Solar module frame grounding lug screw size
M4 · 8 to 12 mm long
The screws used on Solar module frame grounding lug are M4 in lengths from 8 to 12 mm.
It is listed for solar panel frame grounding holes (~4mm) are typically fitted with M4 grounding bolts and lugs.
This entry is marked reported and comes from diysolarforum.com.
An M4 screw is 4 mm in diameter with a 0.7 mm pitch, tapped with a 3.3 mm drill; imperial look-alike: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same.
Solar module frame grounding lug screw specifications
One row per fitment record. Head, drive are shown only where the source states them; pitch is the ISO coarse pitch for the thread.
| Thread | Length | Pitch | Head | Drive | Where it goes | Status |
|---|---|---|---|---|---|---|
| M4 | 8–12 mm | 0.7 mm | not stated | not stated | Solar panel frame grounding holes (~4mm) are typically fitted with M4 grounding bolts and lugs | Reported |
Fitment records and sources
Solar panel frame grounding holes (~4mm) are typically fitted with M4 grounding bolts and lugs
pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20
How to check the screw before you buy
- Take one original screw out first and measure it before ordering; the record above tells you the thread, the original screw tells you the exact length and head.
- Diameter: across the threads an M4 screw measures about 4 mm with calipers (usually a hair under). If yours measures noticeably more or less, it is a different thread.
- Pitch: 0.7 mm from one thread crest to the next (14.29 crests per centimetre). A thread pitch gauge or the pitch-gauge tool settles it in seconds.
- Length: measure from under the head to the tip for pan, button, wafer and cap heads; countersunk (flat) heads are measured overall.
- The records span 8–12 mm, which means different positions take different lengths — match each hole to its own screw.
- Driver: the source does not name the drive. Standard M4 heads take PH2 for Phillips and T20 for Torx, and a 3 mm hex key for socket heads; a bit that fits loosely will cam out and strip the head.
- Tightening: no device-specific torque is published in these records. The site's general figure for M4 is about 2.0-3.0 N·m into metal threads and 0.8-1.4 N·m into plastic bosses; snug it up and stop.
Common mix-ups with M4
- Grounding-lug screws on Siemens and Beckhoff gear (M4) are earth hardware, not structural mounting screws — don't reuse them to hold a module.
- Grounding/earth-stud screws on hazardous-area (ATEX/IECEx) gas detectors are commonly M4 even though the enclosure body uses larger threaded glands — don't extrapolate the earth screw size to the whole unit.
Buy these screws at TechSpare Warehouse
In stock and shipped from South Carolina. Our black screws are Phillips wafer head (low profile); match the head style and length to the original before you order.
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Devices whose records share a thread with Solar module frame grounding lug, closest length match first.
- KERN ABS/ABJ analytical balance also M4 × 8 mm
- Star Micronics mPOP under-counter mount (CM-POP1) also M4 × 12 mm
- TEKTELIC Kona Photon Gen-2 LoRaWAN gateway also M4 × 12 mm
- Solplanet ASW30K-50K-LT-G2 Solar string inverter AC/COM terminal cover screw also M4 × 10 mm
- Cabinet & furniture hardware also M4 × 8–12 mm
- Ikan PT3100 15-inch teleprompter also M4 × 8 mm
- Allen-Bradley PowerFlex 755 IP00 control pod also M4 × 12 mm
- Kern PFB precision balance internal hardware also M4 × 10–12 mm
Questions about Solar module frame grounding lug screws
- What size screw does Solar module frame grounding lug use?
- M4 × 8–12 mm for solar panel frame grounding holes (~4mm) are typically fitted with M4 grounding bolts and lugs.
- How long are the screws in Solar module frame grounding lug?
- The records range from 8 to 12 mm depending on the position, so match each screw to its own hole.
- What is the thread pitch of an M4 screw?
- 0.7 mm (coarse), which is the standard pitch for M4 machine screws; a 0.5 mm fine pitch exists but is uncommon. The tap drill is 3.3 mm and the normal clearance hole is 4.5 mm.
- What screwdriver do I need for Solar module frame grounding lug?
- The sources do not name the drive. For M4, Phillips heads normally take PH2 and Torx heads T20; socket heads take a 3 mm hex key.
- Can I use an imperial screw instead of M4?
- No. Imperial look-alike: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same. Use a true M4 screw so it does not cross-thread or strip the hole.