On-grid (grid-tied) solar system diagram

What the diagram shows

The on-grid (grid-tied) system is the most common type of residential PV installation. The panels produce direct current, the inverter converts it into alternating current synchronized with the grid, and the home uses the energy at the same moment. What is left over is exported to the utility grid and recorded by a bidirectional meter.

The diagram follows the energy path from left to right: panel array → combiner box → inverter → AC breaker → distribution board → home, with the board also connected to the bidirectional meter and the utility grid. Below the board sit the AC SPD and the earthing. The equipment enclosures go to the earth busbar, connected to the earth rod.

Diagram components

• Panel arrayGroup of modules shown as a block.
• Combiner boxString combiner and protection box.
• InverterConverts DC into AC (on-grid).
• AC breakerBreaker for alternating-current circuits.
• Distribution boardSystem distribution and protection board.
• Bidirectional meterBidirectional energy meter (generates and consumes).
• Utility gridConnection point to the utility.
• HomeResidential consumer unit.
• AC SPDSurge protector for alternating current.
• Earth busbarEarth equipotential bonding busbar.
• Earth rodEarth (ground) rod driven into the soil.

How it works, step by step

1. Generation: the panel array produces direct current while there is light. In residential systems, the modules usually form one or two strings.
2. DC protection: the combiner box groups the fuse, the DC SPD and the isolator: it disconnects the panels from the inverter for maintenance and diverts DC-side surges to earth.
3. Conversion: the inverter tracks the maximum power point (MPPT) and delivers alternating current at the local grid voltage (230 V in most countries; 120/240 V in North America).
4. AC protection and distribution: the AC breaker protects the circuit up to the board, from where the energy flows to the home circuits.
5. Metering and grid: the bidirectional meter records what the home imports from the grid and what it exports; depending on the local rules, the exported energy is credited or paid under net metering, net billing or feed-in schemes.
6. Surges and earthing: the AC SPD in the board protects the circuits against surges from the grid, and the earth busbar connects the combiner box, the inverter and the SPD to the earth rod.

When to choose on-grid

On-grid makes sense when the main goal is to lower the electricity bill and the local grid is reliable. It is the system with the lowest cost per installed kWp and the simplest maintenance, because it has no batteries.

The limitation matters: during a power outage the inverter shuts down for safety (anti-islanding protection), even in full sun. If outages are a problem where you live, compare it with the hybrid template with battery.

Tips to adapt the template

• Replace the panel array with two strings if the roof has two orientations and the inverter has two MPPT inputs.
• To show each DC-side protection, replace the combiner box with a separate DC fuse, DC SPD and isolator.
• Use the connection labels to show voltages ("String 1", "230 V AC") and each item’s description to note power ratings.
• Use an area titled "Roof" to group the panels and make the drawing easier to read.

Frequently asked questions

Does an on-grid system work during a power outage?

No. For safety, the on-grid inverter shuts down when the grid fails, even if there is sun, so it does not energize the grid while technicians work on it. To keep the home running during an outage you need a hybrid system with a battery.

Do I need a new meter?

Often. To record exported energy, the utility may install a bidirectional (import/export) meter or reprogram the existing one as part of the connection process. The procedure varies by utility and country.

Can I expand the system later?

Usually yes, as long as the inverter has spare capacity or a second inverter is added. In the diagram, just duplicate the panel array and connect it to a new inverter input.