Operating Room Isolation Panel Problems

[ds124]

Hello to everyone. I am currently troubleshooting an operating room that keeps going into alarm on the (LIM) line isolation monitor.
This is a brand new room that was up and running for several weeks. Last week they had a bigger case than normal and brought in extra equipment. After the equipment was plugged in it went into alarm. The tech from the hospital went up and unplugged all unnecessary equipment. After that all the problems seemed to have started. The LIM would go from 2.7 milliamps down to .07. This continued throughout the surgery. I was called in to troubleshoot the problem. This is where I am at now with this room. If I plug in 3 particular pieces of equipment that is used daily in these rooms it will drive the LIM monitor into alarm as high as 7-8 milliamps then on its own fall back down to 2.4 milliamps or as low as .5 milliamps. Then on its own will drive right back up into alarm. This scenario will happen all day unless I unplug the equipment. All the equipment has been checked out and has been taken to other o.r. rooms with no problems. After checking all the wiring, plugs, connections ect. there are 3 things that have my attention and looking for some help on this.

1) I removed the ground bar from the isolation panel and had it floating with only the ground wires from the feed, the LIM and the transformer attached. With the bar floating it would go into alarm. If I removed just the ground wire coming from the feed the LIM would drop down to a normal reading and stay there. I put a megger on the feeder wires and all checked out. I even increased the ground wire size and temporary ran it to the ISO panel and still went into alarm.
2) I can only get the ISO panel LIM to fluctuate when I have these 3 pieces of equipment plugged in and turned on. I have tried the same type of equipment from other o.r. rooms and took this equipment to other rooms. The LIM still fluctuates.
3) When I had the ground bar floating, I reattached it over night with just the feeder, LIM and transformer ground wires attached. I left off all the branch circuit ground wires off. I did leave the 3 pieces of equipment plugged in and turned on.....I had over 75 alarms the next morning.

The list is very long of things I have tried. Too long to list. I can say that all the other o.r. rooms a functioning just fine and they are all feed out of the same panel. I did megger the ISO transformer also and that checked out ok. Any thoughts?? Any suggestions?? All is very much appreciated!

 

[Saturn_Europa]

Hello to everyone. I am currently troubleshooting an operating room that keeps going into alarm on the (LIM) line isolation monitor.
This is a brand new room that was up and running for several weeks. Last week they had a bigger case than normal and brought in extra equipment. After the equipment was plugged in it went into alarm. The tech from the hospital went up and unplugged all unnecessary equipment. After that all the problems seemed to have started. The LIM would go from 2.7 milliamps down to .07. This continued throughout the surgery. I was called in to troubleshoot the problem. This is where I am at now with this room. If I plug in 3 particular pieces of equipment that is used daily in these rooms it will drive the LIM monitor into alarm as high as 7-8 milliamps then on its own fall back down to 2.4 milliamps or as low as .5 milliamps. Then on its own will drive right back up into alarm. This scenario will happen all day unless I unplug the equipment. All the equipment has been checked out and has been taken to other o.r. rooms with no problems. After checking all the wiring, plugs, connections ect. there are 3 things that have my attention and looking for some help on this.

1) I removed the ground bar from the isolation panel and had it floating with only the ground wires from the feed, the LIM and the transformer attached. With the bar floating it would go into alarm. If I removed just the ground wire coming from the feed the LIM would drop down to a normal reading and stay there. I put a megger on the feeder wires and all checked out. I even increased the ground wire size and temporary ran it to the ISO panel and still went into alarm.
2) I can only get the ISO panel LIM to fluctuate when I have these 3 pieces of equipment plugged in and turned on. I have tried the same type of equipment from other o.r. rooms and took this equipment to other rooms. The LIM still fluctuates.
3) When I had the ground bar floating, I reattached it over night with just the feeder, LIM and transformer ground wires attached. I left off all the branch circuit ground wires off. I did leave the 3 pieces of equipment plugged in and turned on.....I had over 75 alarms the next morning.

The list is very long of things I have tried. Too long to list. I can say that all the other o.r. rooms a functioning just fine and they are all feed out of the same panel. I did megger the ISO transformer also and that checked out ok. Any thoughts?? Any suggestions?? All is very much appreciated!

This is outside my area of expertise but I will tell you what I do when I cant figure something out:

1. Call the manufacturer of the Line Isolation Monitor.
2. Plug in the equipment one at a time to see if you can isolate the problem down to one piece of equipment.
3. Call the manufacturer of the piece of equipment you are having problems with.


I know its not much of an answer but maybe it will help you get headed in the right direction.

Interesting problem, post back what you find.

 

[mgookin]

This is outside my area of expertise but I will tell you what I do when I cant figure something out:

1. Call the manufacturer of the Line Isolation Monitor.
2. Plug in the equipment one at a time to see if you can isolate the problem down to one piece of equipment.
3. Call the manufacturer of the piece of equipment you are having problems with.


I know its not much of an answer but maybe it will help you get headed in the right direction.

Interesting problem, post back what you find.

Manufacturers want to know these things and they want to help you!

 

[Ponchik]

I don't have any experience with OR or LIM and don't know what the receptacle configurations are for this room. But, just for testing purposes have you tried plugging in something other than medical equipment. (200watt light bulb, a hair dryer, electric drill....)

