The sides went level at half-time at 0-7 apiece, but both were unlucky not to find the net during the opening period.
Wexford’s Adrian Flynn forced a fine save from Donal O’Sullivan from close range near the end of the half and had to settle for a point.
Moments later Darragh Tracey won a penalty for Limerick at the far end, but Iain Corbett’s spot-kick flew over the crossbar.
In a cagey second-half, there was little to separate the teams. A brace of scores from Banville and one from John Tubritt edged Wexford into the lead, but Danny Neville, Jamie Lee (free) and Sean O’Dea hit points to leave the game poised at 0-10 each after 60 minutes.
Ciaran Lyng and Darragh Treacy traded scores down the stretch, before Banville hit what turned out to be the winner with 90 seconds left.
Wexford – S Roche; M Furlong (0-2), B Malone, J Rossiter; E Nolan, J Wadding, T Rossiter; D Waters, N Rossiter; B Brosnan, K O’Grady, A Flynn (0-1); C Carty, C Lyng (0-4, 2f), PJ Banville (0-4, 1f). Subs: J Tubritt (0-1) for K O’Grady, P Curtis for B Brosnan, J Firman for A Flynn.