On 8/8/2023 9:27 AM, Lasse Langwadt Christensen wrote:>> So, YOU have decided that the internal GFCI is not needed? >> >> Why not contact the manufacturer and ask them why they >> designed a product that in 99% of usage models WILL >> be connected to a GFCI yet trips unexpectedly? Clearly, >> someone didn't understand their application! > > his "charger" is probably a pile of random electronic scrap held > together with zipties and chewing gumProlly. :< Or, a dozen tiny $5 chargers working in parallel... People forget that wire isn't just "wire". And that outlets (receptacles) aren't just "connection points". I had a helluva time getting the branch circuit that feeds the outdoor outlets along the back of the house to be "stable" (powers the XMAS lights that we use on the citrus trees). Prolly 120 ft from the load center with loads (albeit small) -- each ~75 ft long (strings of 9W bulbs) -- on the end of 100 ft extension cords. I seriously reconsidered running the power DIRECTLY out to the individual trees, below grade. But, the idea of outlets poking up out of the soil was really visually unappealing. OTOH, the outlets in the garage are *technically* at ceiling level and don't require such protection. *But*, I've installed retractable coil reels at each so you can pull an outlet down to use it -- too bad, so sad if you're short! :> (accessing the outlets along the wall is impractical as we have floor to ceiling shelving, throughout). So, my own "best interests" suggested putting that branch circuit on GFCI, too! [ObTrivia: The length of a claw hammer's handle is a good yardstick for locating wall outlets above the floor level! (easy enough to verify before employing as such] [[And, of course, there's the inevitable "smiley face up vs. smiley face down" argument! :> ]]
EV charging on GFCI
Started by ●August 6, 2023
Reply by ●August 8, 20232023-08-08
Reply by ●August 8, 20232023-08-08
On 8/8/2023 10:40 AM, Buzz McCool wrote:> On 8/8/2023 9:40 AM, Don Y wrote: >> ... so, the outlet that typ powers your garage door opener need not be >> GFCI-protected. > > Very interesting. I'm going to see if that's the case in my garage. Thanks Don!Often, they just tack it onto the lighting circuit for the garage as the motor is a relatively small load.
Reply by ●August 8, 20232023-08-08
On 8/8/2023 12:35 PM, Ricky wrote: <snip>> My understanding is the GFCI is just a toroid with both power leads wound through it so that is is sensitive to the difference in current only. This is sensed by an amplifier and used to control a relay. I can't see how cascading these would cause any problem. >That is the essence, but it's a bit more complex than that. A GFCI detects a difference (of about 5ma or more) in current between the line conductor and the neutral conductor as you described. It also can detect a neutral to ground short on the load side, if one exists. See page 6 of the datasheet: https://media.digikey.com/pdf/Data%20Sheets/Texas%20Instruments%20PDFs/LM1851.pdf I don't know if that applies to all GFCI's - I suspect it does. And I don't know if is a factor in the EV charging problem discussed in the thread. Ed
Reply by ●August 8, 20232023-08-08
I'm aware of a similar situation. Using Pentair pool pumps requires using one and only one brand of GFI breaker. I believe it's a Siemons; I know Square-D's will keep tripping. -- A host is a host from coast to coast...............wb8foz@panix.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
Reply by ●August 8, 20232023-08-08
