I know I can run indoor wire underground as long as it is protected in something, but can I use a water hose to run it through instead of conduit or PVC?

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    What is "water hose", and why are you avoiding doing the project to code? – isherwood Jul 24 '18 at 14:50
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    Absolutely horrible idea. Do not do it. – The Evil Greebo Jul 24 '18 at 14:59
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    Agree its a bad idea but its a good question - always best to ask if you're unsure. Welcome to home improvement where you're always welcome to ask more questions to double check before you carry out a job! :) – Lio Elbammalf Jul 24 '18 at 15:07
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    Yes please don't let the harsh response drive you off. It's GOOD to ask these questions! – The Evil Greebo Jul 24 '18 at 15:12
  • I'm wondering if "water hose" means pex. I actually did this when running some UV cable to a yard shed because I had some laying around. – isherwood Jul 24 '18 at 16:07

You can't actually use indoor wire underground. The wire or cable will get wet, will degrade, leak, and do really strange things like electrify the ground. There is nothing you can do to keep conduit dry. It will get wet.

In legit conduit, normally you use individual wires (THHN). Almost all THHN is dual-rated THWN-2 for outdoor use! Same wire - that was easy! I work in THHN/THWN-2 and I love it.

enter image description here

Note the two layers of insulation.

Some homeowners are super obsessed about using cable instead of wires. That's silly in (legit) conduit! However it can be direct buried. Indoor cable (NM) is indoor-only and gets wrecked fast in the outdoors, in that case you'd need outdoor-rated cable such as UF.

Bad NM: enter image description here ........ Good UF: enter image description here

Barely seen: paper packing in the NM cable.

If you ever plan to sell the property, you need to do this right. Part of the home sale process is inspections. Any not-to-code work must be ripped out and replaced (pulling permits for both the demo and the replacement, so they'll know). Once you are caught, secretly removing the work won't be an option anymore.

You can't use any random pipe-like thing to run electrical cables. Well, you can, but it doesn't count as conduit. So the only thing you can run through water hose is UF or other outdoor rated direct burial cable, and the installation will be treated as direct burial.

Also when you bury it, the garden hose will collapse, so you won't be able to pull that wire out and change it, if that's what you were thinking.

Random cheap PVC also doesn't work as conduit - only the gray electrical rated stuff qualifies as conduit. Using white plumbing PVC is just a bad idea, it'll get hung up on every joint and won't make the bends.

You can also use metal conduit, it's not expensive if you shop around and buy it somewhere other than the big-box store.

There are depth requirements for how deep you bury it.

  • For expensive RIGID conduit it's 6".
  • For a single circuit GFCI protected, it's 12" direct burial or conduit.
  • For other legit conduit, 18".
  • For other direct burial (or fake conduit), 24".

In all cases that's the amount of earth above the top. Don't trench a 6" trench and put 3" RIGID into it leaving only 3" of dirt above it.

  • What is the purpose, then, of conduit? Is it only to protect from physical damage? – Michael J. Jul 24 '18 at 18:18
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    @MichaelJ. Also a grounding path (if metal), enabling use of easier-to-wield THHN instead of stiff cables, enabling easy circuit adds, enabling easy wire upsizing, and allowing your trenching to be shallower. There may be more, that's what I could think of in 1 minute. – Harper - Reinstate Monica Jul 24 '18 at 18:24
  • Doesn't the US use SWA cable for this sort of thing? – Martin Bonner supports Monica Jul 25 '18 at 14:00
  • @MartinBonner yes, the US has a variety of direct burial cable. The linked cable would be odd by US standards since it has a green/yellow ground wire wrapped by a metallic shield. In the US, ground wires cannot be reassigned to other purposes, so the dual ground would be redundant. – Harper - Reinstate Monica Jul 25 '18 at 15:11
  • The shield is not (necessarily) a ground. I know enough to know that (safe) grounding of (eg) sheds is complicated - but not enough to summarize the rules in this comment. – Martin Bonner supports Monica Jul 25 '18 at 19:12

Sure, you can...but as far as whether you should then no.

I know its probably not what you're thinking of at the moment but in the future, among other problems, someone digging around in the garden and spotting a buried garden hose might not think of it holding electrical cables.

I'd recommend twin walled cable ducting, its not overly expensive and better protects both your cables and anyone who might come across them in the future. Its always better to do something properly rather than cheap.

(Also if you sell the house I'm pretty sure a surveyor would check this and not be overly positive about your choice).

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    PVC conduit is not terribly expensive and failing to follow code when working with electrical lines is negligent to the point of putting people at risk. You can't easily cut through conduit with a garden shovel - but a garden hose will slice into it easy. ZAAP. Don't take risks that could kill someone. – The Evil Greebo Jul 24 '18 at 14:58
  • Did you mean garden hoe? Even schedule 40 can stand up to a fair amount of damage my hand tools. – Ed Beal Jul 24 '18 at 16:24
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    @EdBeal I'm not sure about the phasing, but I think the intent was "a garden shovel can't easily cut through conduit, but will easily slice garden hose." – Joshua Taylor Jul 24 '18 at 19:49
  • Ok thanks I read it several times, I had forgotten the op mentioned using a garden hose+ – Ed Beal Jul 24 '18 at 19:55

You can bury wire outdoors as long as you use Direct Burial wire. It is readily available from many sources.

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