Wrapping up the installation of solar panels on the second rack!
This video completes the installation of solar panels on the second mounting rack, focusing on securing the final panel, finishing mechanical fastenings, routing and connecting PV wiring, and grounding. The wrap-up includes sealing roof penetrations, torqueing clamps to spec, installing MC4 connectors and junction hardware, and testing the string for proper voltage and continuity.
Build Sequence
1. Final panel lift and placement
Lift the last panel onto the second rack, align its frame with the adjacent panels and the rail slots so clamps can seat properly.
2. Install mid and end clamps
Install mid clamps between adjacent panels and end clamps at the rail ends, hand-tighten first then torque to manufacturer specification to avoid over-compression.
3. Secure rails to roof and seal penetrations
Verify lag bolts are seated in structural members, apply roof sealant around flashing points, and tighten roof fasteners to spec to ensure water-tight connections.
4. Ground rails and panels
Attach grounding lugs to the rail and bond to the grounding conductor; ensure all metal parts are properly earthened per code.
5. Route PV cabling and install conduit
Run PV-rated cable from the panel leads along the rack into conduit, secure with UV-rated clips, and route to the junction/combiner box location.
6. Make MC4 connections and wire the string
Strip cable ends, crimp and install MC4 connectors, then connect panels in the planned series/parallel configuration and secure branch connectors in the combiner box.
7. Seal and weatherproof all roof penetrations
Apply additional sealant over flashings and around conduit entries, check for any gaps, and ensure all penetrations are watertight.
8. Test the string and commission
Use a multimeter to measure open-circuit voltage and string continuity, verify polarity, then follow inverter/EMS startup checklist to bring the system online.
9. Final cleanup and documentation
Tidy cables, label strings in the combiner, take photos for records, and note torque and installation details for future inspection.
Frequently Asked Questions
How do I test the completed string before connecting to the inverter?
Measure open-circuit voltage (Voc) of the string with a multimeter, check for expected Voc based on module specs and panel orientation, verify polarity, and ensure continuity across connectors before final connections.
VIEW FULL ARTICLE →Can I connect the last panel while panels are exposed to sunlight?
You should avoid making live connections in full sun; it's safer to cover panels or work early/late in the day and use appropriate PPE. Always keep polarity and connector locking in mind to prevent arcing.
VIEW FULL ARTICLE →Related Builds
Basic dash build and small rewire of my 65 Mustang
Part 2 of the solar mount project, 1/2 way done with help from a friend!
I Tried Making a Gauge Cluster PT. 2
I Tried Making a Gauge Cluster and Didn't Expect This
Running a tailgate reverse camera and an amp positive wire in a 2017 Chevy Silverado WT
Light update for the garage!Parts Used (11)
Standard framed PV module used on the rack; exact spec depends on project.
Aluminum rails and racking hardware forming the second mounting row.
PV-rated connectors used to join panel leads and create strings.
Where panel strings are combined and overcurrent protection may be placed.