Type "DB" conduit

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DB 120 is what my local POCO & Telco use for there service conduits, it is thin. In a previous thread it was pointed out the (except for POCO work) you can only use it as a "sleeve" and put direct burial cable in it.
 
I should add it works fine if you are careful not to stress it, and most of the time you need to concrete the elbows or they are toast on the pull. The couplings fit both sch.80 through P&C so adapting to a heavier conduit coming out of the ground is easy.
It is not a NEC recognized though, only POCO.
 
I am reviewing a set of drawings where DB is specified for underground runs.

I wanted to be sure this is a violation before I tell them they have to use Schedule 40.

I don't think there is anything that says a conduit has to be UL listed, but I don't think this stuff is a Chapter 3 wiring method either.

Steve
 
352.6 Listing Requirements. PVC conduit, factory elbows, and associated fittings shall be listed.

We use anything that we have found to be safe. :smile:
 
schedule 20 pvc thread

schedule 20 pvc thread

yes 352.6 states that the materials used have to be listed, but listed as defined in the NEC refers to product testing and QC of products, as in UL listings. Where in the NEC is reference stating that you cannot use materials, such as schedule 20 pvc, that are not listed in the NEC, as in "not in the text". Schedule 40 and schedule 80 are listed and referred to in the NEC of course, which means they are an approved material for line voltage electrical wiring installations. Schedule 20 however is not mention, listed, or referred to in the NEC, therefore it is not an approved material for use, but where is the code reference that would back that up?
 
traveler.com said:
yes 352.6 states that the materials used have to be listed, but listed as defined in the NEC refers to product testing and QC of products, as in UL listings. Where in the NEC is reference stating that you cannot use materials, such as schedule 20 pvc, that are not listed in the NEC, as in "not in the text". Schedule 40 and schedule 80 are listed and referred to in the NEC of course, which means they are an approved material for line voltage electrical wiring installations. Schedule 20 however is not mention, listed, or referred to in the NEC, therefore it is not an approved material for use, but where is the code reference that would back that up?
Click to expand...
The product has to be listed as PVC conduit. The schedule 20 stuff is not so listed.
 
i was on a large underground job in San Diego (all utility) and all we used was 20 foot sticks of DB 40 and DB 80

the only thing i remember about it being weak was if you dropped it off in the ditch (6 or 7 foot drop, sometimes the bell ends would crack...

that was the best looking underground i have ever seen...


that hill.... you could barely crawl up it
 
300.6 who is to say schedule 20 pvc is not suitable.
Article 100
Definitions
Approved: acceptable to the authority having jurisdiction

still no solid reference from NEC to say it cannot be used!
 
An AHJ can "approve" installations. Most AHJs I know will not approve many installations that are not incorporating listed products, especially when listed products for the application are readily accessible.

Following the requirements of 300.6 are relatively easy, and if it is not a POCO installation, those are the requirements I will follow as well.
 
traveler.com said:
300.6 who is to say schedule 20 pvc is not suitable.
Article 100
Definitions
Approved: acceptable to the authority having jurisdiction

still no solid reference from NEC to say it cannot be used!
Click to expand...
The code rule in 352.6 does not call for the use of an "approved" product. It calls for the use of "listed PVC conduit". The schedule 20 PVC tubing is not so listed.
 
The handbook says that EB-20 is recognized as PVC in the notes. I know the OP was talking about DB but the thread wound it's way to "20". Theres a few different flavors of "20"
 
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