Martindale pd430 440v universal 2 range proving device martindale marpd430 p the martindale pd430 is a 440v ac proving unit designed to enable voltage indicators to be fully checked in compliance with health amp safety recommendations using a voltage indicator without first proving it is working correctly could be fatal p p the pd430 features a low 50v check as well as a high 440v check and is compatible with the martindale vi13700g and the new martindale vi13700 2 this model is