Rainstorm Day: 7kW Charging Station Motherboard Instant Power Cut? 300mA Leakage Protection vs 6mA National Standard, Which is More Troublesome?

On rainy days, the "instant power cut-off" of 7kW charging piles is not due to motherboard malfunctions but a new national standard that makes leakage protection function like a "chip-level reflex"—0.1ms hardware loop closure + 6mA trip current, which cuts power immediately when rainwater conducts electricity, achieving 50 times the sensitivity of the old 300mA scheme. Below, three paragraphs will clarify "who suffers more" and "how to avoid pitfalls.".

① Protection threshold: 300mA → 6mA, three-stage jump

• Old regulations/generator: 300mA for fire prevention, almost imperceptible to humans—8mA rain current it ignores, allowing users to continue charging until the water film breaks down → arc → trip the generator.

• New National Standard Mainboard: Mandatory Type A 30mA + Optional 6mA DC, with built-in fluxgate chip (RCMU101SN-E), triggering at 1mA DC current, 0.1s hardware cut-off—Rain curtain 8mA instantaneous trip to prevent 750V arc flash.

② 0.1ms hardware closed-loop, 100 times faster than a human blink

• Comparator + Fluxgate Hard Path, No MCU Involvement; The greater the rainfall, the larger the conductive area of the water film, leading to an exponential increase in leakage current. The motherboard powers off during the "human body has not yet perceived" stage—this is the truth behind "instant power-off.".

③ Balanced Approach: Sensitive but Not "Socially Awkward"

• Gradual power reduction: reduce power first during light rain → cut off charging in heavy rain, resulting in "slower charging" rather than "no charging" for users;

• Rain sensor probe: External capacitive rain sensor on the motherboard activates at rainfall >2mm/h, with a 6mA setting (normally 30mA), improving utilization by 12%;

• Resume from Breakpoint: After a trip, the motherboard's buffer retains power, and automatically resets when the rain stops, eliminating the need for users to rescan.

One-sentence conclusion

The old 300mA scheme was "reluctant"—tripping only when the rain film breakdown occurred, posing high risks; while the new 6mA national standard is "sensitive"—tripping immediately upon rain film formation, ensuring high safety. Through graded derating and rain-sensing probes, the new motherboard maintains an availability rate of over 99%, allowing worry-free charging in rainy weather—just avoid plugging or unplugging the charger while standing in water.

Xinrong Technology's 7KW New National Standard AC Charging Pile Mainboard, "Chip-Level Conditional Reflex" – 0.1ms Hardware Closed Loop + 6mA Trip Current, instantly trips when rainwater conducts electricity, safe and reliable. Welcome to inquire and purchase!