On Tuesday, August 8, 2023 at 5:59:01 PM UTC-4, ehsjr wrote:> On 8/8/2023 12:35 PM, Ricky wrote: > > <snip> > > My understanding is the GFCI is just a toroid with both power leads wound through it so that is is sensitive to the difference in current only. This is sensed by an amplifier and used to control a relay. I can't see how cascading these would cause any problem. > > > That is the essence, but it's a bit more complex than that. > A GFCI detects a difference (of about 5ma or more) in current > between the line conductor and the neutral conductor as you > described. It also can detect a neutral to ground short on the > load side, if one exists. See page 6 of the datasheet: > https://media.digikey.com/pdf/Data%20Sheets/Texas%20Instruments%20PDFs/LM1851.pdf > > I don't know if that applies to all GFCI's - I suspect it does. > And I don't know if is a factor in the EV charging problem > discussed in the thread.I have dug around for a long time, looking for an answer about the cause of this problem and I have yet to find one. The worst sources seem to be the people who install them. One electrician has a document on his web site, where he claims 60% of such devices will fail when used in tandem. That seems rather high, given that the vast majority of EVSEs installed to an outlet, will have such a double GFCI. If it were true that they fail in 60% of installations, this would be a more widely known issue, with a well known solution. I found a discussion on a Tesla forum where is it claimed that replacing the upstream GFCI virtually always fixes the problem. I would not be inclined to forego the GFCI on any receptacle. It saves lives. That's why it's in the NEMA code. They continue to look at how people are injured and die, and find ways to prevent those deaths. Some people think they know better, so are happy to ignore what the experts say. It will be too bad, when Ed fries himself, and there is no video of it. -- Rick C. --- Get 1,000 miles of free Supercharging --- Tesla referral code - https://ts.la/richard11209
Reply by ●August 9, 20232023-08-09
On Tue, 8 Aug 2023 09:35:37 -0700 (PDT), Eddy Lee <eddy711lee@gmail.com> wrote:>On Tuesday, August 8, 2023 at 9:34:12?AM UTC-7, Lasse Langwadt Christensen wrote: >> tirsdag den 8. august 2023 kl. 18.32.35 UTC+2 skrev Eddy Lee: >> > On Tuesday, August 8, 2023 at 9:27:15?AM UTC-7, Lasse Langwadt Christensen wrote: >> > > tirsdag den 8. august 2023 kl. 18.23.31 UTC+2 skrev Don Y: >> > > > On 8/8/2023 9:15 AM, Eddy Lee wrote: >> > > > > On Tuesday, August 8, 2023 at 9:06:41?AM UTC-7, Don Y wrote: >> > > > >> On 8/8/2023 8:25 AM, Eddy Lee wrote: >> > > > >>> On Tuesday, August 8, 2023 at 1:10:48?AM UTC-7, Don Y wrote: >> > > > >>>> On 8/7/2023 6:35 AM, Eddy Lee wrote: >> > > > >>>>> On Monday, August 7, 2023 at 12:42:42?AM UTC-7, upsid...@downunder.com wrote: >> > > > >>>>>> On Sun, 6 Aug 2023 19:51:49 -0700 (PDT), Eddy Lee >> > > > >>>>>> <eddy7...@gmail.com> wrote: >> > > > >>>>>> >> > > > >>>>>>> I am using the portable charger on friend's house, but it's tripping the GFCI circuit. How is that possible if the vehicle is isolated from the ground with four rubber tires? >> > > > >>>>>> Is the charger connected to a grounded mains socket ? Any current >> > > > >>>>>> leaking from the L to PE can cause CFCI problems. You do not need a >> > > > >>>>>> direct physical leakage to surrounding ground. >> > > > >>>>> >> > > > >>>>> Yes, would it be better not to connect the ground wire? >> > > > >>>> Yeah, silly third wire no doubt put there just to allow >> > > > >>>> electricians to charge more for each fixture they install. >> > > > >>>> Likewise, those pesky *fuses*! >> > > > >>>> >> > > > >>>> The GFCI is telling you something. Why not *listen*? >> > > > >>> >> > > > >>> Q: WHAT�S THE PROBLEM with outlets on GFCI breakers � aside from cost? >> > > > >>> A: About 60% of the time, we find that EV chargers WILL NOT WORK on a GFCI breaker (true of >> > > > >>> both wall mount and �mobile connectors�). In those cases, when an EV charger is plugged in, >> > > > >>> the breaker trips (and won�t reset with the unit plugged in). This is because all EVSE already >> > > > >>> have GFCI technology built-in, and the two devices (GFCI breaker and GFCI charger) don�t play >> > > > >>> well together. This is an extreme version of the problem known as �nuisance tripping.