following his resignation from tauranga borough council lloyd mandeno took up a position as general manager of the tauranga electric power board in january 1926. he was only in the position until he resigned on 25 may of that year, leaving the position in august, to go into private practice in auckland. however the board retained him as their consulting engineer on an annual retaining fee of £250 plus travelling expenses, a position he retained until 1929. during his period of evolvement with the power board he invented, developed and introduced into service the single wire earth return reticulation system. this allowed the board to reduce the cost of distributing electricity across its predominately rural customer base.