Do microinverters work during a power outage?

Not by themselves. Grid-tied systems are designed to switch off when the grid goes down so they do not energize utility lines. Backup takes a battery and transfer equipment that isolate your home from the grid.

Can AJ Long Electric replace a microinverter on a system another company installed?

Yes. We service systems other companies installed, including systems whose installer has closed. Troubleshooting is priced separately, and estimates are free.

Where is the rapid shutdown switch on my house?

For one- and two-family homes, the code puts the initiation device at a readily accessible outdoor location, usually the service disconnect or a labeled PV disconnect near the meter. We show you where it is at closeout.

Do microinverters need to be replaced like a string inverter?

The Department of Energy says string inverters usually last 10 to 15 years, while microinverters tend to have lifetimes similar to the panels. Individual units can still fail, and monitoring shows which one.

Microinverters

Why We Install Microinverters

Name: AJ Long Electric
Address: 2724 Dorr Ave, Suite 102, Fairfax, VA, 22031, US
Telephone: (571) 444-6886

A microinverter sits under each panel and turns that panel's DC power into AC on the roof. We use module-level electronics where they earn their place: they meet the rapid shutdown rule at the panel, keep one shaded panel from pulling down the rest, and report production panel by panel.

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Reviewed 2026-09-24

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Answer first

Microinverter installation, in short

We mount one microinverter on the racking under each panel, run AC branch circuits across the roof to a combiner, and connect the combiner to your service panel through a backfeed breaker or a line-side tap. The inverter choice is made for your roof and your panel, not by default. On a single, unshaded roof plane a string inverter can be the better fit, and we will say so.

Rapid shutdown at the module: the National Electrical Code (Section 690.12) requires it on rooftop systems so firefighters can de-energize the array.
Shade tolerance: shade or damage on one panel does not reduce the output of the others.
Monitoring panel by panel, so a single failed panel shows up as one line, not a vague drop.
No wall-mounted string inverter to replace on the typical 10 to 15 year cycle the Department of Energy describes for string inverters.

Why module-level electronics

A string inverter takes the combined DC output of a series of panels and converts it to AC in one box, usually on an exterior wall or in the garage. The Department of Energy puts the trade-off plainly: a string setup is cost-effective, but if one panel is shaded or has a problem, production drops on the whole string.

With a microinverter on every panel, each panel works on its own. DOE notes that shading or damage on one panel will not affect the power drawn from the others. Rooftop wiring becomes AC branch circuits, and the only DC on the roof is the short lead between each panel and its microinverter.

Rapid shutdown and firefighter safety

Section 690.12 of the National Electrical Code requires photovoltaic circuits on or in buildings to include a rapid shutdown function to reduce shock hazard for firefighters. Sunlight keeps panels energized even when the grid is down, and UL Standards & Engagement notes that damaged arrays present a shock risk to first responders.

The code sets limits on both sides of the array boundary, which it defines as one foot from the array in all directions:

Outside the array boundary, controlled conductors must drop to 30 volts or less within 30 seconds of shutdown initiation.
Inside the boundary, the system must either limit voltage to 80 volts or less within 30 seconds or use a listed PV hazard control system (UL 3741).
For one- and two-family homes, the initiation device must be at a readily accessible outdoor location. We label it and show you where it is at closeout.
Microinverters meet the inside-the-boundary limit at each panel. When the initiation device is switched off or grid power drops, each unit stops producing.

Shade on Fairfax County roofs

Much of Fairfax County sits under mature tree canopy. Morning shade on the east end of an array, a chimney shadow that sweeps across two panels in the afternoon, or leaves on one corner in fall are the conditions we design for most often.

With microinverters, those panels produce less while the rest of the array keeps producing at full output. Your proposal shows a modeled estimate that accounts for your shade, and we still tell you when a tree or a roof plane is not worth the panels.

Monitoring you can use

Microinverter systems report production for each panel through a gateway connected to your home internet or a cellular link. You see the array on a phone app, and we can see it too when you give us access.

Panel-level data makes service faster. A panel that goes to zero while its neighbors keep producing points to that microinverter, its connector, or that module. On a string system, the same failure shows up only as lower total output.

Solar service and repair

The electrical side we handle

Microinverter branch circuits land in an AC combiner, and the combiner connects to your home at the service panel. That connection is where an electrician-led company earns its keep: backfeed breaker sizing under the 120 percent busbar rule, panel age and capacity, grounding and bonding, and a service upgrade when the existing panel cannot take the solar breaker. A master electrician is on site for every solar project.

Straight answers

Questions

Do microinverters work during a power outage?: Not by themselves. Grid-tied systems are designed to switch off when the grid goes down so they do not energize utility lines. Backup takes a battery and transfer equipment that isolate your home from the grid.
Can AJ Long Electric replace a microinverter on a system another company installed?: Yes. We service systems other companies installed, including systems whose installer has closed. Troubleshooting is priced separately, and estimates are free.
Where is the rapid shutdown switch on my house?: For one- and two-family homes, the code puts the initiation device at a readily accessible outdoor location, usually the service disconnect or a labeled PV disconnect near the meter. We show you where it is at closeout.
Do microinverters need to be replaced like a string inverter?: The Department of Energy says string inverters usually last 10 to 15 years, while microinverters tend to have lifetimes similar to the panels. Individual units can still fail, and monitoring shows which one.

Sources

Next step

Find out which inverter fits your roof

A free roof study checks your shade, roof planes, and service panel, then recommends the inverter and shows a modeled production estimate.