FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

Burying electric cable

roughcut | Posted in Construction Techniques on June 17, 2009 07:57am

I am installing a pond fountain and need to bring electric to the pond edge. I will trench a line from the house to a waterproof receptacle. the question is should I bury the 12ga NM wire inside flexible gray conduit or go with NMWU cable without conduit. The cable will be traveling thru some pretty juicy territory before terminating at the receptacle box.

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. Stuart | Jun 17, 2009 08:39pm | #1

    Regular NM wire, or Romex, is not rated for use underground even if it's in a conduit.  You could run conduit and install individual THWN wires, or use the direct bury NMWU stuff.

    1. btuftee | Jun 17, 2009 08:49pm | #2

      Personally, I would never direct bury, always run conduit if you can. You never know when you'll want to run something else in that same conduit. If I recall, you can direct-bury 12" deep if you're feeding with a 15 or 20A, 120V GFCI-protected circuit. Otherwise, it's 18" deep in PVC, and 24" deep for regular direct-burial. I'd have to flip open the code to double-check those figures, but I think that's accurate. So, if you went to PVC conduit instead of a direct bury 120V GFCI line, it's only another six inches of digging.

  2. webted | Jun 17, 2009 10:48pm | #3

    I've done these sorts of set-ups both ways: direct bury and in conduit. For a relatively low load like a pond fountain (let's be clear: I'm talking ~1 amp @ 120V when I say "fountain") I'd just run NMWU. You cannot use NMWU in conduit for the run, but you do need to use conduit or a similar protection for the cable as it comes up to the receptacle head.

    If you were running a pond PUMP (my current pump runs ~4amps), lighting, a UV clarifier, etc.. I'd spend the time and effort and run THWN in conduit.

    In my experience, getting involved with a water feature is addictive, and you end up wanting more/bigger/etc... in short order.

    Once you've stripped the ends off a few lengths of NMWU, you come to appreciate the ease of working with THWN - and also the resistance of NMWU to damage!

    -t

  3. User avater
    BillHartmann | Jun 17, 2009 11:07pm | #4

    It appears that in Canada. I am guess that with the reference to NMWU.

    To the others that is a reference to a direct burial, wet cable that is similar, but I don't think that it is identical to the UF, underground feeder, used in the US.

    So the other comments about burrial depth might be different also.

    "pretty juicy territory "

    Vas is das?

    Do you mean swampy?

    .
    William the Geezer, the sequel to Billy the Kid - Shoe
    1. roughcut | Jun 17, 2009 11:23pm | #6

      Thanks for your input. I have worked with NMWU and yes it is no fun stripping off the insulation, but it does give me heart that the stuff is pretty bullet proof. I guess I will run with that stuff w/o conduit (except as stated, where it come out of ground). The pond is very boggy at the edges and I am sure I will run into water as I trench. I believe the NMWU will resist the water and wet conditions best.

      1. JTC1 | Jun 18, 2009 01:08am | #7

        >> I believe the NMWU will resist the water and wet conditions best.<<

        This must be a very serpentine path this circuit must run since I cannot believe that NMWU will surpass the water resistant properties of rigid PVC conduit with properly glued up and cured joints and fittings.

        You know you can bend it with relative ease and it has a fair amount of flex in small diameters (1/2" & 3/4") even without adding any heat.

        If you have a shop vac, string and a sammich bag - you don't even need a fish to get THWN into the conduit.

        Hit a PVC conduit with a shovel and you most probably have a nick but no penetration, hit NMWU and you may have a hole in the outer jacket. Easier to fix the PVC. 

        Maybe I should go check on my PVC household drains, the traps especially since they are wet 24/7........

        Jim

         Never underestimate the value of a sharp pencil or good light.

        1. User avater
          BillHartmann | Jun 18, 2009 02:31am | #8

          Buried conduit is a wet place anyway. While it might be "sealed" from ground water in most climates moist air will get into it and condensate..
          William the Geezer, the sequel to Billy the Kid - Shoe

          1. JTC1 | Jun 18, 2009 03:02pm | #9

            Understood.

            I am still heavily biased toward conduit for underground runs.  Dug up a few too many UF and direct burial service runs which "will never get hit".

            Appears that many folks seem to "lose their ruler" when burying cable, especially the lighter UF runs such as this one.

            JimNever underestimate the value of a sharp pencil or good light.

  4. WayneL5 | Jun 17, 2009 11:20pm | #5

    Flexible conduit should not be used for burial.  You should use schedule 40 or schedule 80 PVC or schedule 40 steel.  No flex conduit.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Two Ways to Test Windows

New devices showcased at the Builders' Show make it easy to measure glass performance, u-factor, SHGC, window thickness, and more.

Featured Video

How to Install Exterior Window Trim

Learn how to measure, cut, and build window casing made of cellular PVC, solid wood, poly-ash boards, or any common molding material. Plus, get tips for a clean and solid installation.

Related Stories

  • Podcast Episode 695: Saving Bricks, Cut-and-Cobble Insulation, and Waterproofing Foundations
  • FHB Podcast Segment: Waterproofing Below-Grade Foundation Walls
  • Midcentury Home for a Modern Family
  • The New Old Colonial

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 333 - August/September 2025
    • A Practical Perfect Wall
    • Landscape Lighting Essentials
    • Repairing a Modern Window Sash
  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data