I see construction electrical spider boxes with single phase 125-250VAC split three wire + ground systems, and they are connected with 50AMP cables and sockets. Here are some web pages showing the connectors: CS6364N - Marinco - Actuant Electrical - Twist Lock Plugs | Galco Industrial Electronics Excerpt: "Connector, 50A, 125/250V, 3-Pole, 4-Wire, California Standard" California Standard Pro-Grip Plug & Connector 50A, 125/250V/AC Non-NEMA 3-Pole/4-Wire - CS6365EX, CS6364EX Excerpt: "California Standard Pro-Grip Plug & Connector 50A, 125/250V/AC Non-NEMA 3-Pole/4-Wire" Hubbell 50A Twist-Lock Receptacles (California Standard) Excerpt: "Hubbell 50A Twist-Lock® Receptacles (CA Style)" Hubbell 50A Twist-Lock Plugs and Connectors | California Style, CA Standard 50 Amp Locking Plug Excerpt: "California 50A Twist-Lock® Plugs and Connectors" They make Y's, spider boxes, and cords. Here's a cord: Milspec Industries, Inc. - 6/3-8/1 STW (600V) Temporary Power Extension Cords with CGMâ„¢ and a spider box: Spider Box - Temporary Power Box Typically, I see more standardized boxes that aren't frankenstein types like the above, but these give you an idea. Hubbel is a more standard supplier, I think, but I haven't thoroughly investigated. I'm wondering: can a Tesla cord be made to plug into the output side of one of those spider boxes and then into the Tesla? I'm thinking of building a box that has a receptacle for a standard 50Amp California Standard temporary cord, a meter to measure how much energy is taken, and a HPWC, with rubber on the outside, all to fit in the trunk or frunk, and then destination charge whenever I'm near one of those connectors. I could use the meter measurement to reimburse the people I get power from. I would negotiate every time I get near one of those boxes with the owners of that electricity before plugging in and follow the agreed upon terms. I could set usage parameters inside the car in terms of max draw. I would be careful only to source power from grid-connected sources; many of those temporary power cords actually connect up to diesel gensets like MQ Power.