Skylight cleaning robots should never run during a thunderstorm, and the real risk is not a direct strike. It is induced surge on the tether and static charge on a dry glass surface. Both are manageable with scheduling and one grounding rule.
Lightning is not the first thing facilities managers think about when they buy a glass roof robot, and most of the time that is fine because you clean in daylight in fair weather. The problem is the edge cases: rooftop robots on tall buildings, and winter static in dry climates.
How far away is safe for a rooftop robot?
The common rule for outdoor work is to stop when thunder is within 10 km, and to wait 30 minutes after the last thunder before resuming. For a robot on an exposed roof, treat it the same as any outdoor crew. The robot has no lightning protection, and its tether is a long conductor lying across the glass.
| Situation | Action |
|---|---|
| Storm forecast within 3 h | Do not start a run |
| Thunder within 10 km | Stop, power down, retreat indoors |
| Last thunder < 30 min ago | Wait longer |
| Dry, cold, clear | Watch static, see below |
Is static really a problem on glass roofs?
On dry winter days, a robot dragging a dry brush across large glass can build up a significant charge, and the first thing the operator notices is a small shock when disconnecting the tether. That is annoying, not dangerous. What matters is that the charge finds a path through the control box, which is why grounding the chassis before disconnecting is worth the five seconds it takes.
Keep the tether connector away from your body when you unplug. Wear non-slip gloves. Both are cheap habits.
What does this mean for scheduling?
Build weather windows into the contract, not just dates. A monsoon or summer storm region should schedule roof work in the morning and keep afternoons flexible. The Lingfeng S1 is light enough to recover quickly when a run is cut short, which is why it suits regions with unstable afternoon weather.
If your building has a rooftop lightning protection system, do not tie the robot tether or control box to it. That is not grounding, that is giving a surge a path to your electronics. Use a proper building ground point or a dedicated earth rod, and ask the building engineer before you assume one exists. For site-specific advice, get in touch.
Key Takeaways
- Stop outdoor robot work when thunder is within 10 km.
- Wait 30 minutes after the last thunder before resuming.
- Never bond the robot to the building lightning protection system.
- Ground the chassis before disconnecting in dry, cold weather.
- Schedule flexible morning windows in storm regions.