GerryAZ
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 6:27 am

National standards do not require ground fault circuit interrupter (GFCI) breakers for 50-ampere, 240-volt receptacles (local codes may be more stringent). All 15- or 20-ampere, 240-volt receptacles installed in garages or outdoors should be protected by GFCI breakers since they could be used for air compressors, power tools, or other cord and plug-connected equipment. EVSEs that comply with national codes and standards have internal ground fault protection and their supply cords are a maximum of 12 inches in length so you should have your EVSE available and determine the mounting location before installing a new receptacle for it. Follow branch circuit requirements noted in the EVSE installation instructions.

Some 30-ampere (or higher), 240-volt EVSEs which are intended for permanent mounting (whether plug-connected or hard-wired such as the AeroVironment unit I purchased in 2011) will trip standard GFCI breakers because they pass a small leakage current as a method to test the equipment ground connection. I had to replace a GFCI breaker with a standard 40-ampere breaker to use my AeroVironment EVSE. Any EVSE that is truly intended to be portable should be suitable for use with a receptacle that matches its plug protected by a GFCI breaker of appropriate current rating.
Last edited by GerryAZ on Sat May 12, 2018 10:31 am, edited 1 time in total.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

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EVDRIVER
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 8:12 am

GerryAZ wrote:Building codes do not require ground fault circuit interrupter (GFCI) breakers for 50-ampere, 240-volt receptacles. All 15- or 20-ampere, 240-volt receptacles installed in garages or outdoors should be protected by GFCI breakers since they could be used for air compressors, power tools, or other cord and plug-connected equipment. EVSEs that comply with national codes and standards have internal ground fault protection and their supply cords are a maximum of 12 inches in length so you should have your EVSE available and determine the mounting location before installing a new receptacle for it.

Some 30-ampere (or higher), 240-volt EVSEs which are intended for permanent mounting (whether plug-connected or hard-wired such as the AeroVironment unit I purchased in 2011) will trip GFCI breakers because they pass a small leakage current as a method to test the equipment ground connection. I had to replace a GFCI breaker with a standard 40-ampere breaker to use my AeroVironment EVSE. Any EVSE that is truly intended to be portable should be suitable for use with a receptacle that matches its plug protected by a GFCI breaker of appropriate current rating.


So you are familiar with all local building codes in all US cities? Have you been on many inspections with local inspectors and seen the type of crazy things they require on outside and garage outlets ? Not to mention some local arc fault requirements. I've experienced far too many painful experiences on inspections not based on reason.
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smkettner
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 8:27 am

Get a permit and related inspection. Then you know.
1 bar lost at 21,451 miles, 16 months.
2 bar lost at 35,339 miles, 25 months.
LEAF traded at 45,400 miles for a RAV4-EV

GerryAZ
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 10:43 am

EVDRIVER and smkettner,

Thanks for calling me out on the misleading statement. I have edited my earlier post to avoid misleading anyone. GFCI breakers provide additional safety if the equipment being installed is compatible. Unfortunately, there are some 240-volt EVSEs that are not compatible with standard GFCI 2-pole breakers.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

MikeD
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 1:57 pm

Is a dedicated hard wired EVSE circuit w/ a GFCI breaker significantly safer than one w/o? If not for shock protection, what about for fire prevention?

smkettner
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 2:27 pm

MikeD wrote:Is a dedicated hard wired EVSE circuit w/ a GFCI breaker significantly safer than one w/o? If not for shock protection, what about for fire prevention?
afaik the EVSE should have GFCI protection already. No need for belt and suspenders IMO.
1 bar lost at 21,451 miles, 16 months.
2 bar lost at 35,339 miles, 25 months.
LEAF traded at 45,400 miles for a RAV4-EV

MikeD
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 5:11 pm

smkettner: It is my understanding that the GFI protection that an EVSE provides is only "downstream" from its control unit and so not at the plug input end (which is "upstream" from the control unit).

Excerpt from the Siemen's Versicharge "Installation and Operations Manual":
"The Siemens VersiCharge line of EV Charging Systems includes a Charging Circuit Interrupting Device (CCID). The CCID is required by UL Standard 2231 and is designed to detect grounding faults within the system [I believe "system" is referring to its EVSE], and disconnect power from the downstream conductors when a fault is detected".

How could an EVSE disconnect power at its input plug end?

So assuming the charging cord remains intact the GF protection is of importance only at the exposed conductors within the J1772 plug -- which should normally be electrically hot only after plugging in/before unplugging from the EV (so normally not directly touchable). Also I believe a typical GFCI allows only about 6ma of current as opposed to usually 20ma of current at the J1772 output end -- i.e. a GFCI stops the duration of voltage shock significantly faster. It is possible that EVSE's have changed in this regard (specs don't always document this issue). I think EVSE manufacturers may be struggling with "nuisance tripping" issues -- an EV owner won't be happy with an EVSE that GF trips frequently -- even if it resets and continues. And some circuit issues that cause sporadic GFs, like insufficient circuit wire insulation integrity that can allow too much current leakage, are beyond the control of the EVSE design.

I just found this additional excerpt"
"Nuisance fault: As a leader in electrical technology, Siemens has made the decision to install 5 mA grounding protection in all VersiCharge devices. This is the same level of protection that is required in kitchens and bathrooms of residential dwellings. Some other manufacturers (EVSE and Auto manufacturers) have selected 20 mA protection levels. Because Siemens units measure to a more sensitive level, occasional charging interruption may occur under certain circumstances."

smkettner
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 5:34 pm

I have no concern of power leakage at the power plug. If plugging in during driving rain with everything soaked just take a bit of extra precaution. Non-issue indoors. Non-issue with hardwired EVSE.
1 bar lost at 21,451 miles, 16 months.
2 bar lost at 35,339 miles, 25 months.
LEAF traded at 45,400 miles for a RAV4-EV

MikeD
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Re: Specs for 240v outlet/breaker

Sat May 12, 2018 7:15 pm

smkettner: Suppose some curious visiting headstrong children unplug that EVSE...?
Suppose you have metal conduit leading to that receptacle -- NEC requires that conduit be grounded. How easy is it to momentarily accidentally touch one of the two (long) hot prongs of a 14-50 plug with the fingers of one hand while resting the other hand on the conduit?
Ever get momentarily dizzy? The odds are small, but multiply that by the tens of millions that I hope trade their ICE cars for EVs soon, so I hope the odds are made to be even smaller.

I am with you on having EVSEs being hardwired if at all possible!

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