According to The Healthcare Facilities Code (NFPA 99), circuits in “Wet Procedure Locations” shall be supplied by either an Isolated Power Systems (IPS) or a Grounded Power system with Class-A GFCIs. This states operating rooms are considered to be a wet procedure location unless a risk assessment conducted by the health care governing body determines otherwise. This means that unless a risk assessment is conducted, then operating rooms are considered to be wet procedure locations by default. In Operating Rooms (ORs) and other critical care spaces, Isolated power is typically chosen over GFCIs as the IPS allows for a continuity of power during an initial ground-fault. When designing such spaces, it is important not to overlook power requirements for specialty medical equipment (most commonly surgical lasers) operating at voltages other than 120V.
The National Electric Code (NEC) only permits an Isolated power system to supply circuits in multiple ORs if 1) the secondary voltage is 150V or greater and 2) the receptacle mating plugs are not interchangeable with the other local Isolated Power System (typically 120V system). This article will discuss the most typical arrangements for Isolated Power Systems for such specialty equipment needs.