Underground Fiber Optics Help!

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hamhr

Member
I am not sure this is the correct forum for this question but would appreciate help. I am coordinating a large Premise Wiring job for our company.

As part of this job I need to connect two buildings appox 250' apart with Fiber Optics cabling. I am in dispute with the property manager regarding code requirements. There is an existing underground PVC Conduit which is thin-wall (much less then Sch. 40) that is on average 16" to 20" deep including under a high traffic driveway area.

I have contended that neither the conduit nor the depth are to code, especially when you mix the thin wall with the driveway. My interpretation of the NEC (yes our municipality uses the NEC with no relevant modifications)is driveways are 24" min. no matter what 0v to 600v. And although I haven?t chased down the NEC approval stamps for the conduit I doubt any thin wall is to code.

I would appreciate any help ASAP. The 2002 NEC is vague when it comes to outdoor Fiber Optics.

[ June 03, 2003, 09:48 AM: Message edited by: hamhr ]
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: Underground Fiber Optics Help!

770.3 says that Table 300.5 does not apply to fiber optic installations. 770.6 requires that the raceway be a Chapter 3 raceway and installed per the raceway article. The thin wall PVC is commonly used for underground utility communications installations, but it is not a Chapter 3 raceway.
don
 

hamhr

Member
Re: Underground Fiber Optics Help!

Don,
Thanks for the reply. Can you point me to the proper section(s) of Chapter 3 that defines a Thin Wall PVC Conduit as not being "a Chapter 3 raceway"
 

tom baker

First Chief Moderator
Staff member
Re: Underground Fiber Optics Help!

I think what Don meant was thin wall (Sch 20) is a product used by a utility and is not subject to the NEC - where he stated "underground utility communications"
You'll have to use a Chapter 3 raceway.
 

hamhr

Member
Re: Underground Fiber Optics Help!

Don/Tom,
Do you feel that Article 352 covering Rigid Nonmetallic Conduit covers the underground requirements of the existing raceway? I am currently looking at Section III 352.100 Construction to try to show Sch 20 isn't acceptable for underground PVC raceways.

Tom, are you implying Sch 20 PVC cannot be used to comply with any Chapter 3 raceway specification?

Thanks for your time by the way, it is frustrating knowing Sch 20 at 16 to 18 " below a commercial driveway is not good practice and then seeing standard burial practice don't apply to Fiber Optics. I am put to the task of standing being my connection between buildings and just can't sleep at night putting business critical communications in sch 20 PVC which is 18" below driveway and about a 4" below dumpster pad in direct contact with slab and is already been damaged several times and is oval as you can imagine.

Is there any other catch you can think of such as service entrance into building being Sch 80 or backfill requirements I might be able to fall back on?

[ June 03, 2003, 09:49 AM: Message edited by: hamhr ]
 

tom baker

First Chief Moderator
Staff member
Re: Underground Fiber Optics Help!

Sch 20 is not a listed product for a NEC applications. Look at a stick of sch 40 pvc and the printing on it.

There may be local codes you could look into. In Washington state the telecom service entrance conduit type is restricted also I belive Art 800 may also restrict it to certain types
 
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