I have to install individual isolated ground cables (#6awg) to each IDF closet from the service electrical ground point and install an isolated ground bar. These cables will be run above a plenum ceiling. What type of isulation would be required to be used on these cables?
Isolated
- Thread starter quentman
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- Illinois
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- retired electrician
Re: Isolated
See 300.22(C)(1). You will have to find a conductor listed for the use or intall it in a metallic raceway. The problem with the raceway would be that you have to bond the conductor to the raceway at each end which would defeat the intended isolation.
Don
See 300.22(C)(1). You will have to find a conductor listed for the use or intall it in a metallic raceway. The problem with the raceway would be that you have to bond the conductor to the raceway at each end which would defeat the intended isolation.
Don
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Isolated
Don would he be required to run this ground with the circuit conductors? and If not could he run a bare copper #6 on ceramic insulators as there would be no plastic to cause smoke?
Don would he be required to run this ground with the circuit conductors? and If not could he run a bare copper #6 on ceramic insulators as there would be no plastic to cause smoke?
- Location
- Illinois
- Occupation
- retired electrician
Re: Isolated
Wayne,
The bare copper would work fine. I'm not sure what a "IDF" is, but I assumed that it was some type of communications equipment and that this ground is not part of a power circuit. If the ground is part of a power circuit, it would have to be run, as you said, with the circuit conductors.
Don
Wayne,
The bare copper would work fine. I'm not sure what a "IDF" is, but I assumed that it was some type of communications equipment and that this ground is not part of a power circuit. If the ground is part of a power circuit, it would have to be run, as you said, with the circuit conductors.
Don
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Isolated
I think it has to do with the airport so the planes can find it. but could be anything.
I didnt know that it would have to be bonded to the race-way in this type of instaltion as the conduit would only be for a sleave to get through the plentium? and even for isolated receptacles you dont have to bond the insulated ground wire except at the panel or it wouldn't be isolated anymore. couldn't you bond the race-way with another wire back to the panel? or even if you ran the emt back to the panel wouldn't that count?
I think it has to do with the airport so the planes can find it. but could be anything.
I didnt know that it would have to be bonded to the race-way in this type of instaltion as the conduit would only be for a sleave to get through the plentium? and even for isolated receptacles you dont have to bond the insulated ground wire except at the panel or it wouldn't be isolated anymore. couldn't you bond the race-way with another wire back to the panel? or even if you ran the emt back to the panel wouldn't that count?
Re: Isolated
IDF I believe stands for Intermediate Distribution Frame since he is talking about being in closets. It is a communications term used to describe a wiring distribution frame for telecom wiring such as CAT-X, coax, ABAM, etc..
If the ground bar is used for termination of cable protectors, cable shileds, or frame grounds, there should be no need to keep it isolated. It should go to the nearest availible ground electrode.
On the other hand, if it is used as a signal ground, it should be ran isolated back to the power source ground bar. The power source may or may not be the service entrance, it could be a DC plant, converter, isolation transformer, or sub-panel. In a plenum enviroment you can use a Teflon (TFE) insulated cable if you can afford it, or you can use conduit. If conduit is used you would need to isolate the conduit from incidental contact with building steel or concrete by mounting it on isolation cherries. Once the conduit is isolated you can bond the ground conductor at both ends to prevent choking and satisfy NEC requirements.
Dereck
[ April 26, 2003, 04:16 PM: Message edited by: dereckbc ]
IDF I believe stands for Intermediate Distribution Frame since he is talking about being in closets. It is a communications term used to describe a wiring distribution frame for telecom wiring such as CAT-X, coax, ABAM, etc..
If the ground bar is used for termination of cable protectors, cable shileds, or frame grounds, there should be no need to keep it isolated. It should go to the nearest availible ground electrode.
On the other hand, if it is used as a signal ground, it should be ran isolated back to the power source ground bar. The power source may or may not be the service entrance, it could be a DC plant, converter, isolation transformer, or sub-panel. In a plenum enviroment you can use a Teflon (TFE) insulated cable if you can afford it, or you can use conduit. If conduit is used you would need to isolate the conduit from incidental contact with building steel or concrete by mounting it on isolation cherries. Once the conduit is isolated you can bond the ground conductor at both ends to prevent choking and satisfy NEC requirements.
Dereck
[ April 26, 2003, 04:16 PM: Message edited by: dereckbc ]
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