� >> > > > >>> >> > > > >>> https://www.williamselectric.net/documents/FAQs-NEMA-1450-outlets-pkg-20210919.pdf >> > > > >> Duh. You aren't supposed to cascade GFCI's. (And, actually, AFCI's are >> > > > >> now the new norm) >> > > > >> >> > > > >> The fact that the folks designing the chargers haven't realized that >> > > > >> ALL OUTDOOR/GARAGE OUTLETS ARE EXPECTED TO BE GFCI PROTECTED and >> > > > >> designed their chargers accordingly sure seems like a colossal fuckup! >> > > > >> >> > > > >> Remove the GFCI from your garage. Then, wait to get electrocuted when >> > > > >> you plug in your vacuum cleaner to finish cleaning the car you just >> > > > >> washed. Ooops! (Maybe you should plug your charger into a BEDROOM outlet, >> > > > >> instead?) >> > > > >> >> > > > >> [If you're like us, your GFCI protection is in the load center, NOT >> > > > >> the outlet] >> > > > > >> > > > > Yes, this will come up again in another house. I am going to try to add a switch to by-pass the internal GFCI. >> > > > So, YOU have decided that the internal GFCI is not needed? >> > > > >> > > > Why not contact the manufacturer and ask them why they >> > > > designed a product that in 99% of usage models WILL >> > > > be connected to a GFCI yet trips unexpectedly? Clearly, >> > > > someone didn't understand their application! >> > > his "charger" is probably a pile of random electronic scrap held together with zipties and chewing gum >> > No, it's a commercial sealed unit. You think i would bother with GFCI if I put scraps together?Is it made in China or some other exotic places ? They all know how to seal units so that the user can not check how bad the circuit is :-)>> isn't it the GFCI in the house that trips?What is the tripping current for the in-house GFCI ? 5 mA or 30 mA ? If the charger was originally designed for 30 mA GFCI, the mains EMC filters might have too large capacitors from L to PE and thus the leakage is too large. It is also possible that the manufacturer did not pass the EMC test and simply added the capacitor values to pass the test. Passing the test without tripping the GFCI might mean that an inductor or two had to be added to the mains filter, but that might be too expensive :-).>Yes, because the GFCI in the charger is leaking.Why would the GFCI leak ? Does it have a "TEST" button ? Pressing this button will connect a largish resistor from L to PE and trip the charger GFCI. If pressing the in-house GFCI but not the charger GFCI, the in-house GFCI is more sensitive (5 mA?) than the charger GFCI (30 mA?).
Reply by ●August 9, 20232023-08-09
On 8/9/2023 2:11 AM, upsidedown@downunder.com wrote:> Why would the GFCI leak ? > > Does it have a "TEST" button ? Pressing this button will connect a > largish resistor from L to PE and trip the charger GFCI. If pressing > the in-house GFCI but not the charger GFCI, the in-house GFCI is more > sensitive (5 mA?) than the charger GFCI (30 mA?).GFCIs, in the US, are intended to trip on a nominal 5mA load imbalance. GFCEs raise that threshold to 30mA. There are several other "applications" with their own specific limits. The Code is constantly changing wrt protection devices as more and more technologies come on line in "proven" ways. E.g., GFCIs were initially only required for protecting underwater lighting in swimming pools. Then, spread to outdoor receptacles, in general... bathrooms, garages, spas/jacuzzi, basements, sink-adjacent, countertops, drinking fountains, etc. The same sort of proliferation is now taking place with AFCIs [There have recently been code changes that required them on 240V circuits "near" sinks -- which typically means electric stoves/ovens. AFAICT, this is under review as those tend to have nuisance trips.] The problem with GFCIs is they tend to be finicky about their installation. Esp GFCI receptacles (which homeowners think themselves capable of installing). And, its too easy for folks to have problems with GFCIs leading to their being "defeated" (or simply not used, negating their intended protections) Here, the local AHJ is... "god", when it comes to these matters. And, usually "protected" in that role. So, if of a particular opinion, then that opinion is "law"! [Try asking for a definitive opinion on *where* smoke detectors are *required* -- and PROHIBITED!]
