NEC Article 625 EV Charging
ChargePoint Home Flex Wire Size
The Home Flex is adjustable from 16 to 50 amps, so the wire follows the amperage you set. Here is the common 48A spec, the full dial-down table, and the plug-in versus hardwired difference.
Wire and Breaker by Amperage Setting
| Setting | Power (240V) | Breaker | Copper Wire (75°C) | Ground |
|---|---|---|---|---|
| 16A | 3.8 kW | 20A | #12 | #12 |
| 24A | 5.8 kW | 30A | #10 | #10 |
| 32A | 7.7 kW | 40A | #8 | #10 |
| 40A | 9.6 kW | 50A | #8 | #10 |
| 48A | 11.5 kW | 60A | #6 | #10 |
| 50A (max) | 12.0 kW | 70A | #6 | #8 |
Sizing a circuit from a dialled-down setting rather than from the unit's 50 A rating is NEC 625.42(B), and 625.42(B) attaches conditions. They are facts about the installed equipment, so no calculator can check them and this page does not claim they hold on your job. A qualified person verifies them on site, or the circuit is sized from the full rating:
- Where the adjusting means is part of an energy management system, that system uses monitoring and controls to automatically cease current flow if it malfunctions. 750.30(C) applies its subdivisions where an EMS is used to limit the current on a conductor. (NEC 750.30(C)(2))
- Access to the ampere adjusting means is restricted by at least one of the five means 750.30(C)(3) names: behind a removable and sealable cover over the adjustment, behind a cover or door that needs a tool to open, behind a locked door accessible only to qualified personnel, password protected with the password held by qualified personnel only, or software whose access to the adjusting means is password protected for qualified personnel only. (NEC 750.30(C)(3))
- The equipment supplying the branch circuit is field marked with the maximum current setting, the date of the calculation and setting, identification of the loads and sources associated with the current limiting feature, and the words "The setting for the EMS current limiting feature shall not be bypassed". Those markings meet the requirements in 110.21(B) and are located so they are clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment. (NEC 750.30(C)(4))
- The adjustment was made in accordance with the manufacturer's instructions, and the adjusted rating appears on the rating label with enough durability to withstand the environment involved. (NEC 625.42(B) / 110.3(B))
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.
Wire at the 75°C column (EV equipment is 75°C-rated); on NM-B cable at 60°C the 48A setting needs #4 copper instead of #6. The 50A row uses #6 on a 70A breaker via the NEC 240.4(B) next-standard-size allowance, because the Home Flex terminals accept up to #6 AWG. Built-in GFCI, so a hardwired install uses a standard breaker, not a GFCI breaker.
Hardwired for 48A, or Plug-In for 40A
The Home Flex comes in two forms. The hardwired version reaches the full 48A (or 50A) and, because it has built-in CCID ground-fault protection, connects to a standard 60A breaker with no GFCI breaker required. The plug-in version, with a NEMA 14-50 or 6-50 plug, is capped at 40A continuous on a 50A receptacle (the 80% rule), and being cord-and-plug it needs a GFCI breaker per NEC 625.54. So for the fastest charging, hardwire it; for portability or an existing 14-50 outlet, plug it in and accept the 40A cap.
Size Your Home Flex Install
Set the charger amperage you plan to use and enter your run and panel to get the exact wire, voltage drop, panel-capacity check, and a parts list.
Frequently Asked Questions
What size wire does a ChargePoint Home Flex need?
It depends on the amperage you set it to, because the Home Flex is adjustable from 16A up to 50A. At 48A hardwired it needs #6 copper on a 60A breaker with a #10 ground, the same as a Tesla Wall Connector. A lower setting goes with a smaller circuit: 40A needs #8 copper on a 50A breaker, 32A needs #8 on a 40A breaker. A setting sizes the circuit only where NEC 625.42(B) and NEC 750.30(C) are satisfied on the installed unit. Set the amperage in the app to match the breaker and wire you install, at 80% of the breaker for this continuous load.
What breaker does a ChargePoint Home Flex use?
At the 48A setting, a 60A double-pole breaker (48A x 1.25 = 60A). The Home Flex is a hardwired charger with built-in ground-fault protection (CCID), so it does not need a GFCI breaker, just a standard 60A two-pole breaker. Set to 40A it uses a 50A breaker, and at its 50A maximum it needs a 70A breaker. Whatever you choose, the charger's app setting must be at or below 80% of the breaker.
Can the ChargePoint Home Flex charge at 50 amps?
Yes, that is its maximum, but it takes more than a 60A circuit. A 50A continuous load needs a 70A breaker (50 x 1.25 = 62.5A, rounded up), and because the Home Flex terminals accept up to #6 AWG, a 50A hardwired install uses #6 copper on that 70A breaker under the NEC 240.4(B) next-standard-size rule. Setting it to 48A on a 60A circuit is the cheaper install, at 11.5 kW against 12 kW.
Can I plug in a ChargePoint Home Flex instead of hardwiring?
Yes. The Home Flex comes in a plug-in version with a NEMA 14-50 (or 6-50) plug, which limits it to 40A continuous on a 50A receptacle, because a plug-in charger is capped at 80% of the circuit (NEC 210.20(A), 625.42). A plug-in install on a 14-50 or 6-50 needs a GFCI breaker (NEC 625.54). To get the full 48A or 50A you must hardwire it, which is why the hardwired version is the choice for fastest charging.
Is the ChargePoint Home Flex wire size the same as a Tesla Wall Connector?
At 48A, yes: both use #6 copper on a 60A breaker with a #10 ground, and both are hardwired with built-in GFCI so neither needs a GFCI breaker. The difference is the top end: the Tesla Wall Connector tops out at 48A, while the Home Flex can be pushed to 50A on a 70A circuit. Below 50A the two are wired identically.
Related EV References
Tesla Wall Connector Wire Size
The other adjustable hardwired charger: 48A on a 60A circuit, with its dial-down table.
48 Amp EV Charger Wire Size
The full spec for the 48A setting: #6 copper, 60A breaker, ground.
Will My Panel Handle It?
Check whether your panel has room for a 60A charger circuit.
EV Charger Calculator
Wire, breaker, panel, and GFCI for any EV charger install per NEC 625.