Circuits
The best EV chargers for a 40-amp circuit
A 40-amp circuit is one of the most common EV installs, and it is plenty for most drivers -- as long as the charger on it is set to 32 amps.
By Sawyer V. · Published September 10, 2026
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The biggest charger is rarely the right one. A 40-amp circuit uses thinner wire and a smaller breaker than the 60 amps a 48-amp charger needs, it fits many more panels, and 32 amps of charging covers far more than a typical day's driving overnight.
Picks for a 40-amp circuit
Ranked for a first home charger. Every row jumps to the full write-up below.
| # | Product | Best for | Max output | Price |
|---|---|---|---|---|
| 1 | ChargePoint Home FlexHomes with an uncertain panel. J1772, 23 ft cable. | Homes with an uncertain panel | 50 A12 kW | Check price on Amazon#ad how we are funded |
| 2 | Grizzl-E ClassicHarsh weather and no app. J1772, 24 ft cable. | Harsh weather and no app | 40 A9.6 kW | Check price on Amazon#ad how we are funded |
| 3 | J+ Booster 2The best portable overall. J1772, 25 ft cable. | The best portable overall | 40 A9.6 kW | Check price on Amazon#ad how we are funded |
What 40 amps gives you
A 40 A circuit
The code limits a continuous load to 80% of its circuit: 40 x 0.8 = 32 A
32 A x 240 V = 7.7 kW
At 3.5 mi/kWh, about 27 miles of range per hour
Over a ten-hour night, about 270 miles
Setting the charger
A charger that can draw more than 32 A has to be set to 32 A for this circuit. The ChargePoint Home Flex has a 32 A setting among its six; the Grizzl-E Classic can be set to 16, 24, 32 or 40 A; the J+ Booster 2 portable offers 32 A among its settings, and on a portable you choose it yourself each time you plug in. Label the circuit so the next person knows. How many amps you need.
The receptacle question
NEC Table 210.21(B)(3) permits a 40 or 50 A receptacle on a 40 A circuit, and 40 A receptacles are rare -- so a plug-in install here usually means a NEMA 14-50 on a 40 A breaker. The rule that keeps it safe is the setting: anything plugged into that receptacle must be set to 32 A or less. A receptacle for a charger generally needs ground-fault protection under current code; your electrician fits what your jurisdiction requires. NEMA 14-50 outlets.
The picks in detail
Two wall units and a portable, all with a 32 A setting, each with the case against it.
1. Homes with an uncertain panel
ChargePoint Home Flex
ChargePoint · J1772 · 50 A / 12 kW · 23 ft cable
The most adjustable unit here. It can be set anywhere from 16 A to 50 A, which makes it the one to buy when you do not yet know what your panel will allow.
What is good
- Six selectable amperage settings from 16 A to 50 A
- Sold in both hardwired and NEMA 14-50 versions
- Rated for indoor or outdoor installation
- The app is mature and does not require a subscription
What is not
- 23 ft is a foot shorter than the longest cables in this group
- The 50 A setting needs a bigger circuit than most panels have spare
| Maximum output | 50 A / 12 kW at 240 V |
|---|---|
| Amperage settings | 16, 24, 32, 40, 48 or 50 A |
| Connector | SAE J1772 |
| Cable | 23 ft |
| Installation | Hardwired or NEMA 14-50 |
| Certification | UL listed, Energy Star |
| Warranty | 3 years |
Skip this if: Skip it if your circuit is already fixed and you just want the cheapest safe 40 A unit. You are paying for flexibility you will not use.
Specifications above are the manufacturer’s published figures. Source: ChargePoint, ChargePoint. We have not tested this unit — see how we pick.
2. Harsh weather and no app
Grizzl-E Classic
United Chargers · J1772 · 40 A / 9.6 kW · 24 ft cable
A cast-aluminum box with no app, no account and no firmware to update. If you want a charger that behaves like an appliance, this is the one.
