This device belongs to the Vigilohm range designed to monitor ungrounded/IT electrical networks, in accordance to installation and products standards. PHT1000 is the Voltage Adaptor. It allows IM400, XM300 or XM200 monitor 1000VAC system if connected to a phase, 1700VAC if connected to the Neutral, or 1200VDC. It is to be installed between the Insulation Monitor and the electrical installtion to be monitored. PHT1000 allows the use of Insulation Fault location.