When entering a building, what is the rule for the non-plenum rated OSP cable if it travels over 50ft??? Does it have to be in RMC? Is EMT or plenum rated innerduct accecptable? What if it is a fiber optic cable - nonconductive vs. conductive (i.e. an armored layer in the jacket)?
800.50 OSP entrance cable 50ft rule???
- Thread starter billm
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- Illinois
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- retired electrician
Re: 800.50 OSP entrance cable 50ft rule???
Conductive optical fiber cables must be in rigid or intermediate metal conduit if the length inside of the building exceeds 50'. Nonconductive optical fiber cable can be installed in any Chapter 3 raceway. See Exceptions 2 and 3 to 770.50.
For communications cables, you can run 50' or less in the building provided that "terminated in an enclosure or on a listed primary protector". If it is not terminated as above, then it must be "continuously enclosed in a rigid metal conduit system or an intermediate metal conduit system". See Exceptions 2 and 3 to 800.50.
Don
Conductive optical fiber cables must be in rigid or intermediate metal conduit if the length inside of the building exceeds 50'. Nonconductive optical fiber cable can be installed in any Chapter 3 raceway. See Exceptions 2 and 3 to 770.50.
For communications cables, you can run 50' or less in the building provided that "terminated in an enclosure or on a listed primary protector". If it is not terminated as above, then it must be "continuously enclosed in a rigid metal conduit system or an intermediate metal conduit system". See Exceptions 2 and 3 to 800.50.
Don
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
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- EC
Re: 800.50 OSP entrance cable 50ft rule???
...non-plenum rated OSP cable
No such thing as an OSP cable with ANY listing. That's why it's outside plant cable- it's not for use in a building.
Keep in mind also that the primary protectors must be located as close as possible to the point of entrance, which should be with the electrical service equipment, so the grounds can be bonded with the shortest possible grounding conductor. If this is maintained then long runs of OSP cable within the building would not be required.
...non-plenum rated OSP cable
No such thing as an OSP cable with ANY listing. That's why it's outside plant cable- it's not for use in a building.
Keep in mind also that the primary protectors must be located as close as possible to the point of entrance, which should be with the electrical service equipment, so the grounds can be bonded with the shortest possible grounding conductor. If this is maintained then long runs of OSP cable within the building would not be required.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: 800.50 OSP entrance cable 50ft rule???
I don't see any prohibition against it but that could be because nobody ever considered doing it. Why would it would need to be run that far vertically when the entrance protectors should be close to the other service entrances which undoubtedly would not be on the 4th floor of a building.
If it's only one floor, like in through the foundation then up through the floor, that's done all the time.
[ February 07, 2004, 03:14 PM: Message edited by: hbiss ]
I don't see any prohibition against it but that could be because nobody ever considered doing it. Why would it would need to be run that far vertically when the entrance protectors should be close to the other service entrances which undoubtedly would not be on the 4th floor of a building.
If it's only one floor, like in through the foundation then up through the floor, that's done all the time.
[ February 07, 2004, 03:14 PM: Message edited by: hbiss ]
Re: 800.50 OSP entrance cable 50ft rule???
[ February 07, 2004, 04:09 PM: Message edited by: dereckbc ]
If it is fiber-optic cable, what protectors? The only requirement/practice is to bond the metalic strength member or shield where it enters. The only protectors I have ever specified for fiber cable is if locating equipment is used in the installation.
[ February 07, 2004, 04:09 PM: Message edited by: dereckbc ]
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