A while back I posted on the 4 to 5 pin three phase converters I did, here. Today I’m publishing some helping details.
1. Wire diagram / schematics. All connections are direct; 4 pin plug to 5 pin plug: L1 to L1, L2 to L2, L3 to L3, Ground G to Ground G; the Neutral N has to be fetched from the Schuko; Schuko to neon (lamp): L to lamp, G to lamp; Schuko to 5 pin plug: N on the Schuko to N on the 5 pin plug – this only happens when the lamp is ON, see bullet 4.
2. Does this adaptor work always? It has worked OK, but ultimately it will depend a lot more on the original electrical installation, if it has good Ground connection, if the wires are the correct square section, more on this in the end.
3. What’s the charge speed? It all depends on the installation, really; I did an adaptor for 16 A three phase 11 kW (up to 55 km/h) and another one for 32 A three phase 22 kW (up to 110 km/h if the car has the dual charger option; newer cars can only go up to 16.5 kW with the upgraded charger, up to more or less 82 km/h).
4. What’s the Schuko for? The 4 pin plug only has the three phases (L1, L2, L3) and Ground; the Tesla UMC and other EV chargers also need the Neutral, and that’s the Neutral that we get from the Schuko plug; for this we need to be sure the Schuko is plugged in the correct sense – in some countries (Belgium) this is imposed by an extra large pin in the Schuko, but in other countries (Portugal included) that pin is not present; the “lamp” (a neon) is used to determine if the Schuko is in the good position; if it lights it’s OK, the L is in the L pin (not used, just for the “lamp”) and Neutral is used for the 5 pin plug; if the lamp does not light up the Schuko has to be “reversed”: unplug it and plug it again but twisting it 180° for the lamp to be connected to L.
On charging: if the Ground is considered not good enough, or there’s some minor problem in one phase or the Neutral, the Tesla UMC refuses to charge. In Spain, Tordesillas, a friend got stuck at the Parador while having access to a 5 pin red plug 22 kW standard installation, because the UMC refused to charge, it’s really very sensitive. That’s why I always use a backup charger, a 22 kW wallbox-ok efimarket charger: not only can I charge double the speed of the UMC (limited to 11 kW) but it enables charging also in places where the UMC suffers from being too sensitive.
On security issues: the car detects any issue. The wallbox-ok charger complies with every possible standard and it’s reliable and secure. There’s too much sensitivity in the Tesla UMC that, in some cases, not even Tesla themselves can understand or help you on the hotline help for electrical installations that obey to the standards, that have passed conformity evaluations and yet aren’t or seem not to be good enough for the UMC. But hey, in the end, it’s up to you, the owner, the user, to decide what to do and/or use: your milage may vary.