Raceway vs Residential Branch Circuit

[Gvndual]

NEC table 300.5 Column 3 says something about raceways needing to be buried 18”, but column 4, residential branch circuits, only need to be buried 12”. What’s the difference?
I am burying romex inside of PVC for the pool pump. 680.11 says, “...underground wiring shall not be permitted under the pool unless this wiring is necessary to supply pool equipment permitted by this article. Minimum cover depths shall be as given in table 300.5.

So, 12” or 18? Thanks.

Intex Ultraframe 32x16x52”, 70110 sand filter pump

 

[ChrisNC]

First issue I read is Romex in conduit. Romex isn't rated for wet locations.

As far as 12" or 18" - Will your circuit be 20 amp or less and have GFCI protection?

 

[Gvndual]

Yup, just found out that romex is considered “NM” and can’t be buried inside of Schedule 40 pvc. My circuit is 20 Amos and has gfci at the house, directly off the CB panel on a new cb installed for the pool, and from which the THWN or UF-B will be run (terms I just learned today). Also, I can’t find wire at any of the “big box” stores that are listed as THWN. Should I just buy UF-B and run it through the PVC? And the local inspector says it can be at 12”. Is that true?

 

[ogdento]

(i am not an electrician) I would use THHN. UF-B is intended for direct burial but I believe you can run it in conduit for protection (when conduit is for protection I believe it is not considered a raceway), it's just more expensive than THHN...

THHN is suitable for wet or dry locations and I think most THHN available is actually dual rated for THHN/THWN. If you were looking at a Southwire product at a big box store maybe there's some fine print on the label somewhere that mentions THWN?

In any case, here's a link to a Southwire spec sheet that says their THHN is dual rated:
https://images.homedepot-static.com/catalog/pdfImages/2c/2c1c89d6-76f9-4f97-878f-4ffd9fa31f2a.pdf

But if you want to be extra sure you may be able to get a manufacturer code off the big box label and look it up on the Southwire site.

 

[danpik]

UF-b is not code compliant for pools either as the ground wire needs to be insulated and the sheathing on "romex" type cables is not considered electrically insulating. You should be able to buy the wire by the foot ( Black, White, Green) at any big box store https://www.homedepot.com/p/Southwire-By-the-Foot-6-Black-Stranded-CU-SIMpull-THHN-Wire-20493399/204632784
or from an electrical sypply house near you.

Dan

 

[danpik]

UF-b is not code compliant for pools either as the ground wire needs to be insulated and the sheathing on "romex" type cables is not considered electrically insulating. You should be able to buy the wire by the foot ( Black, White, Green) at any big box store
or from an electrical supply house near you.

Dan