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What is the best way to bury a wire from the house to the shed? Answered

I am planning to wire my shed for lighting and working with tools. My question is which is the best way to protect the wire that is going to be buried in the yard. What type of conduit should I use? Is there an underground conduit for cases like this?



Best Answer 8 years ago

Yes, there is underground conduit which is required for cases like this.  Any big hardware or "home improvement" store (like Home Depot) will carry it.  It's usually grey PVC, threaded, with threaded connectors, elbows, etc. 

You'll want to bring the line at the shed into a breakout box with a cutoff switch or circuit breaker, before distributing the internal wiring.  I've seen people use a simple GFCI outlet for the purpose (in series with the lighting), but I am not sure that's up to code.

.  If you are going to use plastic pipe (which provides next to no protection from shovels), why not just use direct burial cable?
.  Or use steel/iron pipe.
.  I'm not sure what the NEC calls for, but I'd put the GFCI breaker in the house breaker panel. If something happens to your cable (eg, varmint chews through insulation), the GFCI will start tripping. YMMV.
.  If in an area of the country that actually enforces the electrical code, get a qualified Electrician to do the job.

You've got it...damn, I missed all the good ones today :P

Building code is a huge concern - in freezing environments it has to go below the frost line, various wet/dry locations need specialty connectors with goopy threads.  Sometimes the trench needs drainage...

As you say, it is the best plan to run heavy gauge wire from a dedicated fuse in the house to a panel in the garage, with fuses for each application.

be sure not to "pull" romex or other grouped wires through the conduit. this can cause over heating. use what is called THHN wire. for a 110/125 amp single pole circuit this is one each, black, white and green. for a 220/250 amp circuit this is one each, black, red, white and green. green is ALWAYS a ground wire and white is ALWAYS a neutral. if you will be "pulling" more than one circuit in your conduit make sure to check the "fill" rating and not overload the conduit.

Sorry killer, burying cables along a fence is the perfect way to have it accidently dug up. You never know what a neighbour might do close to his side of the fence as far as digging/gardening/shed building etc. Fences also need to be replaced sometime, and even if the cable is the correct depth, a fencing contractor with a motorised post hole digger will tear up even the strongest metal conduit.
Underground rated plastic conduits last longer than steel, and the joints can be glued to exclude moisture. The best way to know where your underground wiring is, is to run it in a straight line from the point which it leaves your house to the point where it enters your shed, then if you need to dig you can always plot a line. Also put about 6" of dirt over your conduit then lay a line of bricks or paving stones so that if anyone digs them up they know there may be something underneath. Sand is also good as it is suddenly noticeable when the dirt changes colour while you are digging.
Electrical cables in conduit are allowed to be buried directly beneath or within concrete wher I live. Maybe run it under a pathway?

They actually make tape (tape like "police line do not cross") for this application.

I like the bricks/sand idea too.

Do your best to bury it per your building codes.  I just ran mine from house to garage above the ground high up where it was out of the way.  That worked ok until i sold the house. then inspector made me PAY an electrician to do it professionally.  I could NO LONGER do it myself because house was under the scrutiny of inspectors and etc.  due to selling it.  I had to pay $800.00 for this little 30 foot long wire buried under ground to the garage! I could have done it myself for very little money.

As said by others, underground conduit or the rated cable, if there's a fence or wall nearby following close to it will help with worries of accidentally digging the wire up later... 

If this is in the US, you can bury wire rated for direct burial 18" deep with out putting in conduit.  I know this to be true cause I just got a line run from my house to my tractor barn.  I've got rocky soil and it couldn't go that deep so it cost me $500 extra for conduit.

Which ever way you go I suggest you bury a warning tape over the line, like plastic caution tape, so that if you or the next owner digs they will see the tape and realize there is something down there.