If you’ve been in solar long enough, you know one thing for sure — Grounding and Bonding Solar mistakes can kill your inspection pass rate.
Even the cleanest install can fail if your grounding paths aren’t continuous or bonding lugs aren’t UL-listed. It’s not about the look — it’s about the path of fault current and code compliance.
In this blog, we’ll dig deep into what inspectors look for, why Grounding and Bonding Solar errors are so common, and how to bulletproof your solar systems against grounding and bonding failures.
1. Why Grounding and Bonding Matter More Than You Think
Grounding and bonding aren’t just NEC checkboxes — they’re your safety backbone. They ensure any stray current or fault energy has a low-resistance path back to the source, preventing shock, fire, or damaged equipment.
- Grounding = connecting the electrical system to the earth (safely dissipating fault current).
- Bonding = connecting all metal parts together so no potential difference exists between them.
In a PV system, both must be correctly implemented — from modules and rails to combiners, inverters, and service panels.
2. The Most Common Grounding and Bonding Mistakes Contractors Make
Even seasoned installers trip up on these NEC details. Here are the big ones inspectors flag most often:
a. Missing Equipment Grounding Conductors (EGCs)
Skipping EGCs between arrays or forgetting to bond racking sections separately leads to discontinuous grounding. Remember — painted aluminum rails don’t conduct well.
Fix: Always use UL-listed bonding jumpers or grounding washers to ensure continuity across rails.
b. Non-Listed or Improvised Bonding Hardware
Improvised solutions (like self-tapping screws or unlisted lugs) are an instant red flag. Every bonding component must be UL 2703 or UL 467 listed.
Fix: Use manufacturer-approved grounding mid clamps, lugs, and jumpers that match your racking system.
c. Incorrect Ground Rod Installations
A single 8-ft rod may not meet resistance requirements, especially in dry or rocky soil.
Inspectors may require dual rods spaced at least 6 ft apart.
Fix: Always check soil resistance and local AHJ requirements before finalizing grounding electrode design.
d. Inconsistent Conductor Sizing
EGCs must be sized per NEC 250.122, based on overcurrent device rating. Undersized EGCs cause both safety hazards and code violations.
Fix: Match your conductor size to the OCPD rating and ensure bonding jumpers are equal or larger.
e. Floating Metallic Components
Rails, junction boxes, or equipment enclosures not properly bonded can hold stray voltage. Inspectors will test continuity between all metallic parts — any open path = automatic fail.
Fix: Continuity-test your full grounding system before inspection. Use a multimeter between module frames, rails, and ground electrode.
3. Understanding NEC Code References (2020 / 2023)
Most AHJs now follow NEC 2020 or 2023, which added clarity around PV grounding and bonding.
Key sections every contractor should memorize:
- NEC 690.43: Equipment grounding and bonding requirements for PV systems.
- NEC 690.47: Grounding electrode system connections.
- NEC 250.136(A): Bonding of separately derived systems.
- NEC 250.102(C): Sizing bonding jumpers and grounding electrode conductors.
Knowing these references not only keeps you compliant — it also builds inspector trust.
4. How to Pass Grounding and Bonding Inspections Every Time
- Use only UL-listed components for bonding/grounding.
- Torque everything — inspectors check for loose lugs and under-torqued fasteners.
- Label grounding points clearly on as-builts and one-line diagrams.
- Verify continuity from each module to main service ground.
- Follow racking manufacturer instructions — they often specify bonding hardware locations.
- Document everything with photos before covering conduits or junction boxes.
5. Real-World Example
A 15kW roof-mount project failed inspection twice due to “incomplete bonding.” The issue? The installer used self-drilling screws instead of bonding jumpers between mid-rails.
Correction took 3 days, plus $400 in labor and reinspection fees.
One missing jumper = one lost week of revenue.
6. The Smart Fix: Partner with a Permit Design Expert
If you’re handling 10+ installs a month, manually verifying each grounding detail is time-consuming. Partnering with a dedicated solar permit design team ensures your plan sets meet NEC grounding and bonding standards upfront.
Teams like Vishtik design with precision, ensuring your permit drawings include:
- Proper grounding paths per NEC 690 & 250
- Accurate conductor sizing
- AHJ-specific grounding details
- Bonding component callouts (UL listed)
This means fewer corrections, faster approvals, and smoother inspections.
Stop Failing Inspections — Build It Right from the Start
Grounding and bonding errors are avoidable — if you design smart.
Let Vishtik’s permit design experts engineer your next plan set with compliant grounding layouts, accurate NEC references, and zero inspection surprises.
Request your solar permit design now at www.vishtik.com
