Medical Isolated Power System Design and Installation Instruction

Isolated Power System is ungrounded power source (IT), use medical grade low leakage isolation transformer to isolate the Neutral from the Earth, but due to the leakage current produced by the insulation of the wires and the loads so we need to minimize this hazard current under the specified limit to avoid any leakage current to pass through the patent when the used medical equipment got failure. The following instructions should be followed to achieve maximum isolation in the isolated power system:

 

1.      Recommended to use maximum 10 KVA isolation transformer per panel to minimize the leakage/hazard current produce by the medical Load.

2.      For special high-power loads like X-ray & Laser, should not be supplied with the same IPP for medical loads, a dedicated IPP for this load should be used with higher KVA rating if required.

3.      16 Circuits maximum can be used for each isolation transformer.

4.       Due to the transformer initial current which may exceed 8 x transformer nominal current, it is recommended to use upstream protection with adjustable trip delay time, or size the protection 10-20 Amper higher than the one used in the isolation panel.

5.      To minimize the leakage current produced by Isolated Power Panel (IPP) outgoing wiring the panel should installed as close as possible to the load, so better to installed inside the room (OR, ICU, …).

6.      Remote indicator is required to duplicate the alarm of the Line Isolation Monitor (LIM) to the medical staff inside the room that incase of the panel installed outside the room.

7.      The medical equipment only (which will serve the patent) should be supplied from the Isolated Power Panel (IPP), like pendant sockets dedicated for medical equipment, surgical light. Other loads will not contact with the patent like lighting, wall monitors, wall panels, etc. Must Not supplied from IPP, this type of load will increase the leakage/hazard current of the isolated system.

8.      The outgoing wiring of the IPP should be low leakage type like XHHW for both power conductors, for grounding conductor normal cable can be used.

9.      The total length of the IPP’s out going circuits (sum of length of all circuits) should not exceed 150 meters to minimize the leakage/hazard current produce by the wire.

10.   Do not use pulling compounds to lubricate inside of conduit.

11.   Use conduit with larger diameter to avoid damage to wire insulation during pulling the wire.

12.   The outgoing wiring of the IPP must not be pulled in the same cable try or conduit of non-isolated wiring (like incoming cable) or isolated wiring of another IPP.

13.   The growing terminal of all loads supplied by the IPP (including the grounding of the floor) must be connected the ground bar inside the IPP.

14.   If there is more than one IPP used inside the same room, the grounding bars of all of them must be bonded together