32 A charger, hardwired on a 40 A breaker: parts list
Short answer: A 32 A charger needs a 40 A two-pole breaker, because the breaker must be at least 125% of the charger's continuous rating. 8 AWG copper covers 40 A in both the 60°C and 75°C columns of Table 310.16.
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| Part | What to use |
|---|---|
| Circuit breaker | 40 A two-pole (32 A × 125% = 40 A) |
| Wire | 8 AWG copper THHN/THWN (50 A at 75°C) or 8 AWG NM-B cable (40 A at 60°C) |
| Conduit | ¾ in. is the Tesla Wall Connector's default entry; 1 in. is optional |
| Charger | Hardwired wall unit set to 32 A (Tesla Gen 3: 40 A breaker → 32 A output) |
| Protection | Tesla's Wall Connector has built-in ground-fault protection; its manual says not to add a GFCI breaker |
Power you get
| At 240 V | 7.6 kW |
|---|---|
| At 208 V | 6.7 kW |
| Added in 8 hours | 60.8 kWh |
Things to check
- Tesla lists a 40 A breaker as giving 32 A and 7.6 kW at 240 V.
- On 208 V apartment service the same 32 A works out to about 6.7 kW.
- 8 AWG is the smallest copper size here that NM-B cable allows at 40 A, because NM-B is limited to its 60°C rating (NEC 334.80).
Ground-wire size is not listed; your electrician sizes it under NEC Table 250.122. Have a licensed electrician do the work and pull the permit. All four setups.
Sources: Mike Holt – Article 625 Electric Vehicle Power Transfer System (PDF); NEC Table 310.16 ampacities (nectables.com restatement); Tesla – Gen 3 Wall Connector installation manual (PDF) (accessed 2026-10-25).