Wiring:The iWave-R provides 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’ on the label) is the neutral leg for 24VAC or 120VAC; or the other very hot leg for 208/240VAC.This offers An additional layer of transparency and prot