They struck twice inside three minutes, Richards plucking Thomas Leuluai's kick out of the air and grounding with ease before Hoffman dived over from three metres, after good work from Sam Tomkins.
Richards claimed the fourth try after pouncing on Thomas Leuluai's kick while Calderwood had the simple task of wrapping up the win with 10 minutes left on the clock.
Phelps finally made Wigan's early pressure pay when he got on the end of Sam Tomkins' kick-through, and only the faintest of finger-tip knock-ons by Richards prevented Amos Roberts adding to that score when he got on the end of Thomas Leuluai's high ball.