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Why does this flying bug UV light trap intermittently trigger my GFCI?
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james_s:

--- Quote from: pcprogrammer on November 19, 2022, 08:12:14 pm ---Wow that is low. Over here 30mA is common and comes in two types, slow and fast. There also used to be a 300mA or even 500mA version for a circuit with a washing machine or other type of inductive load, but not sure if they are still sold. Nowadays the slow type is used for the washing machine.

But which such a low current it must trip rather easily.

--- End quote ---

That's the idea, they're meant to trip easily if for example you pick up the end of an outdoor extension cord with wet hands. They're only used for specific purposes, originally receptacles outdoors, garages and in bathrooms had them mandated by the late 70s, then in the 90s they started requiring them for kitchen receptacles and anything else near a source of water. We don't have the sort of whole house RCDs used in some parts of the world.
tom66:

--- Quote from: james_s on November 19, 2022, 06:55:36 pm ---The OP is in the USA, GFCI trip current is 5mA.

--- End quote ---

I have read though that it's not unusual for such a GFCI to take several seconds to trip at its rated current.

Whereas a 30mA RCD in the EU will trip in less than 40ms.

The result is that while EU RCD will not trip <30mA, both types will trip within a similar amount of time (<100ms) at dangerous current levels (>=30mA, heart fibrillation usually occurs >40mA.)
james_s:

--- Quote from: tom66 on November 19, 2022, 11:51:23 pm ---I have read though that it's not unusual for such a GFCI to take several seconds to trip at its rated current.

Whereas a 30mA RCD in the EU will trip in less than 40ms.

The result is that while EU RCD will not trip <30mA, both types will trip within a similar amount of time (<100ms) at dangerous current levels (>=30mA, heart fibrillation usually occurs >40mA.)

--- End quote ---

I can't say I've ever tested that. I do know from experience though that if you drop the end of an extension cord in a puddle on the ground outside the GFCI will trip instantly. I've never tried to actually measure it but maybe I will sometime if I get bored.
timenutgoblin:

--- Quote from: NeverDie on November 18, 2022, 09:32:29 am ---Attached is an overview photo together with a photo of the circuit board inside.

--- End quote ---

I think this type of circuit likely uses a dedicated LED driver IC and a bridge rectifier - both surface mount type and would need to be located on the back of the circuit board. Maybe it's just a pair of transistors (MOSFET or BJT) configured as a current limiting circuit. One of those electrolytic capacitors is likely to be a high voltage rated type of small capacitance. I can't see a fuse, but the resistor is likely to be a fusible type.

I have seen something similar on BigClive and DiodeGoneWild.
tooki:

--- Quote from: tom66 on November 19, 2022, 11:51:23 pm ---
--- Quote from: james_s on November 19, 2022, 06:55:36 pm ---The OP is in the USA, GFCI trip current is 5mA.

--- End quote ---

I have read though that it's not unusual for such a GFCI to take several seconds to trip at its rated current.

Whereas a 30mA RCD in the EU will trip in less than 40ms.

The result is that while EU RCD will not trip <30mA, both types will trip within a similar amount of time (<100ms) at dangerous current levels (>=30mA, heart fibrillation usually occurs >40mA.)

--- End quote ---
Regulations allow multi-second reaction times for very low current, but in practice they practically always react in a fraction of a second. See e.g. page 6 of https://www.westernautomation.com/wp-content/uploads/2016/03/GFCIs_For_AC_DC_Systems.pdf
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