ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Topic Options
Rate This Topic
#24120 - 04/04/03 03:38 PM Lim's
Weekend Offline
Junior Member
Registered: 03/27/03
Posts: 3
Loc: Missouri
I'm an electrician in a hospital that wants to remove rather than replace or repair Lim's. Personally I think it's a mistake but they are not required except in designated "wet locations". Since the panels are not grounded (obviously )and the breakers are 2 pole it would mean installing new panels or fewer panels of larger capacity. Any thoughts?
Top
Work Gear for Electricians and the Trades
#24121 - 04/04/03 05:23 PM Re: Lim's
Roger Offline
Member
Registered: 05/18/02
Posts: 1716
Loc: N.C.
How old is this installation? All modern Isolation installations use brown, orange, and yellow. This would mean that all the circuits would have to be rewired .

What is the primary voltage to the transformers? This could mean alot of work if new feeders have to be routed to your new panels. In any case, in the very least you would have to pull a second ungrounded conductor or a neutral, (what ever the case may be) even if the existing conduit could be used.

If these are going to serve patient care areas, you will have to retest the grounding system in these rooms.

These are just some of the things I see might be problems.

In reality, if these Iso systems are not needed or required by any local or state amendment, I can see doing away with them. For these to be in service you have to do the yearly testing and problem solving periodically or as you said repairing.

Roger

[This message has been edited by Roger (edited 04-04-2003).]
Top
#24122 - 04/04/03 11:48 PM Re: Lim's
Trumpy Offline


Member
Registered: 07/05/02
Posts: 8211
Loc: SI,New Zealand
Weekend,
(What a cool name!)We all look forward to these!!
Welcome to ECN, mate.
BTW, what is a LIM?
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin
Top
#24123 - 04/05/03 12:46 AM Re: Lim's
Roger Offline
Member
Registered: 05/18/02
Posts: 1716
Loc: N.C.
Trumpy, LIM stands for "line isolation monitor". these are used to monitor the leakage and overall impedance of each line (usualy 5ma alarm level) of our health care isolation systems.

Roger
Top
#24124 - 04/05/03 12:50 PM Re: Lim's
Weekend Offline
Junior Member
Registered: 03/27/03
Posts: 3
Loc: Missouri
Lim's are 5-20 years old. Newest might be color coded. Yeah, brown,orange and yellow don't work on 120v..
Primary voltage on most if not all is 120 volts. Management(!) is under the impression that we can simply remove the monitors and ground the secondary. Then again that's why they are management they would be dangerous with tools. I see removing the isolation panel, transformer and monitor (all in an enclosure) at each location and rewiring that location if the raceway can handle it. If not we run new conduit. Since they are not required the NFPA and my local inspector had no problem with me removing the monitors. But it seems that anything less than rewiring would be subject to violation of UL. Not a good thing. Isolation transformers are built and installed for a specific purpose and I'm thinking any deviation is wrong if not illegal somewherer down the road. Yup, it's my license and butt I'm looking out for besides proper electrical work.
All input welcome.
Top

Member Spotlight
Member Since: 02/23/13
Posts: 204
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
0 registered (), 54 Guests and 9 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 49
HotLine1 43
gfretwell 18
Ruben Rocha 12
Trumpy 9
 
Newest Members
Freecrowder, clee512, Jdscott2005, FAIZAN, Regitest2

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals