Quick answer
Grid-Tied Inverter A grid-tied inverter is an inverter built to run in step with the utility grid. It matches the grid’s voltage and frequency, sends extra solar power out through your meter, and must stop feeding the lines if the grid goes down.
In the code it is called "utility-interactive". Today it must also be a smart inverter: listed to UL 1741 SB and able to ride through small grid disturbances under IEEE 1547-2018.
Quick facts
The key facts about grid-tied inverter, with sources:
Key takeaways
- Grid-tied describes how an inverter behaves toward the grid, not what kind of box it is. String, micro and hybrid inverters can all be grid-tied.
- Since IEEE 1547-2018, a grid-tied inverter must ride through short dips instead of tripping at the first flicker.
- Look for "UL 1741 SB" on the data sheet. Older "SA" listings were written for California Rule 21.
- Your utility, not you, picks the settings: ride-through category, volt-var curve and trip points.
- It still must shut off in an outage. Backup needs a battery and a device that islands your home.
What "grid-tied" adds to an inverter
Every solar inverter turns panel DC into AC. A grid-tied inverter does it while locked onto the grid. It reads the grid’s wave and builds its own to match. The DOE calls this "grid-following": it needs a signal from the grid to know when to switch.
That is the old core. The newer part is behaviour. An NLR (formerly NREL) presentation on IEEE 1547-2018 lists what a "modern" inverter adds to a "legacy" one: voltage regulation, ride-through, interoperability (talking to the utility) and the option to form an island on purpose.
The whole-system view, with meters and export credit, lives on the grid-tied solar page. This page is about the inverter’s grid rules.
Ride-through: why it no longer trips at every flicker
Under the 2003 standard, inverters tripped off quickly when voltage or frequency moved. That was safe on one street. With millions of inverters, NLR notes, a single transmission fault can sag voltage over a wide area. If every inverter tripped at once, the grid would lose a large block of power at the worst moment.
IEEE 1547-2018 fixes this with ride-through. The inverter must stay connected through short dips in voltage and frequency, through fast frequency changes, and through phase jumps.
Only if a disturbance lasts too long or goes too far does it trip. The DOE describes the same rule for household inverters: stay on through small disruptions, shut down for long or large ones.
NLR stresses that ride-through is a capability built into the hardware. The trip points, by contrast, are settings the utility chooses inside a range the standard allows.
The IEEE 1547-2018 performance categories
| Category | Covers | What it means |
|---|---|---|
| A (normal) | Voltage regulation | Constant power factor, constant reactive power and volt-var. Attainable by all current DER. |
| B (normal) | Voltage regulation | Everything in A plus watt-var and volt-watt, for feeders with lots of solar. Attainable by most smart inverters. |
| I (abnormal) | Ride-through | Essential bulk-grid needs; rate-of-change ride-through of 0.5 Hz/s |
| II (abnormal) | Ride-through | Full coordination with bulk-grid reliability (e.g. NERC); 2.0 Hz/s |
| III (abnormal) | Ride-through | For very high solar levels such as California and Hawaii; 3.0 Hz/s |
The smart functions, in plain words
Volt-var. When local voltage runs high, the inverter absorbs "reactive power", which pulls voltage down. When it runs low, it supplies reactive power. Reactive power does no work itself, the DOE explains, but it keeps voltage and current in step so the grid runs efficiently.
Volt-watt. If voltage stays high, the inverter trims its real power output a little. On a crowded street this can shave some production on sunny afternoons.
Frequency-watt (droop). If grid frequency climbs, the inverter cuts output to help bring it back. NLR lists this as mandatory for Categories II and III when frequency runs high.
Interoperability. The standard requires a communication interface so the utility can monitor and, where allowed, change settings. IEEE 1547-2018 says the utility’s approval is needed for the inverter to actively regulate voltage.
Anti-islanding: the rule that has not changed
An "island" forms when a section of the grid is cut off but an inverter keeps it live. A line worker could touch a wire they think is dead. IEEE 1547 requires that the inverter detect the island and stop energizing the grid within two seconds.
Ride-through and anti-islanding work together. The inverter rides through a brief dip but still detects a true outage and stops. Georgia Power’s residential summary puts it plainly: when grid power is lost, the inverter "must cease-to-energize".
That is why a grid-tied home goes dark in a blackout. To keep power, the system needs a hybrid inverter or a battery with a transfer switch that opens your home from the grid first.
Example: reading the grid lines on two real data sheets
The listing lines tell you which rule set the inverter was tested to. Both lines below are copied from the makers’ sheets.
| Inverter | What the sheet says | What it tells you |
|---|---|---|
| Enphase IQ8 Series (DSH-00378-5.0, July 2026) | "CA Rule 21 (UL 1741-SA)... IEEE 1547:2018 (UL 1741-SB 3rd Ed.)" 6 | Tested to the current national smart-inverter rules |
| SolarEdge SE10000H (12/2020 sheet) | "UL1741, UL1741 SA... IEEE1547, Rule 21" 7 | An older sheet: SA, not SB. Ask for the current revision. |
Enphase also notes its units ship with default IEEE 1547 settings, and that region-specific changes may be requested by the inspector or utility and made through its gateway during installation 6. That is how your utility’s settings get onto the inverter.
