New Electrical Code Could Doom Most Common EV Charging

Re:New Electrical Code Could Doom Most Common EV Charging by Workaccount2 on Friday January 24, 2025 @10:58AM (#42814361)

My guess is that it is likely from Y caps filtering common-mode noise. They are great for filtering EMI to pass strict emissions regs, so it is easy to use them liberally.

I'll admit I don't know what kind of currents they see, but 5mA on transients wouldn't be particularly surprising. There is also the factor of how sensitive the GFCI is.

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Re:New Electrical Code Could Doom Most Common EV Charging by photon_rancher on Friday January 24, 2025 @12:12PM (#42815202)

Over 100nF of unbalanced Y-caps is needed at 60Hz/120V to see 5mA gnd current. That would be a big Y capacitor (2.2n or lower is common) and they’re usually used in a balanced configuration which would reduce it further. If a Y capacitor fails on one leg, you have a problem. If a Y capacitor fails is only present on one leg, you have a problem.

And if it’s resistive leakage, that’s almost a watt of dissipation - also huge and probably a short in a cable and potentially a fire risk.

5mA is a massive threshold for well designed devices

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Re:New Electrical Code Could Doom Most Common EV Charging by Workaccount2 on Friday January 24, 2025 @03:25PM (#42816592)

It would be fast transients that are in the kHz to MHz and over 120V. Thats why I wonder about the sensitivity of the GCFI. Can it tolerate 5mA for 50ns?

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Re:New Electrical Code Could Doom Most Common EV Charging by atoav on Saturday January 25, 2025 @06:08AM (#42820935)

It should, typically trip times should be in the single digit miliseconds range (the idea is to stop within half of a 60/50Hz cycle).

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