How to Wire Solar Panels With Microinverters

Microinverters convert direct current energy (DC) from solar panels to usable alternating current electricity (AC) for facilities, homes, etc. Because microinverters allow easy addition of more solar panels to the system in the future and have a longer warranty, they are often preferred to other solar inverters.

Connecting solar panels to microinverters is essential as solar energy is best used indirectly from the solar power inverter. Correct wiring ensures the optimal operation of solar products and prevents damage to your wiring system. 

This post highlights the requirements for wiring solar panels with micro inverters and the steps for proper wiring.

Electrical and Grounding Requirements

Wiring solar panels with micro-inverters is an easy task. This task is more manageable when all necessary components are set and properly grounded. For a successful operation, the following equipment must be bonded electrically and grounded.

• The PV panel frames
• The panel support rails (such as ground bonding across splices in the rail)
• The micro-inverter case grounds
• Metal PV array junction box
• Metal disconnect switch of the house

Some regions may have other electrical bonding requirements that can be researched and applied. In addition, It is essential to bond this equipment using a code-approved method to ensure a safe and reliable operation. 

The Number and Placement of Microinverters

Microinverters are usually connected to individual solar panels and linked together, however, that is not always the case. Some microinverters take two panels, and some can take four. When placing panels on a rooftop, the number of panels on each section will influence how many microinverters to use, the electrical connections required, and how many rails and brackets are needed.

While rooftop placements are often convenient and least intrusive, ground placements allow for a solar array that is as big as your budget allows. Ground-based arrangements offer more flexibility in panel positioning and microinverters connection.

Safety Tips

All wiring operations should be done by professionals or skilled technicians with ample experience in construction and electrical work.

These safety tips should be followed to avoid clipping, errors, or destruction of equipment.

• Ensure all grounding requirements are met, as some microinverters are sensitive to the grounding points.
• Make sure extra wires are left in the junction box to allow for future reconnections.
• Mark the disconnection switch and PV feed circuit breaker with appropriate placards.
• Place the disconnection switch near the meter (less than 10 ft away).
• Communicate with inspectors if in doubt about any wiring issue.

Steps in Wiring the Solar Panel To the Microinverter

Below are the steps taken to wire a solar panel with microinverters.

Step 1: Wire the PV Panel Array Junction Box

From a junction box out of the PV panel array and using an interconnect cable, connect the first microinverter to the wiring that goes to the facility. The junction box wiring connections include the following:

• Connect the black and Red (L1 and L2) inverter cord wire to the black and red wire from the facility.
• Connect the neutral (blue) inverter cord wire to the neutral wire (white) from the facility.
• After installing a ground lug, connect the ground wire from the facility and the ground wire from the micro-inverter cases. 
• Attach the ground lug properly to the box so that it makes good electrical contact.

Step 2: Wire the Disconnect Switch

The disconnection switch is used to disconnect the PV panel array and ensure it does not power the grid. It is best placed within 10ft of the meter but can be placed at further distances in certain conditions. This switch is a standard item that can be purchased from many electrical supply stores. It should be placed in a safe location and should have a means of locking in its off position.

The disconnection switch wiring connections are as follows:

• Connect the two leads (black and red) from the junction box to the lower switch lugs.
• Attach these red and black leads through the power distribution panel to the top switch lugs.
• Connect the neutral wires (white) from the junction box and the power distribution box.
• After installing a ground lug, connect the ground wire from the facility power distribution panel and the junction box. 
• Attach the ground lug properly to the box so that it makes good electrical contact.

Step 3: Connecting the Facility Wiring-The PV Feed-in Breaker

When using a meter without a power distribution panel, a new PV feed-in breaker in the circuit breaker box is required. Because the wiring is live, it is important to be safe when handling the installation. Ensure the circuit breaker and disconnect switch are off while installing.

The PV feed-in breaker wiring connections are as follows:

• Connect the leads (black and red) from the disconnect switch to the new circuit breaker terminals.
• Attach the neutral wires (white) from the switch to the neutral bus in the distribution panel.
• Connect the ground wire (green) to the distribution panel ground bus.

Step 4: Wire The PV Panels and Inverters and Bring The System Up

This final step includes connecting the PV panels to the microinverters and starting the system. This is done when the sun is down. During the day, cover the PV panels before connecting them to their inverter.

• Connect the DC leads from the PV panel to the two DC input leads from the micro-inverter. Note that the inverter must have the same connector type as the PV panel.
• For the last microinverter, screw the cap of the female connector to protect it from the weather. Then, fix the cord with the male connector into the thread with the female connector on the next inverter.

• Do the same with the remaining micro-inverters.
• For the final micro-inverter (closest to the junction box), plug the male cord from the last inverter into the female cable from the junction box that was wired earlier.

Finally, after checking all the wiring, plug in the EMU unit put on the feed circuit breaker, and turn on the disconnect switch. If there is sun on the panels, the reading will appear on the EMU display. The EMU also shows the number of inverters online.

Merging New Panels and Old Ones

Merging new panels with old ones, such as IQ microinverters and non-IQ microinverters, requires compatibility and communication of production, receiving updates, etc., between the microinverters. 

With the help of a Module Compatibility Calculator, compatibility of the microinverters can be confirmed prior to purchase. And using an IQ envoy, new and old panels can be merged successfully as this equipment allows communication between the micro inverters.

Conclusion

Wiring solar panels with micro inverters can be done quickly as it mainly involves simple push-in connections. To enjoy lasting use of microinverters and solar panels, these connections must be made safely and reliably using products from trusted companies.

For a wide range of quality solar panels and microinverters, and other solar PV protection products, contact Beny-the leading brand for quality DC protection products and EV charging stations.