Where you see "grid-tied" on paperwork
On the interconnection application, utilities ask for the inverter make, model and AC rating. Georgia Power requires spec sheets showing UL 1741 SB and IEEE 1547-2018 listing.
On the California Energy Commission list, a widely used reference, an inverter is listed for Supplement SB only if the maker shows UL 1741 3rd Edition and compliance with IEEE 1547-2018 and IEEE 1547.1-2020.
On the inverter label and the plan set, look for "utility-interactive" and the listing mark. The inspector checks this.
What modern grid-tied rules mean for you
Benefits
- Fewer nuisance shut-offs during brief grid dips, so more production is kept.
- Helps the local grid hold voltage, which lets more homes on a street add solar.
- Standard national listing (UL 1741 SB) makes approval simpler.
- Settings can be changed by software rather than replacing hardware 6.
Trade-offs
- Volt-watt can trim output on high-voltage feeders.
- Still no power in an outage without a battery and islanding equipment.
- Older inverters listed only to SA may not meet a utility’s current rules.
- Settings are the utility’s call; you cannot simply turn functions off.
What a grid-tied inverter cannot do
It cannot run your home alone during an outage unless it is part of a system built to island. Some newer microinverters can form a microgrid, but only with the maker’s controller and meter collar 6.
It cannot export beyond what your utility approves. Your AC size is set in the application. See inverter sizing for how that number is chosen.
It cannot fix a weak local grid by itself. Smart functions help at the margin; the utility decides how much solar a feeder can host. The hosting capacity lookup shows where maps exist.
Cost and life: what grid rules change
We do not list prices. Grid-tied rules affect cost mainly through compliance: an inverter must carry current listings, and a non-compliant one may need replacing before your utility approves a change. Listing status matters most when you replace an old inverter or add a battery.
Life and warranty are set by the inverter type and maker, covered on the solar inverter page. Plan replacements with the inverter replacement planner.
How a grid-tied inverter gets approved and switched on
Your installer and a licensed electrician handle every step. You sign the application.
- The installer picks an inverter on the utility’s accepted list, with UL 1741 SB listing.
- They file the interconnection application with the inverter spec sheet.
- The utility reviews it and sets any required settings or category.
- The electrician installs the inverter; settings are loaded at commissioning 6.
- The local inspector signs off on the electrical work.
- The utility grants permission to operate. Only then is the inverter turned on for export. See permission to operate.
Settings over time
Grid rules change. A utility may ask for new settings years after install. On many current inverters this is a remote or gateway update 6. Keep your installer’s contact and your monitoring login, so updates can be pushed.
If your inverter goes offline after an update, or starts tripping more often, ask the installer to confirm the settings profile matches what the utility approved.
Warning signs and when to call a pro
- Frequent "grid fault", "over-voltage" or "frequency" codes in the app.
- The inverter stays off after the grid comes back for longer than normal.
- Lights flicker when solar is producing.
- Any of these: call your installer. They read the event log and check settings with the utility.
Safety rule
Never bypass anti-islanding or connect a generator or inverter to home wiring without a listed transfer device. It can energize lines a utility crew believes are dead.
The rule set: UL 1741 SB, IEEE 1547-2018 and IEEE 1547.1-2020
IEEE 1547-2018 (published 6 April 2018) is the US standard for how distributed energy resources connect to and interoperate with the grid. It sets ride-through, voltage regulation, interoperability and anti-islanding.
IEEE 1547.1-2020 is the test procedure that proves an inverter meets 1547-2018.
UL 1741 Supplement SB, in the 3rd edition, is the product listing that applies those tests. The CEC requires UL 1741 3rd Edition for an SB listing.
UL 1741 SA was the earlier supplement built around California’s Rule 21. Many older sheets show SA only.
Which edition your utility enforces, and from when, is in its interconnection rules. Ask your installer to confirm.
Grid-tied inverter vs related terms
| Term | What it means | Talks to the grid? |
|---|---|---|
| Grid-tied inverter | Syncs with and exports to the grid; must follow IEEE 1547 | Yes |
| Hybrid inverter | Grid-tied plus battery port; can island with backup gear | Yes |
| Off-grid inverter | Forms its own grid from a battery; no utility link | No |
| Grid-tied solar | The whole system, including meter and export credit | Yes |
| Central inverter | Plant-scale grid-tied unit; same core listings | Yes |
Misconceptions
- Myth A grid-tied inverter should trip at the first flicker to be safe.
- Reality Not any more. IEEE 1547-2018 requires ride-through of short events while still detecting real outages 2.
- Myth UL 1741 SA and SB are the same.
- Reality SA was built around California Rule 21; SB applies IEEE 1547-2018 via IEEE 1547.1-2020 4.
