Quick Answer
Okay, so here's the quick version. Your solar production's in the tank and you're thinking it's the wiring. Nine times out of ten, you're right. It's usually a loose MC4 connector you can just click back in, some critter chewing on a wire, or a connection that's finally given up the ghost from sun and rain. A simple fix might cost you nothing but your time. If it gets complicated and you need a pro, you're looking at a few hundred bucks for a service call. But first, let's see what we're dealing with.
Common Symptoms
Possible Causes
Step-by-Step Diagnosis
Step 1
Check your solar monitoring app to see which part of the system is underperforming.
Step 2
Do a careful visual inspection of all accessible wiring from the ground and on the roof for obvious damage.
Step 3
Physically check that all MC4 connectors are securely clicked together.
Step 4
Check the inverter screen for any specific error codes and look them up in the manual.
Step 5
If you are qualified, use a multimeter to test DC voltage at the inverter to isolate the problematic string.
Step 6
For persistent issues, a professional should perform an insulation resistance test to find ground faults.
DIY vs Professional Costs
| Repair Type | DIY Cost | Professional Cost | Time Required |
|---|---|---|---|
Tightening a loose MC4 connector | $0 | $150-400 | 5-30 minutes |
Replacing a single damaged MC4 connector | $10-30 | $250-500 | 1-2 hours |
Repairing extensive animal damage to wiring | Not Recommended | $500-1500+ | 4-8 hours |
When to Call a Professional Solar
- The inverter displays 'Arc Fault' or 'Ground Fault' errors.
- You cannot easily see the source of the problem after a thorough visual inspection.
- The repair requires working on a high or steep roof you are not comfortable or safe on.
- Any repair that involves cutting, splicing, or replacing primary system wiring.
- Your system is still under an installer's workmanship warranty (let them fix it to avoid voiding the warranty).
Prevention Tips
- Hire a reputable, experienced installer who uses high-quality components and proper wire management techniques.
- Perform a visual inspection of your system every few months to look for changes or potential issues.
- Install a 'critter guard' (wire mesh barrier) around your solar array to prevent animals from getting underneath.
- Keep tree branches trimmed back so they cannot rub against panels or wiring conduit.
Frequently Asked Questions
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