AC Level 2 EV Charger electrical wiring
Canada/USA residential voltage is 120-240 volts
Commercial/industrial buildings voltage is usually 120-208 volts
(Consult local electrical codes for actual requirements)
|Circuit Breaker (240V double-pole)
|Wire size, copper, AWG
|EV Charger (continuous output)
|Power @ 208 volts
|Power @ 240 volts
|6 see ampacity table
|40 amps (see this graphics)
|8 see ampacity table
|30 amps (see this graphics)
Continuous load such as EV charging should only draw 80% of
the circuit breaker's rating to avoid overheating and tripping.
You can buy Level 2 "EV chargers" (technically
speaking, these are EVSE Electrical Vehicle Supply Equipment) from
manufacturers such as https://www.clippercreek.com/
, car dealers, BestBuy, Amazon, Walmart, Costco etc. EVSE act like
an expensive interface/safety device to protect (1) the wiring
(overloads, overheat, fire), (2) personnel (electric shock, electric
burns) and (3) vehicle on-board circuits (communications). The
actual charging circuit is inside the vehicle called On-Board
Charging Module (OBCM).
An important parameter (4th column in Table 2) is the vehicle's AC
charging "Acceptance Rate" (kilowatts) which sets the upper
limit of charging. J1772 AC Level 2 charging allows up to 19.2
kilowatts of power delivery (240 volts @ 80 amps).
DC charging (Level 1 DC and Level 2 DC) has much higher power
ratings but it is not the subject of this article.
Many Level 2 chargers sold at big-box stores are 32 amps
(7.7 kW @ 240 volts or 6.6 kW @ 208 volts).
Typical public charging stations at libraries, city halls, shopping
malls, etc are 6.6 kilowatts or 6.0 kilowatts
(2019) If you have a 32 amps EVSE at home (7.7 kW @ 240
volts), one hour of charging time at home will give
these approximate range:
Tesla Model 3 SR+ (7.7 kWh): 51 km. Nissan Leaf (6.6 kWh): 35 km.
Chrysler Pacifica PHEV (6.6 kWh): 21 km.
Hyundai Sonata PHEV 9.8 kWh battery (3.3 kWh in 1 hour) 15 km [due
to 3.3 kW acceptance rate].
(2019) If you opt for a 40 amps EVSE at home (9.6 kW @ 240
volts), one hour of charging time at home will give these
Tesla Model 3 SR+ (9.6 kWh): 64 km.
Nissan Leaf, Chrysler Pacifica PHEV ranges are the same as a 32 amps
charger because the respective vehicle's Acceptance Rates are
already maxed out.
(2019) Opting for a 40 amps EVSE at home for Nissan Leaf,
Chrysler Pacifica, etc. does not speed up charging except it
provides a potential for future vehicles with higher AC charging
The many different
electrical plugs used by 240 volts EV chargers are
very confusing. EVSE manufacturers seem to converge on the NEMA type
14-50 plug and NEMA 14-50R
receptacles (up to 50 amps). Or, you can choose a "hardwired"
version when you buy your EVSE.
If I have a 30A circuit and a 24A EV charger, can I plug in a
Chrysler Pacifica PHEV? Yes, the charging current is set at 24A.
If I have a 40A circuit and a 32A EV charger, can I plug in a
Chrysler Pacifica PHEV? Yes, the Chrysler Pacifica can accept 27.5A.
If I have a 30A circuit and a 32A EV charger, can I plug in a
Hyundai Sonata PHEV? Yes, Sonata will charge at 14A. But there is a
problem with this installation: if someone plugs in a Tesla Model 3,
the EV Charger will deliver 32A to the Tesla. In this scenario, the
30A circuit breaker will trip within seconds (or minutes) because an
overload condition occurs (drawing 32 amps on a 30 amp
Solutions to above problem: (1) Replace the 32A charger by a 16A or
24A charger or (2) Keep the 32A EV charger but upgrade the wiring
from 30A to 40A: Use a 40A circuit breaker and replace the #10AWG
wires by #8AWG wires.
© 2019 Nicholas Fong
SMS 短信 778.385.4366
Last updated: 2019-11-16