 

[steve66]

If I plug in 3 particular pieces of equipment that is used daily in these rooms it will drive the LIM monitor into alarm as high as 7-8 milliamps then on its own fall back down to 2.4 milliamps or as low as .5 milliamps.

If this happens in this OR, but not other OR's with similar isolation panels and LIM's, I would say something is wrong with the isolation panel or the LIM.

Call an isolation panel expert.

Once any change is made that might affect the operation of the isolation panel (disconnecting or changing the ground, for example), the panel is supposed to be re-tested before being used again. And the test is supposed to be documented.

 

[steve66]

If I plug in 3 particular pieces of equipment that is used daily in these rooms it will drive the LIM monitor into alarm as high as 7-8 milliamps then on its own fall back down to 2.4 milliamps or as low as .5 milliamps.

If this happens in this OR, but not other OR's with similar isolation panels and LIM's, I would say something is wrong with the isolation panel or the LIM.

Call an isolation panel expert.

There are no surge suppression receptacles or power strips in the OR, correct?

Once any change is made that might affect the operation of the isolation panel (disconnecting or changing the ground, for example), the panel is supposed to be re-tested before being used again. And the test is supposed to be documented.

 

[ghostbuster]

Just a thought

I have worked in a troubleshooting mode for many many hospitals---Lims/Cat Scans/MRI./Xray/Emergency Power etc.

Many times we have found the wiring from one system is by mistake cross-wired with another system--in addition the neutrals are grounded/shared at multiple points in many cases.

It would not surprise me that you may have inherited multiple issues at this site.

Good Luck

 

[plumb bob]

Do you have a problem with the equipment on all the circuits in the panels or just certain circuits? If the equipment sends the panel into alarm on any circuit in the panel I would begin to suspect the electronics in the monitor itself. If it is only on certain circuits within the panel I would begin to check those circuits, looking to make sure it isn't tied together with another isolated circuit or tied together with another general purpose circuit in the OR, maybe the room lights which may not be XHHW wire from the iso panel.

I would also contact the panel manufacturer, they should have a record of the panel from commissioning.

 

[ds124]

Thanks for all the replies.
The manufacturer is involved with this. They did send a tech out to go through the panel and even changed the LIM module. Everything on there end checked out. The engineer has been emailing me with different things to try and everything is still the same. My last email from him was that he is at a complete loss of what is going on here. Yes, I plan on getting commissioning test done again once the problem is solved. The original test checked out with no problems.

There are no surge suppressors in this room but will say that it is acting just like there was one. We had a similar problem in another o.r. when the IT tech installed surge suppressor out of habit on the computer in the room. Once removed everything worked fine.

I did pull out every plug in the room to check connection and polarity. I did not check to see hot or neutral got crossed. Something I will look at tomorrow. This problem seems to exist on any circuit. I was even plugging and unplugging the anesthesia machine. Anesthesia machine has two plugs, one for monitors and one for the equipment. If I unplugged both then put back in monitor plug it would drive the LIM monitor down. (against the normal....monitor should go up when adding loads). Then I would plug in second plug and it would drive the LIM up into alarm.

I have not tried any other electrical equipment that was not related to the o.r.'s Something else I can try.

I have to say, I have 32 years experience in the trade and was the foreman and worked on all 4 of these operating rooms. All new and all the same.....I am running out of ideas. We do have a power quality meter installed on the gear feeding these rooms but not expecting much since the other rooms are working without problems. Keep the suggestions coming!

 

[zbang]

I am not qualified to work on these panels, and this is way out in the blue sky, but have you meggered everything (the feeder is mentioned, branch is not)? I'm wondering if maybe there was some movement, somewhere, that abraded a bit insulation just enough to leak, and that connecting equipment moves it enough to be a problem.

Is there such a thing as a calibrated leakage load (I assume there is). How does the LIM behave with just that? In a pinch, for troubleshooting only, you could easily make one. At 120v, a 25.5k ohm (1%) resistor will draw 4.7ma.

(I find this sort of thing interesting even if I'm not going to work on them.)

 

[steve66]

I am not qualified to work on these panels, and this is way out in the blue sky, but have you meggered everything (the feeder is mentioned, branch is not)? I'm wondering if maybe there was some movement, somewhere, that abraded a bit insulation just enough to leak, and that connecting equipment moves it enough to be a problem.

Is there such a thing as a calibrated leakage load (I assume there is). How does the LIM behave with just that? In a pinch, for troubleshooting only, you could easily make one. At 120v, a 25.5k ohm (1%) resistor will draw 4.7ma.

(I find this sort of thing interesting even if I'm not going to work on them.)

Along the same lines, the electricians didn't use any lubricant when they pulled the wire, did they?

I think they need to replace the entire isolation panel. They may have a bad transformer or something.

 

[roger]

I did pull out every plug in the room to check connection and polarity. I did not check to see hot or neutral got crossed.

There is no polarity to worry about (besides identification) in an Isolated Power System because there is no neutral, it is an L-L system, 60V/60V.

What type of conductors are used?

Roger

 

[roger]

I think they need to replace the entire isolation panel. They may have a bad transformer or something.

I agree

Roger