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Does charger need a grounded outlet?

Discussion in 'Prime Main Forum (2017-2022)' started by eegah, Nov 22, 2017.

  1. priuscatprimeguy

    priuscatprimeguy Senior Member

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    That's HOT-HOT-HOT ( humming a few bars):p
     
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  2. PT Guy

    PT Guy Senior Member

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    Only if all the wiring in the circuit is correctly installed and connected.
    Huh? The purpose of the circuit breaker is to protect the wire. I guess the 30 amp 120 volt #10 gauge wire could go to a sub-panel in the garage where it splits to two 15 amp #14 circuits. I'd run two 20 amp 120 volt #12 circuits if you have room in the panel. Your electrician will know the best way to proceed with what you have. Especially in a garage, you can control the load by what you choose to run at one time. If you have another heavy load running, just unplug the car charger first, then plug it back in when you're finished with your compressor or saw or whatever.
     
  3. I'mJp

    I'mJp Senior Member

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    If you are charging with a L2 charger, there is no neutral or ground involved with the car.

    But, if the plug were wet and provided a conductive path to the handle and the floor conductive, the charge handle could probably fry you to a crisp, all the while happily charging the car.

    With a properly installed GFCI, the current imbalance would be detected in milliseconds, and the circuit shut off. You could still die, but no smoke or burning.
     
  4. Elektroingenieur

    Elektroingenieur Senior Member

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    In a typical 240-volt home installation, the charging current flows between two ungrounded (hot) conductors, rather than between an ungrounded (hot) conductor and a grounded (neutral) conductor, but the equipment grounding conductor (green wire) is still required. While charging, the Prius Prime is like any other electrical appliance with a grounded metal enclosure.

    The SAE J1772 (FEB2016) standard requires an equipment ground contact on the charging coupler, and Toyota’s Electrical Wiring Diagram for the Prius Prime (EM32D0U) shows how this is connected to body (chassis) ground on the car via Ground Point hA. This is connection is essential; as J1772 states (in 4.2.1.3.8):
     
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  5. eegah

    eegah Member

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    Yeah, I realized what a stupid idea that was shortly after I wrote it. Our panel is full, but one of the 20A circuits is connected to a single outlet that the previous owner used for a freezer. That could certainly be re-purposed. However, it turns out one of the outlets on the 15A garage circuit (that happens to be on the house side, so I missed it before) reported that it had ground connected, so I may be able to just add a new outlet with ground or fix one of the existing ones. If I have to ramp to car down to the 8A charge setting to prevent a breaker trip, no huge deal. I'd rather do that than spend a few hundred running a new circuit.
     
  6. Old Bear

    Old Bear Senior Member

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    I totally agree with Kevin. His explanation is spot on.

    In older houses, where there may not be a ground present at the outlet box, an accepted work-around is to install a GFCI device, typically a GFCI outlet.

    Eegah began this thread by noting that he had an older house and that his electrician had installed a GFCI outlet in his garage because there was no ground wire (or grounded conduit, armored cable, etc.) present.

    I learned from my electrician when he installed my L2 EVSE device, that he used a basic 50A circuit breaker because the EVSE was permanently wired into the circuit. Had the EVSE been on a plug (using a typical 14-50R 240-volt outlet), he would have had to use an expensive GFCI circuit breaker. Although the EVSE contains its own GFCI protection, if it were connected by a plug, there is no guarantee that someone might inadvertently make contact with the wiring while unplugging it or using the outlet for some other piece of equipment.

     
  7. eegah

    eegah Member

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    That's a bit disturbing to hear. My electrician put a basic breaker with a 14-50 plug.
     
  8. Old Bear

    Old Bear Senior Member

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    I am not an expert on the National Electrical Code (NEC) which most local jurisdictions use. From what I understand, the NEC requirement is under review and it appears that all outlets in a damp area like a garage, or outdoors, will require GFCI protection. That makes sense, because there's no way to know what might get plugged in -- or whether a person is standing in a puddle clutching a wet cord with wet hands while plugging in anything.

    The EVSE unit will provide built-in GFCI protection for the cable from the EVSE to the car. So, that's not going to be an issue. It's only the connection between the EVSE and the outlet that would benefit from ground fault protection.

    In any case, if your new 14-50R outlet is on its own circuit, it's no big deal to replace the circuit breaker in the distribution panel with a GFCI breaker. I have not checked lately, but I think such a breaker might cost about $80 or so.

    For a very good discussion of this issue, check the conversation in the Tesla users' form: Ground fault protection a new complication for EV charging? | Tesla Motors Club

    Personally, if you've got your 14-50R outlet installed and your local building code enforcement officer has accepted it -- and if you're not planning to be plugging and un-plugging your EVSE unit -- I'd just let it be and not worry about it.
     
