The extra 8 A is real in exactly one place: on a 50 A circuit. Everywhere else it disappears — on a 40 A circuit, the EV-ACS4005T has to be set to 32 A, which is the EV-ACS3210T‘s maximum, and both chargers deliver the same 7.7 kW or so. So the “32a vs 40a charger” question is decided by your breaker first, your car second, and your sessions third.
Key Takeaways
- On 20, 30 and 40 A circuits, both chargers run at identical settings — the extra 8 A exists only on a 50 A circuit.
- The car must also accept more than about 7.7 kW of AC power, or the gap never appears.
- Where the gap exists, it buys time on large top-ups, not on nightly ones.
- The EV-ACS3210T’s six steps from 10 A are its own advantage: fit for smaller circuits.
Gate One: The Circuit You Actually Have
A charger’s setting must follow the circuit, under the NEC continuous-load rule: the breaker is sized at 125% of the charging current. Read both chargers against the circuit classes a home actually has:
| Breaker behind the outlet | EV-ACS3210T highest setting | EV-ACS4005T highest setting | Any difference? |
|---|---|---|---|
| 20 A | 16 A (about 3.8 kW) | 16 A (about 3.8 kW) | None |
| 30 A | 24 A (about 5.8 kW) | 24 A (about 5.8 kW) | None |
| 40 A | 32 A (about 7.7 kW) | 32 A (about 7.7 kW) | None |
| 50 A | 32 A (about 7.7 kW) | 40 A (9.6 kW) | The 8 A exists — here only |
The 40 A row is the one that matters most, because a 40 A circuit is the natural home for a 32 A portable charger — and it is precisely where the bigger unit gives its advantage back. Our guide to what size breaker an EV charger needs works through the pairings in full. If your outlet sits on anything below a 50 A breaker, the two chargers are the same charger, at the same speed, tonight.
Gate Two: The Car Has to Accept the Power
Suppose the circuit is a full 50 A. The extra 8 A still only flows if the car’s onboard charger accepts more than about 7.7 kW of AC power. The car sets the real rate: a car whose AC limit is at or below 7.7 kW charges identically on both units, on any circuit. Cars differ widely here, so check your own car’s AC charging figure — in its specifications or manual — before the chargers’ nameplates mean anything. Our explainer on how many amps an EV charger needs covers how the car’s limit and the charger’s setting interact.
Gate Three: The Session Has to Be Big Enough
With both gates open, what the 8 A buys is time on large top-ups, and only there. As labelled arithmetic at full rate, before losses and the car’s taper: adding 30 kWh takes about 3.9 hours at 7.7 kW and about 3.1 hours at 9.6 kW. That gap is worth having on a big battery that comes home low. On a typical evening top-up of a few kWh, the same gap shrinks to minutes neither driver will notice.
The Two Chargers, Read Through the Gates
The EV-ACS3210T tops out at 32 A (about 7.7 kW), adjusts in six steps from 10 A, and carries a NACS connector on a NEMA 14-50P plug, IP66-sealed. Its counter-argument to the bigger unit is the ladder itself: the low, fine steps fit smaller circuits and borrowed outlets that a 40 A unit must also turn down for. The EV-ACS4005T raises the ceiling to 40 A and 9.6 kW, with four settings and a choice of 25 ft or 28 ft cable — a real asset, but one that only unlocks behind a 50 A circuit and an accepting car.
Frequently Asked Questions
My outlet is on a 40 A circuit. Is the EV-ACS4005T pointless?
Not pointless, but on that circuit it runs at its 32 A setting and charges exactly like the 32 A unit. Its extra becomes real only if the circuit is upgraded to 50 A — an electrician’s job — and your car can accept the higher rate.
My car accepts 11 kW on AC. Should I buy the 40 A charger?
Only if the circuit is 50 A as well. Both gates have to open: an accepting car on a 40 A circuit still charges at 32 A, because the setting follows the breaker.
What does the 32 A unit do better, then?
Fit. Six settings from 10 A let it match smaller and shared circuits more precisely, which is the same reason portable chargers work across so many outlets. The 40 A unit’s advantage is a ceiling; the 32 A unit’s is range at the bottom.
Related Reading
- What Size Breaker Do I Need for an EV Charger?
- How Many Amps Does an EV Charger Need?
- Do Portable EV Chargers Work? How Speed Depends on the Outlet
- What Is a NEMA 14-50 Outlet? A Guide for EV Owners