What is good
- Cast aluminum NEMA 4 / IP67 enclosure, built for outdoor mounting
- No app, no account, no network dependency
- Amperage is set with physical switches, not software
- Protections for over-current, over-voltage, ground fault and over-temperature
What is not
- 40 A ceiling, slower than the 48 A units if your panel can take more
- No scheduling, so off-peak charging has to be set in the car
- The cold-flexible 24 ft cable is only on the Extreme Edition
| Maximum output | 40 A / 9.6 kW at 240 V |
|---|---|
| Adjustable | 16, 24, 32 or 40 A |
| Connector | SAE J1772 |
| Cable | 24 ft on the Extreme Edition |
| Enclosure | Cast aluminum, NEMA 4 / IP67 |
| Certification | UL certified |
| Warranty | 3 years |
Skip this if: Skip it if you want scheduled charging or energy tracking in an app. The Classic deliberately has neither.
Specifications above are the manufacturer’s published figures. Source: United Chargers, InsideEVs. We have not tested this unit — see how we pick.
3. The best portable overall
J+ Booster 2
J+ Americas · J1772 · 40 A / 9.6 kW · 25 ft cable
A 40 A portable in a military-grade aluminum body, ETL certified to UL standards and IP67 rated, weighing 2.2 lb without cables. The portable that behaves like a wall unit.
What is good
- 40 A, matching many wall-mounted units
- Eight amperage settings from 6 A to 40 A, so it fits almost any outlet
- Adapters for a wide range of outlets, including NEMA TT-30 for campgrounds
- IP67 and drive-over resistant, which portables usually are not
- 2.2 lb without cables, so it genuinely travels
What is not
- Costs more than most portables, and more than some wall units
- Every extra outlet adapter is a separate purchase
- Still a portable, so it is not rated for permanent outdoor mounting
| Maximum output | 40 A / 9.6 kW at 240 V |
|---|---|
| Adjustable | 6, 8, 12, 16, 20, 24, 32 or 40 A |
| Power range | 1.4 kW to 9.6 kW |
| Connector | SAE J1772 |
| Cable | 21 ft or 25 ft, depending on version |
| Adapters included | NEMA 14-50 and 5-15 |
| Further adapters available | 5-20, 6-15, 6-20, 6-50, TT-30 |
| Weight | 2.2 lb without cables; 7 lb with cables and adapters |
| Body | Military-grade aluminum, drive-over resistant to 6,600 lb wheel loads |
| Rating | IP67 waterproof and dustproof |
| Certification | ETL certified to UL standards |
Skip this if: Skip it if you only ever charge in one place. A hardwired wall unit is cheaper for a fixed installation.
Specifications above are the manufacturer’s published figures. Source: J+ Americas. We have not tested this unit — see how we pick.
FAQ
Questions people actually ask
Can I use a 40 amp breaker for an EV charger?
What EV charger should I use on a 40 amp circuit?
Can I put a NEMA 14-50 on a 40 amp breaker?
Sources
Where these numbers come from
- ChargePoint Home Flex specifications and ordering information — ChargePoint
- Grizzl-E Classic — United Chargers
- J+ Booster 2 Level 2 portable EV charger — J+ Booster
- NEC Article 625: EV charging equipment — WireRefContinuous-load rule behind every circuit figure on this page.
- Article 210: branch circuit requirements — WireRefLists a 40 A circuit for a 32 A Level 2 charger. Fetched 2026-09-10.
- NEC Table 210.21(B)(3) -- receptacle ratings for various size circuits (discussion) — Mike Holt's ForumA 40 A circuit may carry a 40 or 50 A receptacle. Fetched 2026-09-10.
Read next
Related reading
- The best EV chargers for a 30-amp circuitWhat a 30-amp circuit gives you, and two adjustable chargers that can be set to 24 A.
- How many amps do you actually need?Three checks that determine your charger amperage, and why the smallest one wins.
- The best 40-amp EV chargersWhy 40 A is the sweet spot for most homes, and the units that do it well.
- 32 A vs 40 A vs 48 A: how many amps do you actually need?What each amperage tier delivers in miles per hour, and the circuit each one requires.