  9. Andyprius1

    Andyprius1 Senior Member

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    What does that mean? 120....120.....ground ?
     
  10. Prodigyplace

    Prodigyplace Senior Member

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    There is 240 volts between the 2 HOT wires. Each HOT wires is also 120 volts to the (unused) Neutral wire. @jerrymildred used to be an electrician, IIRC. Perhaps he can explain it better.

    The charger requires 240 volts like an electric range, heat pump, & electric dryer require. My well pump is also 240 volt.
     
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  11. Elektroingenieur

    Elektroingenieur Senior Member

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    The review is done: the requirements for GFCI protection of receptacle outlets were expanded in the 2017 NEC. The 2014 NEC requires (with some exceptions) only 15- and 20-ampere receptacles to have GFCI protection, but the 2017 NEC requires receptacles up to 50 amperes to be protected, in certain circumstances. Compare 210.8 in the two editions, and also see the new 625.54 in the 2017 NEC:
    Note that I’m describing the NEC as published by the National Fire Protection Association, not as adopted or amended in any particular jurisdiction. For example, California adopted the 2014 NEC, with amendments, effective January 1, 2017; requirements from the 2017 NEC are unlikely to apply here before 2020.
    I haven’t seen your installation and don’t know your local code, so I can’t recommend that you should have, or not have, a GFCI circuit breaker. The code-making panel presumably thought the additional protection was worth the cost. If the outlet is in a dry location and, as @Old Bear mentions, the charging equipment won’t be connected or disconnected frequently, and the installation has already been accepted by an inspector, it may not be cost-effective to replace the circuit breaker.
     
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  12. fuzzy1

    fuzzy1 Senior Member

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    Think of it a positive 120 and a negative 120, so the difference is 240. Don't ask which is positive and which is negative, that alternates every few milliseconds.

    That is how split-phase 120-240 works. Appliances that need both 240 and 120 for different internal circuits (e.g. kitchen ranges) must have a neutral wire for the 120 portions. Appliances that need only 240, not 120, (e.g. water heaters, baseboard heaters) can drop the neutral wire,
     
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  13. Andyprius1

    Andyprius1 Senior Member

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    TY So you are speaking of the small white wire, as the neutral?
     
  14. Old Bear

    Old Bear Senior Member

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    This illustration and diagram may help:


    (Note that the ground contact is located at the top of the outlet. For odd, historical reasons, in the U.S. most outlets, including ordinary 120 volt outlets, are mounted with the ground at the bottom... i.e., upside down. If you look at outlets in most hospitals and medical facilities, outlets are installed with the ground at the top which is the correct standard. But, if you do that in your kitchen at home, it's likely that your spouse will think you're crazy. It becomes more important with the 14-50R outlet because many EVSE devices with factory-installed cords follow the ground-at-top standard and hence are easier to connect if the outlet is installed with the ground at top.)

    For example:

    JuiceBox-EVSE.jpg
     
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  15. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    The 32A Chargepoint home charger uses a NEMA 6-50 plug, which does not have Neutral. Alternatively, one can get the 32A charging station as hard wired (NO plug).
     
  16. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    In our house built about 6 years ago, the 120V outlets that are controlled by a wall switch have the ground pin on top. The others have the ground pin on the bottom. Took me a while to figure that out, but it is 100% consistent in our house.
     
  17. Lee Jay

    Lee Jay Senior Member

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    Same as mine built 20 years ago.
     
  18. Old Bear

    Old Bear Senior Member

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    Some 240-volt devices also use 120-volts. For example, an electric range with a 240-volt heating elements and a 120-volt light bulb in the oven. Hence the three-wire plus ground on NEMA 14-50R and similar four-prong appliance outlets.

    Other devices, such as many EVSE units, only use 220-volts and can be served by two wires plus ground.

    My Leviton EVR-40 uses only 220-volts and was installed "hard-wired" so that choice of outlet was not a concern. However, because the number and size of the wires run inside electrical conduit determines what diameter conduit must be used, running only two wires plus ground also saved cost.

    Even if you're not using conduit, two-conductor plus ground cable will cost less per foot that three-conductor plus ground. Of course, the bigger part of your cost is the electrician's time and labor -- but saving money on materials is is still desirable.
     
  19. fuzzy1

    fuzzy1 Senior Member

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    The neutral generally should be white, but that doesn't mean the white is always neutral. E.g. if a 240V circuit has black-red-white, the white is supposed to be the neutral. But if the 240V circuit has just black-white (no red), then both are likely hot.

    I.e. between exceptions and errors, don't mistake my response as any assurance that white is always neutral.
     
  20. Old Bear

    Old Bear Senior Member

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    That's correct. It's also why the white wire should be clearly marked with red color-coding tape at each end -- but more frequently than not, the electrician doesn't bother to do this.

     
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