[ethbr0]

I am not an electrician, but wouldn't all US wiring already be 240v-compatible (at currently rated amperages) if the connectors were upgraded?

US residential has 240v at the home fuse box from the upstream 3-phase.

But I imagine it'd require a big adjustment at the utility level if everyone started drawing from +120v & -120v, instead of the current balance around the neutral.

[quickthrowman]

The vast majority of US homes use NM cable (romex) which is rated for 600v.

NEC 2020 edition, Article 334 Non-Metallic Sheathed Cable

334.104 Conductors.

The 600-volt insulated power conductors shall be sizes 14 AWG through 2 AWG copper conductors or sizes 12 AWG through 2 AWG aluminum or copper-clad aluminum conductors.

[ethbr0]

So the in-wall would be good, but the standard socket (NEMA 5-15) definitely isn't rated for 240v and would need upgrading.

[quickthrowman]

Correct, a residential NEMA 5-15 receptacle is only rated for 125v. There are some dual amp/dual voltage (15a/20a, 125v/250v) receptacles out there, but you almost certainly won’t see them in a house. NEMA 6-20 is rated for 20a at 250v.

More dual amp/dual volt wiring devices: https://www.plugsocketmuseum.nl/NorthAm1combi.html

[briHass]

Yes, it's the amps that matter for wire gauge (at typical voltages). Regular 12/2 or 14/2 NM cable (Romex) is used for US 240v circuits all the time. The only requirement is to color the white wire at the ends black or red to signify that it is a hot conductor with reference to ground.

[organsnyder]

I would think so, but I am also not an electrician. I'm guessing the biggest issues would be the chicken-and-egg problem of upgrading receptacles and devices, as well as the question of whether 240v is actually a prudent choice to begin with.