I suppose this isn't really directed toward an electrical question, but I thought this might be a good place to ask it, since you guys have all helped me so much with my electrical needs!

I dug a 24" deep trench for my underground feed to my detached garage. The conductors are encased in PVC conduit.
Then, I thought, "I have this perfectly good ditch, why waste it with only the feeder conductors?"

Anyone have some good ideas for what else I could run to my garage, using this trench? Maybe you might have some ideas that I would never even think of. I really want to make my garage a home-away-from-home. A place of refuge, if ya get my drift. A place with all the comforts of home. (wife not included)

Seems a shame to cover the ditch without using it to it's full potential.

Okay, thanks in advance for any ideas you share.

 

At a separation of at least one foot horizontal, run a second conduit. At a later time if you want you can then run anything you want through it.

 

And through the second conduit you can run 2 or 3 CAT6 cables, speaker wires, video wire, 2 cable wires.

Overkil, probably but you never know...

 

> Anyone have some good ideas for what else I could run to my
> garage, using this trench?

Nothing. It is too shallow for water lines.
Nothing else is really allowed.

You could put in 6-12" of fill, then run a conduit for low voltage or communications lines offset to the one side.

> Seems a shame to cover the ditch without using it to
> its full potential.

Electric goes in a trench by itself. That is its full potential.`

 

Has the NEC changed on this?

In 2001 the utility trenched my yard and put in the 4/0 AL electric service plus phone and cable TV feeds, a 12/3 UF cable going the other direction for 120V yard outlets, and an innerduct for future use.

This was all done under permit and the electrical inspector OK'd it, although here they do not regulate low voltage.

 

socal, is cat 6 a data transfer cable for computers? In this case, would you string it to the garage to transfer data from the computer in my house, to the computer in the garage? I'm not a computer guy, so this question might seem uninformed.

And the two cables, are those cables for cable internet/television? And why two? Not that it's overkill, but I'm just not sure what all these cables are for. You've sparked my curiosity a bit, and I might end up running all sorts of neat stuff to the garage that I never dreamed of ! ! I've already got the trench dug, why not put it to good use, heh?!?

 

> Has the NEC changed on this?
> In 2001 the utility trenched my yard and put in the 4/0 AL
> electric service plus phone and cable TV feeds, a 12/3 UF
> cable going the other direction for 120V yard outlets, and
> an innerduct for future use.

I don't know of any change. Others and myself gave similar examples. My telephone and electric service share the same trench.

I do believe that gas lines and sewer lines require both a vertical and horizontal offset, perhaps 6" vertical and 18" horizontal.
I've not see that in the NEC. I have seen the shelf diagrams somewhere else, though, perhaps a consolidated code requirements.

The only other suggestion I have is strands of red flagging tape or the caution tape that says "BURIED ELECTRIC"... again after 4-8" fill is added to the ditch.

 

The 12" seperation for low voltage communication lines is a recommendation to reduce interference in the lines. They can be in the same trench, just not in the same conduit; you may experience some interference, but I'd take my chances and run the LV stuff.

CAT5e or CAT6 is a twisted pair (4 pair) communication cable that can be used for a computer network, intercom, telephone, security system, audio, etc. CAT6 has higher data transfer capabilities but can be troublesome for amateurs to terminate properly; CAT5e is adequate for home use and will be cheaper. I usually pull twice as many runs as I expect to use; it is quite versatile and also very resistant to interference.

Possible uses for coax lines are digital cable, satellite TV, video surveilance, computer cable modem. If you pull coax cable don't go with a lower rating than RG-6. The cheaper stuff is practically obsolete as it is only good for standard analog cable TV (not digital cable).

 

Just a few more points regarding low-voltage: Underground-rated cable (Cat 5, Cat 5e, Cat 6, RG-6, Doorbell wiring) is available but considerably more expensive and less available than indoor-rated stuff.

Unless I were running a moneymaking website or E911 PSAP in my garage, I would just put indoor low-voltage wiring in the underground conduit and take my chances. It would probably get wet and degrade over time, even in conduit, and then I would replace it.

I have a few of these underground runs and I blow out each underground conduit in the spring and fall with a shopvac. It's not worth renting a high-CFM trailer-mounted compressor, which is the recommended method. I am not sure if my approach works but I figure doing something is better than nothing.

 

You may also consider running wire for a three way switch for the exterior garage lights. That way if you hear some suspicious in the middle of the night you can light the area up.

 

Running speaker wire and coax cable(for TV and computer) together in conduit, underground to the garage, would that create some kind of electrical conflict? Noise or distorsion or something like that?
Or, am I safe in doing so? Thanks!

 

> would that create some kind of electrical conflict?
No.

> Noise or distortion or something like that?
Yes.

That's why at least 12" of separation is recommended.

Plus you should be snaking the cables anyway.

Long parallel runs have greater inductive coupling.
Random snaking helps to counter that.

 

recommended.(exactly that)

With ALL these stringent qualifications.... How do you compete?
Are you the only game in town? Are there no SAFE alternitives? Coz sometimes all you need is an inspection.....
Please enlighten me. (off topic, AGAIN)

Place in conduit, and bury it in the same trench. it will be fine.
Unless you want to open a night club (in wich case ,most won't notice anyway). Don't put them in the same conduit.

Or you could dig a bigger trench.

 

bolide,
>Long parallel runs have greater inductive coupling.
Random snaking helps to counter that.<

Inductive coupling, what's that?

Snaking, what's that?

Ignorance is bliss, and I'm pretty blissful.

