I do not know why a Wall Connector should cost any more to install than an 240 volt outlet. Assuming a 60 amp circuit, #6 THHN in conduit (or #6 MC cable) wire, no outlet, no outlet box, no GFCI breaker (just a regular $20 breaker). 50 amp outlet can use #8 THHN in conduit (or #8 MC cable)...