Electrical Distribution Controls: Medical Products & Isolation Panels Frequently Asked Questions

• Are there mandatory requirements in the law related to medical products?
• What is an Isolated Power System (IPS)?
• How can installing a Square D Isolated Power Panel help improve patient safety?
• What happens if a GFCI circuit should trip?
• What size panels do I need for the OR?
• Can Lasers, X-Rays and other pieces of medical equipment be used on Isolated Power Systems?
• In an Operating Room, does everything need to be on an Isolated Power System?
• Isolated Power Systems are too expensive.
• Are there specific requirements for installing an IPS?
• Are Isolated Power Systems required to be tested?
• Are there advantages to a Square D Isolated Power System?

NFPA 99 (2012) notes that hospital operating rooms are assumed to be wet procedure locations, unless a hospital determines them to be otherwise through a risk assessment.  Circuits protected Ground Fault Circuit Interruption (GFCI), or fed by an Isolated Power System (IPS) must be supplied used in wet procedure locations. Furthermore, if the location cannot tolerate an interruption of power (life support systems an example) then an Isolated Power System (IPS) must be used.

An IPS consists of an Isolated Power Panel (IPP) and circuits restricted to one room, typically. The panel has a transformer for isolating the power in the room, a Line Isolation Monitor (LIM), to monitor leakage current and up to 16 circuits. The isolation reduces shock and spark hazard, but must be monitored by the LIM. The Isolated Power Panels will go into an alarm state at 5 milliamps to indicate problem that would normally cause a GFI circuit to trip, but will continue to operate, even in a hazardous condition. Isolated Power Systems are required to be fed from a Critical Branch Circuit, which provides a non-interruptible power source. This, with the systems unique ability to operate under fault conditions, provides a power source that should be highly considered is areas that may present a hazard to both patient and personnel such as an Operating Room or Intensive Care Areas.

When someone is undergoing an invasive procedure, the patient is extremely susceptible to electric shock. In that state, <1 milliamp will kill a patient undergoing an invasive procedure. Most common ground fault protection is covered by GFCI, which will trip between 4 and 6 milliamps of leakage to ground, and could even pose a shock risk. An IPS will continue to operate safely under fault conditions while notifying the staff of a potential issue.

If a GFCI circuits trips with life-sustaining equipment, the equipment would be useless, especially if there were a problem with the equipment. First, it may not trip soon enough to protect a patient. (5 milliamps vs. <1). Secondly, when it trips, it interrupts the circuit, cutting off all power to the equipment. In the case of life-support or monitoring equipment, this unacceptable event can further endanger the patient.

Size is important in many things but in Isolated Power Systems, size is extremely critical. Isolated Power Systems are no designed to handle a large capacity load. The higher the loading of the panel, the higher the leakage will also be. It is recommended to design the panel to a minimum and not exceed 10 kVA. It is also recommended to keep the number of circuits at a minimum, 12 or less.

Medical Equipment requiring feeders greater the 120 volt can and should, and in many cases, be used on Isolated Power Systems. Many Lasers and X-Rays require 208 or 240 volt for operation. Due to the cost of this type of equipment, most healthcare facilities share the equipment. There are many options to operating these and other pieces of equipment.

In some areas, everything in the Operating Room is required to be on an Isolated Power System. Outside of these areas, the use of Grounded Power along with Isolated Power can be used. It is important to remember that in these areas the Grounded Power must be protected with GFCI

Isolated Power Systems do cost more both to install and maintain, but not to the degree, it has been reported. A properly installed IPS generally cost about 15 to 20% more then the conventional grounded power system. This is a small price for having the best power distribution available in a life safety situation.

The National Electric Code (517) has very specific requirements for the installation of IPS. Non-flexible metal conduit, specific wiring requirements, pulling compound, and even a recommendation of wire type lead to the successful installation of an Isolated Power System. Following the requirements and recommendations within the NEC, are only parts of the equation for a successful installation. Many other factors are not addressed in any code or written recommendation that can affect the installation. Each room can present their own issues and need to be dealt with accordingly.

NFPA-99 requires that IPS be to be tested after installation and prior to being placed into service. After that, the IPS, containing a self-testing, self-calibrating LIM, must be tested after and alterations or modifications have been done to the system. The IPS is also required to be tested not less then every 12 months with this type of LIM. If an older system is present and does not have a self-testing, self-calibrating LIM, this system must be tested and calibrated not less then every 6 months.

Square D has been at the forefront of Isolated Power Systems and Panels for many years. Starting in 1944 by introducing the Isolated Power Transformer to introducing the first true Line Isolation Monitor in the early 1970’s and the first Self-Testing, Self-Calibrating LIM in the early 1990’s, we have led the way in technology and design. With many different and unique offerings, Square D can design, modify, or upgrade almost any system today. Today’s products are sold globally and meet or exceed most local, state, and national code requirements.