 

Snaking is when you run a cable somewhat "wavy" through the trench instead of perfectly straight. Because of some complicated physics, cables which are straight and parallel with each other tend to cause more interference than cables which are snaked. One of the types of interference is inductive coupling where the magnetic field created by the power cable cable causes electricity to flow in the other parallel communication cable which disrupts the signal.

 

[QUOTE=Unless I were running a moneymaking website or E911 PSAP in my garage, I would just put indoor low-voltage wiring in the underground conduit and take my chances. It would probably get wet and degrade over time, even in conduit, and then I would replace it. [/QUOTE]

How long do you think regular cable would last? Are we talking 1, 2 or 20 years?

I'm considering the same except I will be running Cat 5e and RG6.

 

Lay in a 3/4 inch PVC conduit and pull the cat5 and quad-shielded RG6. You won't have any problem.

 

Well, I've had CMR rated Category 5 in a buried innerduct, which is just continuous polyethylene as opposed to sections of PVC, since September 2001 and I can still connect at 100 Mbps over about 60 feet.

RG-6 I don't have the experience with but a halfway measure might be to get the aerial stuff (with the messenger [support] wire) molded directly on the jacket. I've seen it at Home Depot. That would at least be outdoor rated. Just remember to use a hacksaw on the messenger wire because it's typically hardened. I am not sure if CATV companies even use a gel cable for underground drops.

 

#1, if sanctity is that important get divorced. (It's worth the money). Secondly, don't run anything smaller than 1", And run several, You never know. 3rdly, A new place would be nice then you don't have to live in a garage.
Just a thought- Perhaps a bad one.

 

At the risk of threadjacking, in the yard of the home we're buying, the owner has a black plastic corrugated drain pipe (flexible) hooked up to the sump pump output, and it is just laying on the grass going out about 50 feet. It ends just past the shed and shoots water into a little ditch-like depression that runs between the lots on our street.

I'd like to bury that pipe so it's not visible (have it come back up to grade past the shed), and also run electric out to the shed at the same time. I'll have a qualified electrician do the hookups, but my questions are:

a. Is it okay to run a conduit for the electric cable in the same trench as the pipe or should I run two parallel trenches, and

b. What kind of outdoor cable should I run for typical shed-like activity? I'd expect to run maybe an air compressor, shop-vac, table saw, chop saw, lights, and maybe a fan. Not all at the same time, of course. Plenty of room in the 200 amp breaker panel for dedicated circuits. Think 2 is enough?

c. Who do I tell that I'm doing this, so they know there is buried electrical in the yard 20 years from now? Buried rags or caution tape seems a bit .. half-assed, if you take my meaning. If this requires a permit, does the building department keep a record for posterity?

Thanks!

 

This is straying OT a lot but if you bury it you should trench enough so the pipe is supported on all sides by rock or compacted earth. That is, if it's not deep enough it can be collapsed by someone driving over it or whatever. I'd guess a foot, but check around. Mine is 2-4 feet below grade for other reasons.

Also I wonder what you mean by "have it come back up to grade." Does that mean poke out the side of a hill, or make a 90-degree turn to vertical? Gravity applies to water, so I am confused how this would work.


a. Same trench OK per previous opinions on this thread. In fact the electric will make a nice tracer if you ever need to have this pipe located in the future.

b. Look up "multiwire garage" for some references but I think if you run more than one multiwire (2 hots, 1 neutral) you need a subpanel. If you're just running two 20A circuits you can use 12/3 UF if local code allows, but it must be buried something like 24" deep unless it is protected by GFCI before it's buried.

Air compressors run the gamut. You should calculate your load and put in more than you expect. So for example maybe you want to put in 10/3 UF which could give you a 30A subpanel. That's out of my league, though.

c. A permit would most likely be required but the inspector will only check to see if code requirements are met. Your municipality will probably keep a record that the work was done for all time, so maybe you could file an as-built plot at the time of final inspection, and also put the original in with the stuff that you would pass on to a future owner.

But you would also be advised to put a permanent sign in the garage and by the panel in the house that says something like "Locate all private & public underground utilities before digging on property." Public locator services will not locate private utilities so you or future homeowners would have to hire a private locator.

Nothing half-assed about putting in caution tape. I bought a roll of danger tape and laid it in about 6-12 inches below the current surface, which is 1-3 feet above my pipe & wire. Hopefully future backhoes and shovels will find that in the first couple of bites. You can also buy metalized tape that can be located after burial.

 

I'll just comment on one of your questions.

You cannot run two (or more) circuits to a detached building...you can only run one circuit. You *can* however, run a single "multi-wire" circuit, which would provide the same power as two normal circuits. If you need more power than that, you will need to put a sub-panel out there...that would complicate things a bit though.

No matter what you do. consider running an oversized conduit out there rather than outdoor (UF) cable. This will allow you to upgrade later without digging a trench again.

For now, you would pull four #12 THWN wires (black-red-white-green) through it, giving you a 20A multi-wire (shared neutral) circuit. Connect black and red to a double pole 20A breaker in the main panel (technically, you can use two single pole 20A breakers, but its easy for things to go VERY wrong if you do). At the shed, bring these wires into a junction box, and split this multi-wire into two circuits...black to one circuits black, red to other circuits black, white to both circuits whites, green to both circuits ground wire (green or bare).

Later, if you need more circuits, remove the four #12's and pull four larger guage "feeder" wires in to go to a sub panel (which would replace the junction box). Then you can add additional circuits. The 20A double pole breaker used above would be replaced with a double pole breaker sized to your needs. You would also need to add a ground rod or two at the shed if you do the subpanel.

Don't forget GFCI protection...