Lesson 10 of 12 · Chapter 10
Commissioning: Pre-Checks, Performance Verification and Handover
Commissioning is where a solar installation stops being a collection of well-mounted parts and becomes a power system you can trust. The plan set, the labels, the settings, the meter and the system’s real behaviour all have to line up. This lesson covers the pre-commissioning ritual, reading three numbers for coherence, verifying controls, documentation that survives, and a handover the customer can repeat under stress.
Choose how you want to learn
You can change this any time. Every level does the same hands-on steps. Press Listen on any part to hear it read aloud.
- 1 · The pre-commissioning ritual
- 2 · Three numbers that must agree
- 3 · Controls, faults and heat
- 4 · Documentation that survives
- 5 · The handover
- 6 · Try it at home
- 7 · Your card
- 8 · Check yourself
Part 1
The pre-commissioning ritual
Catch problems while everything is still safe, reachable and easy to fix.
Do it the same way every time, from a checklist.
Never turn it on just to see what happens.
Reset the site first: a single metal shaving inside an inverter can become corrosion or a fault. Then match the build to the approved design; if the paperwork doesn’t match the wiring, commissioning will not make it true. On the roof: clamps torqued, bonding hardware listed, flashing complete, conductors supported.
At every enclosure: ratings kept, fittings raintight, bushings in place, terminations seated and torqued with the right tool. Verify CTs and communications, check labels against the as-built, test your meter on a known source, and rehearse the shutdown before you energize.
“Checklists are not paperwork; they are the tool that keeps you from relying on memory when you’re tired, it’s hot, and everyone wants to be done.”
“you are betting the system on your wrist”
“You are trying to make a system that survives five winters.”
Read the whole chapter free in the book reader.
The Pre-Commissioning Bench. Put the chapter’s steps in order, from the last clamp to energizing. The shortcuts are never accepted.
Part 2
Three numbers that must agree
Compare three numbers: what the array should make in today’s sky, the DC the inverter reports, and the AC it delivers.
The goal is not a perfect match. The goal is coherence.
Two strings on the same plane should behave alike.
Nameplate is measured under standard test conditions, not your roof today. Heat, haze and soiling lower output, so don’t call a normal system bad because you expected nameplate at 9 a.m. in winter, or call a poor one fine because it is cloudy.
Healthy DC with low AC points to the AC side: curtailment, grid voltage, heat derating. Uneven DC inputs point to the DC side: stringing, connectors, polarity, a missed shadow. And the labels PV 1 and PV 2 should map to the inverter’s inputs, or troubleshooting later wastes hours.
“Your goal is not a perfect match. Your goal is coherence.”
“If the inverter is already hot enough to derate on commissioning day, it will definitely derate on the first real heat wave.”
The Three Numbers Bench. A new system each round. Read the sky, the DC inputs and the AC output, and decide where they point.
Part 3
Controls, faults and heat
A fault code is data. Read it; don’t cycle the power until it goes away.
A hot termination under load is a warning, not normal.
Check that controls respond logically to a known change.
Energize in the manufacturer’s sequence and watch for immediate faults. Loss hunting means looking for losses that should not be there: excessive voltage drop, clipping caused by a limitation, mismatches that suggest a wiring error. A thermal scan of terminations and breaker landings under load reveals what a visual check can’t.
With export limits or storage, verify the metering direction and watch the flow as a known load turns on and off. For hybrids, test the transitions: outage, isolation, backed-up loads, and a clean return. Record the sky, time, status, readings and any settings you changed.
“If you see a fault, treat it as data, not as a reason to cycle power repeatedly until it “goes away.””
“a termination can lie until it heats”
“Torque is your way of making the system boring, and boring is the goal.”
Four moments during performance verification.
Part 4
Documentation that survives the truck leaving
The as-built must match what is installed, not what was planned.
Record model and serial numbers and take photos for the future technician.
Save the commissioning readings as a baseline.
If anything moved from the permitted design, update the as-built: a disconnect drawn on the wrong wall costs a responder time. Record ratings, breaker and conductor sizes, and the utility settings that matter.
Set up monitoring before you leave, with the right address, time zone and system size; a misconfigured portal is misleading. Document export-limit verification, and for storage the operating mode and the critical loads.
““Close enough” creates expensive confusion later.”
“You are not taking photos for social media.”
Six pieces of documentation. Does it belong in the package, or does it need fixing first?
Part 5
The handover
Teach three things: what the system does, how to shut it down, and what normal looks like.
Walk the equipment together and point to real hardware.
Finished means the customer can explain the shutdown back to you.
Grid-tied solar without storage shuts down during an outage, even in sunshine. With storage, say what is backed up and what normal protective behaviour looks like: reserve limits, a trip on a large motor start. Explain the three layers: the app, the meter, and the utility’s billing rules.
Give simple maintenance rules: watch for drops on clear days, don’t open enclosures, don’t spray the inverter, don’t cycle breakers to fix errors, and who to call. Leave the as-built one-line, manuals, warranties, a shutdown map and monitoring access.
“Customer handover is not a sales pitch.”
“Don’t promise “no maintenance” as if the outdoors is polite.”
“That is how your work survives. Not just through metal and silicon, but through clarity.”
Four handover moments that prevent future phone calls.
Part 6
Try it at home
Do these at home. Nothing here asks you to open equipment or work on a live system. Tick each one when it is done.
Part 7
Your “Commissioning Record” card
The baseline a future technician will thank you for. Nothing you type here leaves this device.
My Commissioning Record
Global Sovereign University · Solar PV Installers, lesson 10
Commissioning on one card
- Reset, match, inspect, then energize.
- Never turn it on to see what happens.
- Coherence, not nameplate.
- A fault is data. A hot lug is a warning.
- As-built matches installed.
- They can explain the shutdown back.
Your work survives through clarity.
Part 8
Check yourself
Six real situations. Pick what you would do. You will see why after each one.
Lesson 10 complete.
You can now run a pre-commissioning ritual, read three numbers for coherence, verify controls, leave documentation that survives, and hand over a system its owner understands. Next: Lesson 11, troubleshooting and maintenance.
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Solar Photovoltaic (PV) Installers by Dr. Gene A Constant. This lesson comes from chapter ten. Read the whole book free in the reader, or keep a copy.
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