Question. At my in laws they have a 3 prong 240vac, 50 amp rated outlet. It has L1, L2 and ground but no neutral. Rather than adding a new plug I was thinking of making a pig tail adapter to convert the 3 prong plug to the modern 4 prong, that includes the neutral. if I do that, of course the neutral would be unconnected. This is fine for some equipment. Is it okay for the Tesla mobile charger? Has anybody tried this? It makes sense to me that the neutral would be unused.