Nov 22 2017

Cable Attached to the Outside of Conduit

Category: Conduit,Questions and AnswersBKeyes @ 12:00 am
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Q: I am being told by a building engineer that low voltage cable cannot be attached (i.e. wire-tied) to existing conduits in the hospital. In ten-plus years in this business I have never heard of this being a problem. Is there any way to confirm this is a code violation?

A: Yes, I’m afraid this is true. Section 19.5.1.1 (section 18.5.1.1 for new healthcare occupancies) of the 2012 Life Safety Code requires compliance with section 9.1 which in turn requires compliance with NFPA 70 National Electrical Code, 2011 edition. Article 300.11 (B) of NFPA 70 does not permit anything to be attached to conduit, with one exception: Class 2 control cable may be attached to the conduit if it serves the circuit in the conduit.

Apparently, the concern that NFPA has is heat from the electrical conductors inside the conduit may not dissipate adequately if there are additional cables and wires tied to the outside of the conduit. While it is highly unlikely that a single low voltage cable that is wire-tied to a conduit would cause a problem, I guess it is logical that many wires and cables could be a problem. The question is where do you draw the line? I guess NFPA draws the line at one (1). So, I’m sorry to say, you will have to remove all the wires and cables from conduits in order to be compliant with the LSC. And by the way, do not attach those wires to your sprinkler pipes, either. That will cause a whole bunch of problems that you don’t need.


Dec 30 2016

Cables Strapped to Conduit and LIM Testing

Category: Conduit,Line Isolation Monitors,Questions and AnswersBKeyes @ 12:00 am
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Q: Can fiber optic and low voltage cables be attached or strapped to conduit? Also, what certification is needed for individuals who perform the annual line isolation monitor (LIM) tests in operating rooms?

A: No, cables and wires are not permitted to be strapped to conduit, unless the cables or wires control the circuit inside the conduit. This is a huge problem in many hospitals as many facilities did not adhere to article 300-11(B) of the 2011 NFPA 70 National Electric Code requirement for many years.

To answer your second question, I reviewed article 517-160 of NFPA 70-2011, on Isolated Power Systems for healthcare, and I did not see anything that required any level of training, certification or licensure for individuals conducting tests on LIM.

I also examined NFPA 99 Health Care Facilities Code, 2012 edition, and according to sections 6.3.3.3.2 and 6.3.4.1.4, LIM must be tested after installation, then monthly; or every 12 months if the LIM is equipped with automated self-test and self-calibration capabilities. Nowhere in this document does it discuss the requirements for the individual performing this test.

Perhaps there may be another code or standard that specifies the requirements for testing, but I did not find it. I suggest you ask your state or local AHJs to see if they have any requirements that must be adhered to.