1

I'm building my own small house in Wyoming. I made a mistake in that I did not run 240V to the kitchen, as my wife said she'd never use an electric stove. She's now shopping for fancy stoves that have 240V/40A electric ovens and gas burners.

First floor is about 700 sq ft, so I put the electrical panel on the exterior to save space. Drywall, paint, and wallpaper are already done. Retrofitting an appliance circuit would be very difficult.

The stove will be against an exterior wall on the first floor. Can I simply run 8/3 UF-B W/G (direct bury) cable from the breaker panel, to the ground, around a corner, and into the exterior wall behind the stove? The run would be <50 ft. The panel is fed aerially; would I need a conduit running down to the ground to protect from sunlight?

6
  • There are fancy stoves with gas tops and combo gas/electric ovens using only 120V. Whoever wants a fancy stove may not want an ugly conduit wrapped around their house, and may be persuaded to look at combo models. :)
    – jay613
    Commented Mar 26 at 17:43
  • Sorry for being unclear! I'm proposing to bury the wire.
    – bendodge
    Commented Mar 26 at 18:00
  • I started writing based on the wire being above ground. But I'd still go with RMC because of burial depth. Commented Mar 26 at 18:13
  • Will still need the conduit down to the ground to protect the cable from weed whackers, baseballs, knives. Conduit not needed in the ground with direct bury cable, but it will need to dug up again if something happens to the cable. Conduit will allow to just pull the wires.
    – crip659
    Commented Mar 26 at 18:13
  • 1
    Ah! For direct burial of UF you would need a conduit from the panel to some distance below ground, I think two feet, and another one back up to where you enter the kitchen wall. Not against sunlight, as UF does not need that, but against damage from humans, lawn mowers, etc.
    – jay613
    Commented Mar 26 at 18:13

1 Answer 1

1

Best bet, by far, is metal conduit with individual wires. There are multiple factors involved:

  • Direct bury cable may not be UV-safe - check the specs - but I trust ThreePhaseEel's comment that UF is UV-safe
  • Any cable between ground and 8' (or so, not sure exactly at the moment and may vary by jurisdiction) that is exposed needs to be protected from physical damage.
  • Direct bury cable normally needs to be 24" deep. Conduit depth varies, but with RMC it is only 6" except under driveways. So the digging is a lot easier.

When most (I think in this case all) of a significant cable run needs to be protected (certain types of conduit or wood or metal covering the cable run) it is generally better to use conduit and individual wires. Typically that means rigid metal conduit, intermediate metal conduit or PVC schedule 80 conduit. Personally, I prefer metal.

With conduit, you have to be concerned with conduit fill. It is a good idea to plan for a bit more than you currently need in order to allow for future expansion. For example, 3/4" RMC has enough capacity for:

  • 3 x 8 AWG copper (40A or even 50A oven)
  • 1 x 10 AWG copper (ground - you can also use the conduit itself as ground, but for a long distance having a true ground wire is not a bad idea)
  • 3 x 12 AWG copper (20A MWBC - lets you add 2 x 120V circuits for receptacles or microwave or refrigerator or whatever) - if you don't need these circuits now, you can leave the wires out and add them later when you do need them.

There are limits though - once you get past 2 or 3 circuits you get into derates based on the number of wires that can require upsizing everything.

1
  • 2
    UF cable is UV-safe (it can even be strung on a messenger wire) Commented Mar 27 at 3:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.