text: Both sides remain in qualifying places with Essex top on run-rate and Glamorgan in third.
  Essex make one change with Jamie Porter replacing Matt Quinn in their seam attack., while Glamorgan are unchanged.
  Glamorgan won the toss and captain Jacques Rudolph chose to bat first on a cloudy afternoon.
  Both teams face a hectic schedule of five limited-overs games in a week, as the One-Day Cup and T20 Blast groups both reach their climax.
  Essex lost to Surrey by 66 runs despite 131 from Jesse Ryder, while Glamorgan went down by 33 runs away to Somerset,  in their previous matches.
  "Though we're still in the top four, a win (over Somerset) would have set us on the way to a quarter-final- we want to win every game" Glamorgan fast bowler Michael Hogan told BBC Wales.
  Essex coach Chris Silverwood told the club's website "The players know they have to bring consistency to their game,  if we are to ensure Essex are in the quarter-finals of both white-ball competitions, and we need to start with a win against Glamorgan."
  Glamorgan won the 2015 match in Cardiff by 146 runs, with Colin Ingram hitting 130.
  Essex : Browne, Westley, Ryder, Bopara (c), Lawrence, ten Doeschate, Foster, Zaidi, Napier, Masters, Porter.
  Glamorgan: Lloyd, Rudolph (c), Bragg, Ingram, Donald, Wallace, Wagg, Meschede, Salter, van der Gugten, Hogan.
target: Essex and Glamorgan will be looking to recover from defeats as they meet at Chelmsford in the One-Day Cup.