Only Deandra Dottin, who made a hundred off 38 balls in the 2010 T20 World Cup, has made a faster century.
Her knock included 13 fours and the half-century came off 23 balls, meaning she needed just 19 more for the second 50.
Dropped on 92, she made the most of it to bring up her second century in the tournament.
‘I’ve been working on a back-of-the-length baseball type slog, and so when it sits up and comes into my hip, I can just have a swing and clear the fence, because I’m strong enough,’ said Harris after her innings.
The previous record for a WBBL ton was Ash Gardner’s 47-ball effort in the last edition.