Mike, et al, Thanx for mentioning my name; by now you should be able to tell the stories as we’ve talked thru these things before.
From my experience, protection is primarily needed for cord and plug connected equipment where the earthing/grounding is not considered reliable – which includes North America. Most such equipment is allowed to have higher touch current under fault conditions, where the fault current exceeds 5ma the GFCI provides the needed protection Since GFCIs look for the ‘lost to ground current’, the differential current in the power cord, they also work in circumstances where the earth/ground doesn’t exist (a 2-wire installation) or where it should exist but doesn’t. Many are installed in older 2-wire installations because of this in the USA. RCDs rated to trip at 30mA are working right at the c1 Ventricular Fibrillation level of IEC 60479-1 so should provide that protection for most people. Not sure if RCDs are tested or rated for catching performance degradation in machines but you apparently have experience with that. It would be nice to see a paper on that performance feature. North American GFCIs are rated at 5mA which is the letgo-immobilization limit specified in IEC 60479-1. (Yes, I know the allowable range is not trip at 4mA but must trip at 6mA; the rated trip current is still 5mA.) You can still disengage from the current at that level, providing that level of protection. Both North American GFCIs and Euro RCDs are not rated to deal well with high frequency signals generated by Switch Mode Power Supplies and Variable Speed Drives for motors. Lots of ‘nuisance tripping’ results. There is an ongoing UL project to get a handle on this and get it fixed here in NA. Yes, EV chargers are being provided with GFCIs at higher levels, depending upon the installation/application parameters. :>) br, Pete Peter E Perkins, PE Principal Product Safety & Regulatory Affairs Consultant PO Box 1067 Albany, ORe 97321-0413 503/452-1201 IEEE Life Fellow IEEE PSES 2020 Distinguished Lecturer <http://www.researchgate.net/Peter%20Perkins> www.researchgate.net search my name <mailto:p.perk...@ieee.org> p.perk...@ieee.org Entropy ain’t what it used to be From: MIKE SHERMAN <msherma...@comcast.net> Sent: Thursday, February 3, 2022 12:48 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Machinery Leakage Current Doug -- Thanks for mentioning this! Yes, I've seen these 30 mA RCDs or RCCBs before, but not an RCBO (confused? Google can explain these acronyms). I've even recommended these for large machinery. The ones we used had adjustable trip points up to 30 mA. Note that I recommended these for MACHINE protection, not PERSONAL protection. The theory was to monitor potential breakdown of the dielectric of the machine by watching the ground leakage current. As I recall, early on we found, before it failed completely, a variable speed fan drive motor with bridged dielectric that was grounding out through a shaft bearing. I'd love to hear what PETE PERKINS has to say about this! Personally, given that North American GFCIs for 120 VAC have trip points of 4-6 mA, I've tended to not like to exceed that number. As I recall, Pete has demonstrated that even 5 mA will be a current to remember if you conduct it. That said, I think Pete told me a while back that the NEC is raising the allowable leakage current for EV chargers to something quite above 5 mA. I'm sure there's a good story behind that. Note also that GFCIs, and as I recall the RCD we were using, could fail silently and thus needed to be tested regularly to ensure continued protection. Mike Sherman On 02/03/2022 8:23 AM Doug Nix <d...@ieee.org <mailto:d...@ieee.org> > wrote: Hi Mark, I’ve seen mains filters used for 400 V 3 ph. 200A services with leakage currents close to 30 mA. Consider that RCBOs commonly used outside North America have a design trip current of 30 mA, so leakage currents above 30 mA will cause the RCBO to trip. None the less, these large leakage currents can be startling the first time you see them “in the wild”. Doug Nix d...@ieee.org <mailto:d...@ieee.org> +1 (519) 729-5704 On 1-Feb-22, at 13:24, Stultz, Mark <00000f79f2e10e47-dmarc-requ...@listserv.ieee.org <mailto:00000f79f2e10e47-dmarc-requ...@listserv.ieee.org> > wrote: Hello, Is there a hard limit for leakage current for machinery in the EU? IEC 60204-1 provides instructions in clause 8.2.8 for “equipment having earth leakage currents higher than 10 mA”. This seems quite high so we have applied the 3.5 mA limits for class 1 stationary equipment in IEC 60335-1. Is there another source for leakage current limits that is machinery-specific? There is nothing in the type-C standard for this product type. Thanks, Mark Stultz - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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