Appellants, plaintiffs below, appeal from a directed verdict granted against them in this negligence action. We reverse the directed verdict and remand for a new trial.

Directed verdicts in negligence cases must be granted in an especially cautious manner. Collins v. School Board of Broward County, 471 So.2d 560, 563 (Fla. 4th DCA 1985), review dismissed, 491 So.2d 280 (Fla. 1986). A judge is prohibited from acting as a substitute fact-finder on the weight of the evidence presented at trial by granting a directed verdict. St. Lucie County v. Federal Constr. Co., 584 So.2d 122, 123 (Fla. 4th DCA 1991). On this record, we find that there was sufficient evidence of appellee’s negligence to send the case to the jury. In particular, the very morning of the incident the appel-lee had attempted to repair the unit from which later appellant received a serious electrical shock. There was evidence that appellee told appellant’s supervisor that it was okay to use the unit. It was for the jury to decide the issues of negligence on the evidence presented. Therefore, it was error to grant appellee’s motion for directed verdict.

Reversed.