Wiring:The iWave-R incorporates a patented universal voltage 24VAC to 240VAC enter ability. The black wire (marked ‘AC’ on label) is for 24VAC to 240VAC voltage input. The white wire (marked ‘N’ about the label) would be the neutral leg for 24VAC or 120VAC; or the opposite very hot leg https://npo-authority03578.blogoscience.com/34664354/the-definitive-guide-to-npo-authority