requires an entry permit for permit-required confined spaces. It does not apply to construction. Construction has its own rule, 29 CFR 1926.1201.

Which Rules and Standards Apply?

The 6 ft figure is from 29 CFR 1926.501. The USD 35 fee is from the SolarAPP+ installer cost help article, updated 6 July 2026. The IEC 62446 parts are listed in the table above. The 7 steps are this guide’s own process, not a legal requirement.

Which US rule applies depends on whether the work counts as construction or general industry. Ask your safety adviser. HSE describes HSG250 as aimed at the petroleum, chemical and allied industries. Use it as a model for the process, not as a solar rule.

IEC 62446-2 is the part that talks about worker safety in maintenance. When your permit closes with the test results attached, your safety record and your maintenance record stay in one place. See the solar commissioning checklist. For US rules in more depth, see OSHA compliance for solar installers. For the training your authorized people need, see solar O&M technician training.

Digital PTW vs Paper

Both work if the crew uses them. Here is how they differ.

Paper often suits a small crew that works on few jobs at a time. Digital suits many sites and many open permits. The worst case is a mix: a digital system nobody updates, plus verbal approvals on the side.

A PTW that is only a ritual protects no one. If the same hazards are copied each time and nobody walks the site, crews stop trusting it. Check behavior, not binders. The issuer should be able to point to each isolation point in the field when asked.

Accurate single-line diagrams and string maps make isolation plans honest. A single-line diagram (SLD) is a simple drawing of how the system is wired. If the design names every string and combiner, the permit writer lists real isolation points. See SurgePV’s solar designing and solar proposals.

Common PTW Failures and How to Audit Them

These failures are worth checking for on any site. Each has a low-cost fix.

1. Blanket permits. One permit covers all work on a site for a month. Fix: one permit per task, per crew, per shift.
2. No test before touch. Isolation was done but nobody tested at the work point. Fix: a required field for the meter, the reading and the tester.
3. Orphaned locks. Shift changes leave locks whose owners went home. Fix: a lock register that matches the permit register.
4. Contractor permits in a vacuum. Subcontractors bring their own paper. Fix: all work on your site runs on your permit system.
5. Permits closed with no test records. The inverter is back online but the closeout data is missing. Fix: the permit cannot close until the records are attached.

Audit on a schedule. Pull a sample of closed permits, walk some of them on site, and talk to the people who accepted them. Score each against the 7 steps. Review the score where you review incidents.

Checklist Summary

Use one permit per task. Name each isolation point. Lock and tag each one. Test at the work point before anyone touches a part. Keep the form to one page. Attach the test records at closeout. Audit what crews do, not only what they write. The installation steps in our solar installation hub show where each permit fits in the job.

Frequently Asked Questions

What is a permit to work (PTW) in solar installation?

A permit to work is a signed document that lets one crew do one risky task on one asset for a set time. It records the hazards, the isolation points, the tests and the sign-offs. On solar sites it covers DC string work, inverter and battery work, and roof work.

When is a permit to work required for solar work?

Issue a PTW for tasks with live electrical parts, stored energy, work at height, confined spaces or hot work. A routine look from a safe place may need only a written risk assessment. Your safety adviser and local law set the rule for your site.

What is the difference between a PTW and an AHJ solar permit?

An AHJ permit is the construction approval from the local building or electrical authority before you install. A PTW is a company safety control for hazardous tasks during construction and maintenance. The AHJ permit decides whether you may build. The PTW decides how the crew works safely.

Does OSHA require a permit to work for solar?

OSHA’s rules set duties for electrical lockout and tagging, fall protection at 6 feet (1.8 m) in construction, and confined spaces. A PTW is one way to show those duties were met. For permit-required confined spaces in general industry, 29 CFR 1910.146 requires an entry permit.

What should a solar PTW template include?

The form needs 10 fields. They are site and asset ID, task, hazards, isolation points with lock and tag numbers, and test result. They also include protective gear, valid times, signatures, any change or suspension, and a closeout section with test records. Keep it to one page.

How does lockout-tagout work on a solar PV system?

You cannot switch the array off, so you isolate and lock every disconnect that feeds the work point. That includes AC, the inverter DC switch and the strings you will touch. You release stored energy and lock and tag each disconnect. Then a qualified person tests the work point with a meter. The test includes stray voltage and backfeed.

What does IEC 62446 cover?

IEC 62446-1 covers documentation, commissioning tests and inspection for grid-connected PV systems. IEC 62446-2 covers maintenance, including worker safety. IEC TS 62446-3 covers outdoor infrared thermography. Attach the test records your procedure calls for when you close a permit.