EV Charger Installation Calculator

This changes the charge speed, the hours to full and the battery capacity used. Wire, breaker, ground and panel capacity are sized from the charger, never from the car (NEC 625.41, 625.42).

NEC 625.41, 625.42

The one route the NEC gives for a smaller branch is the EVSE's own restricted-access adjusted setting under NEC 625.42(B), and it is a route a calculator cannot take for you: the conditions it attaches, under 750.30(C) and the manufacturer's instructions, are facts about installed equipment. The 4 this tool can name are not a full compliance checklist. Size from the full rating unless a qualified person has verified them, and 625.42(B) itself, on site.

NEC 625.42(B), 750.30(C), 110.3(B)

NEC 625.42(A) reaches the service and feeder load calculation; only (B) changes the EVSE's own ampere rating, which is what 625.41 sizes the branch from. The conductor, breaker and ground above stay sized to 125% of the charger's full output.

NEC 625.41, 625.42(A)

Your answer above used the 30-day recorded peak, which is NEC 220.87's exception rather than its main rule. That exception is not permitted where the service has a renewable energy system (solar PV, wind) or any form of peak load shaving. If you install load management here, a later 220.87 check on this service cannot rest on a new 30-day recording; it needs 12 months of utility demand data.

The NEC does not define peak load shaving, and where it does use the term, at 700.4(C)(1), it is describing a source running in parallel rather than a device that limits load. Reading an EV energy management system as a form of peak load shaving is our interpretation, and it is the conservative one: check it with the AHJ before relying on a 30-day recorded basis on a service that has one.

NEC 220.87

These sizes are at 86 F ambient with 1-3 current-carrying conductors, which is the basis the ampacity tables are printed at. A hotter run, or more current-carrying conductors sharing the raceway, derates the conductor under NEC 310.15(B)(1) and NEC Table 310.15(C)(1) and can call for a larger one. The Intry EV charger calculator sizes for the conditions you enter.

NEC 310.15(B)(1), Table 310.15(C)(1), Table 310.16

You named this vehicle; Intry has not seen the car and has not verified its configuration. Onboard ratings can differ by trim and model year.

These are the vehicles Intry holds a manufacturer specification document for, keyed to a model year, and the list grows as each new document is sourced. GM (Silverado EV, Blazer EV, Equinox EV): Intry holds no manufacturer specification document giving an onboard charger rating for them, which is a statement about those documents and NOT a statement that those cars cannot be charged. Those vehicles can still be chosen in the vehicle picker, where the figures EPA itself publishes are shown and no rating is taken from the car. Intry also holds published figures for Tesla and Rivian that no roster record can use; the vehicle page shows each document and what it states. For any other vehicle the charge speed uses a site-wide average with no manufacturer figure behind it, and the answer says so where it does.

Every figure an Intry calculator computes comes from a locked source module, not hand-typed. 28790 automated checks re-derive and source-check the numbers against the cited NEC section before each deploy. This is our own deterministic gate, not a third-party audit. The per-tool receipt is public at https://www.intrysys.com/verified.

Yes. A hardwired Level 2 EV charger must be on a dedicated branch circuit that serves no other loads (NEC 625.40), with conductors and overcurrent protection sized at 125 percent of the charger's continuous output because EVSE is a continuous load (NEC 210.20(A), 625.42). NEC 625.40's own Exception permits one branch circuit to feed multiple EVSEs where 625.42(A) or (B) allows it; it does not permit an EVSE to share a circuit with an ordinary appliance. That means a 48A charger needs a 60A circuit and a 40A charger needs a 50A circuit, both standard breaker sizes. A plug-in Level 2 unit is no exception: its receptacle, typically a NEMA 14-50, must sit on its own individual branch circuit too, so every Level 2 install gets a dedicated circuit.

A 48A EV charger requires a 60A breaker. EV charging is classified as a continuous load per NEC 625.42, so conductors and overcurrent protection must be rated at 125% of the load: 48A × 1.25 = 60A. This is enforced by NEC 210.20(A).

A 48A EV charger needs #6 AWG copper wire on a 60A breaker, and a 40A charger needs #8 AWG copper on a 50A breaker. EV charging is a continuous load, so the wire is sized at 125% of the charger's rating (NEC 625.42): 48A × 1.25 = 60A, which #6 copper carries per NEC Table 310.16. Aluminum goes one size larger (#4 AWG aluminum for a 48A charger). On runs longer than about 50 feet, check voltage drop and upsize if needed.

A Tesla Wall Connector (48A, 240V) needs #6 AWG copper conductors with a 60A breaker. For runs over 50 feet, check voltage drop. You may need to upsize to #4 AWG to stay within the recommended 3% drop. Aluminum wire requires one size larger (#4 AWG for standard runs).

NEC 625.54 requires GFCI protection for cord-and-plug connected EVSE, meaning any charger plugged into a NEMA 14-50 or similar outlet needs a GFCI breaker at the panel. Hardwired chargers like the Tesla Wall Connector Gen 3 have built-in GFCI/CCID protection that satisfies the code requirement. Always check the manufacturer's installation instructions.

Under NEC 220.87 a 200A service fits a 48A charger (a 60A breaker) as long as your 12-month metered peak demand is at or under 121.6A. Enter your metered peak on this page and the calculator runs that 220.87 check; with no reading it falls back to a labelled breaker-percentage estimate, which is not an NEC method. If the metered peak runs higher, add a listed NEC 625.42(A) load management device, in accordance with NEC 750.30, or plan a panel upgrade.

Level 1 uses a standard 120V outlet and adds only a few miles of range per hour, which is too slow for most daily drivers. Level 2 uses 240V and is what this calculator sizes. How many miles per hour a Level 2 circuit adds depends on the car as much as on the amperage: across the vehicles Intry holds a fetched EPA consumption record for, a 32A charger adds 15.6 to 26.3 mi/hr and a 48A charger adds 21.4 to 37.3 mi/hr, and no vehicle in Intry's sourced roster accepts more than 48A. Choose one of the vehicles named under the picker, which are the ones Intry holds a manufacturer specification document for, and the charge-rate ceiling is read from that document. For any other vehicle the picker shows what EPA publishes for it and the charge speed uses the site-wide average, and the answer says which it used. Level 3 (DC fast charging) is commercial only and requires 480V three-phase.

Installed cost depends on panel proximity, wire run length, whether the existing service has capacity or needs an upgrade, conduit requirements, and local labor rates, so it varies widely by region and by job. We do not publish a price range, because a figure that is right in one market and one month is wrong in another. What this calculator gives you is the code-required sizing for your circuit (conductor size and material, breaker, equipment grounding conductor, and, where the install calls for one, the receptacle or the disconnect), which you can price at your own supplier. It sizes the circuit; it is not a full bill of materials, so it will not account for a quote's raceway, boxes, fittings, terminations or labour.

EV charging has approximately 15% energy loss from heat generation and AC-to-DC conversion. A 48A/240V circuit delivers 11.5 kW, but only about 9.8 kW reaches the battery. The calculator applies that loss to the charging rate and to the hours-to-full figure. It does not apply it to miles of range per hour: that figure divides wall-side energy by a wall-side consumption rating which already includes charging losses, so applying the loss again would count it twice.