- Myth I can choose my own grid settings.
- Reality The utility specifies modes and settings; the installer loads them 2 6.
- Myth Grid-tied means no backup is possible.
- Reality Backup is possible with a battery and islanding gear; the inverter alone cannot do it.
Grid-tied rules in SC, GA and VA
Georgia Power requires inverter spec sheets with UL 1741 SB and IEEE 1547-2018 listing, and states the inverter must cease to energize when grid power is lost 8.
In South Carolina, Duke Energy Carolinas’ Rider RSC caps residential systems at 20 kW AC 9. Virginia’s residential net metering limit is 25 kW 10.
Settings and listing editions for SC and VA utilities come from each utility’s interconnection rules; ask your installer for the current list.
What to check on your quote
Ask for the inverter data sheet and find the listing line. You want UL 1741 SB and IEEE 1547-2018. If you see only SA, ask whether a newer revision exists and whether your utility accepts it.
If backup matters, ask how the system islands in an outage. A plain grid-tied inverter will not.
Compare inverter types in our inverter types guide.
Questions about grid-tied inverter
What is UL 1741 SB?
UL 1741 SB is the product listing that shows an inverter meets IEEE 1547-2018, tested with IEEE 1547.1-2020. The California Energy Commission requires UL 1741 3rd Edition for an SB listing. Many utilities, including Georgia Power, ask for it on the spec sheet.
What is the difference between UL 1741 SA and SB?
SA was the earlier supplement, built around California’s Rule 21 smart-inverter rules. SB applies the national IEEE 1547-2018 standard through the IEEE 1547.1-2020 test. New installs are generally expected to show SB. Ask your utility which it accepts.
What does ride-through mean for solar inverters?
Ride-through means the inverter stays connected during short dips or jumps in grid voltage and frequency, instead of tripping off. IEEE 1547-2018 requires it so a single grid fault does not knock out large amounts of solar at once. Long or severe events still make it trip.
Why does my grid-tied inverter shut off in a blackout?
It is required to. IEEE 1547 says the inverter must stop energizing the grid within two seconds of an island forming. This protects utility crews. To keep power on, you need a battery system that can disconnect your home from the grid first.
What is volt-var on an inverter?
Volt-var is a setting where the inverter absorbs or supplies reactive power to nudge local voltage back toward normal. It is one of the Category A functions in IEEE 1547-2018. Your utility decides whether it is on and what curve to use.
Can my utility change my inverter settings?
The utility specifies the settings, and they can be changed locally or remotely under IEEE 1547-2018. Enphase, for example, says region-specific changes requested by the utility or inspector are made through its gateway. Your installer usually carries out the change.
Is every solar inverter a grid-tied inverter?
Almost every home inverter in the US is, because most systems connect to the grid. Off-grid inverters are the exception: they form their own grid from batteries. Hybrid inverters are grid-tied and also manage a battery.
Do I need a smart inverter for solar?
In practice yes. Utilities increasingly require IEEE 1547-2018 functions, shown by UL 1741 SB listing. Georgia Power requires it for residential interconnection. Your installer should pick a model on your utility’s accepted list.
Can a grid-tied inverter work without the grid?
Not on its own. A grid-following inverter needs the grid’s signal to build its AC wave, the DOE explains. Some systems add grid-forming capability with a battery and controller, which lets them run your home as a small island during an outage.
Sources
- IEEE Standards Association, IEEE 1547-2018 Standard for Interconnection and Interoperability of Distributed Energy Resources, retrieved .
- NLR (formerly NREL), Michael Ingram, Getting to 95 (IEEE 1547-2018 overview), NREL/PR-5D00-82894, May 2022, retrieved .
- US DOE Solar Energy Technologies Office, Solar Integration: Inverters and Grid Services Basics, retrieved .
- California Energy Commission, Inverter Listing Request Instructions (Aug 2025), retrieved .
- Carter Machinery / Caterpillar white paper, IEEE 1547 Unintentional Islanding Protection (quotes IEEE 1547 §4.4.1), retrieved .
- Enphase Energy, IQ8 Series Microinverters data sheet (DSH-00378-5.0-EN-2026-07-13), retrieved .
- SolarEdge, Single Phase Inverter with HD-Wave Technology for North America data sheet (12/2020/V01, distributor-hosted copy), retrieved .
- Georgia Power, Behind-the-Meter Interconnection Summary for Residential Customers (rev. 15 Aug 2025), retrieved .
- Duke Energy Carolinas (SC), Rider RSC Residential Solar Choice, retrieved .
- Code of Virginia §56-594 (net energy metering), retrieved .
Expert review
Written by the HyreSolar Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Performance categories and ride-through functions from the NLR IEEE 1547-2018 presentation; grid-following and reactive power from DOE; listing rules from the CEC instructions; listing lines and settings statement copied from named Enphase and SolarEdge sheet revisions; Georgia Power requirements from its residential summary.
Suggest a correction. We fix errors and say what changed.