Reply by ●August 9, 20232023-08-09
On Wed, 09 Aug 2023 12:11:20 +0300, upsidedown@downunder.com wrote:>What is the tripping current for the in-house GFCI ? 5 mA or 30 mA ? > >If the charger was originally designed for 30 mA GFCI, the mains EMC >filters might have too large capacitors from L to PE and thus the >leakage is too large. > >It is also possible that the manufacturer did not pass the EMC test >and simply added the capacitor values to pass the test. Passing the >test without tripping the GFCI might mean that an inductor or two had >to be added to the mains filter, but that might be too expensive :-).If you have a 100 nF Y-capacitor (L to PE), on 60 Hz it has a reactance of 27 kohm. Applying 120 V to it and 4.5 mA will flow. If the GFCI nominally trips at 5 mA but consider tolerances in the trip current, capacitance, voltage etc. I would not be surprised if the GFCI sometimes works and sometimes trips. I know that 100 nF is too big for a Y-capacitor and few manufacturers make this big Y-capacitors, but who knows if the charger manufacturer has put multiple smaller in parallel between L and PE :-) to get the EMC values approved.
Reply by ●August 9, 20232023-08-09
tirsdag den 8. august 2023 kl. 22.32.08 UTC+2 skrev Klaus Vestergaard Kragelund:> On 07-08-2023 04:51, Eddy Lee wrote: > > I am using the portable charger on friend's house, but it's tripping the GFCI circuit. How is that possible if the vehicle is isolated from the ground with four rubber tires? > > > > The 15A power extension is fine. I have used this charger on another house before. Is the GFCI outlet too sensitive? > > > > Anyway to deal with this? Temporary bypassing the GFCI outlet? > It's been a long time since I heard of it, but a colleague of mine had > the issue on US mains fed systems feeding inverter drives. AFAIR it was > due to the y capacitor in the drive that was not symmetrical, so when > the inrush control fed current into the DC link capacitor, it would > charge the y capacitors unsymmetric depending on where the turn on was > done on the mains curve.inverter drives sometime have quite few conditions for use with an RCD page 28, https://cache.industry.siemens.com/dl/files/400/24523400/att_33783/v1/420_OPI_24523400_en_1006.pdf
Reply by ●August 10, 20232023-08-10
"Lasse Langwadt Christensen" <langwadt@fonz.dk> schrieb im Newsbeitrag news:85674d6d-84f6-4c33-bfa5-e6c0f191740an@googlegroups.com...> tirsdag den 8. august 2023 kl. 22.32.08 UTC+2 skrev Klaus Vestergaard > Kragelund: >> On 07-08-2023 04:51, Eddy Lee wrote: >> > I am using the portable charger on friend's house, but it's tripping >> > the GFCI circuit. How is that possible if the vehicle is isolated from >> > the ground with four rubber tires? >> > >> > The 15A power extension is fine. I have used this charger on another >> > house before. Is the GFCI outlet too sensitive? >> > >> > Anyway to deal with this? Temporary bypassing the GFCI outlet? >> It's been a long time since I heard of it, but a colleague of mine had >> the issue on US mains fed systems feeding inverter drives. AFAIR it was >> due to the y capacitor in the drive that was not symmetrical, so when >> the inrush control fed current into the DC link capacitor, it would >> charge the y capacitors unsymmetric depending on where the turn on was >> done on the mains curve. > > inverter drives sometime have quite few conditions for use with an RCD > > page 28, > https://cache.industry.siemens.com/dl/files/400/24523400/att_33783/v1/420_OPI_24523400_en_1006.pdf >In our part of EU, ground fault detection has been mandatory for decades. Nowadays, requirements are evolving because users connect new types of loads&equipment to the mains. There are different types of RCD depending on which kind of fault current they detect (also in historical order): Type AC: only detects AC currents, not allowed anymore Type A: also detects pulsed DC; commonly used now, works for most loads Type F: increased frequency range, seldom use, for inverter drives Type B: trips on pure DC currents, too; required for most inverters and EV charging (needed because fault current could be from EV DC voltage) DC current can also prevent correct funtion of the other RCD types by saturating their coil. To guarantee correct operation when cascading RCDs, there are a couple of rules. They result in RCDs with different trip levels, delayed versions and special RCD with low DC trip levels (to make sure upstream RCDs still work).
