Wire in trench

[mrcaptainbob]

I'm running two 1" PEX lines inside of a 7" insulator tube slipped inside a waterproof sleeve in a 46" deep trench for a total distance of about 95'from the house to am outside wood furnace. Along with this, I have a need of getting electrical (110)out to the unit the PEX is connected to. I would like to run a 220 line in that same direction and tap off one of the lines for the unit and use the other for a different 110 line. Would it be okay to lay that wire (it is direct burial) in the same trench? Or should I cover the water line with a layer of sand/dirt and then the wire? I do plan on laying a yellow 'caution' tape on top of it all for the 'future'.

[LazyPup]

I am not aware of any restrictions in the plumbing code concerning laying water and electrical services in a common trench. however their may be something in the National Electrical Code.

No doubt Hayzee can fill us in on this one. I do know that in some instances direct burial electrical is required to be encassd in concrete that has been dyed red, but I am not certain of the specifics. I think it is determined by the voltage.

Even if a review of the National Electrical Code does permit it, i would be inclined to lay it in the manner of laying water and sewer in a common trench, The trench must be dug in such a manner as to make a shelf on one side to keep the water at least 12 inches above and 12 inches to the side of the sewer line.

In this case, if it is permissiable to lay them both in the same trench i would want to keep the electrical above and to the side of the water line.

[Rewired]

I really like the idea of having the yellow caution tape in the trench! But, just a thought it may not be a bad idea to put that direct burial wire in some "duct" or something, not so much for the added protection, but if for some reason tomething happens to the wire, or should you want to change it in the future, it will be a hell of a lot easier to do... As for putting it in the same trench, I have seen gas, water and electrical in the same trench even, BUT it was a "sub service" out to a pool shed and probably wasnt even inspected (all is well with it still that was done some 20 years ago.. Too bad they didn't put the direct burial cable in a duct, its now a bit small for what we want to run in the shed , and we can't change it without lifting the patio

[mrcaptainbob]

You know, Rewired, I'd REALLY like to run it through a duct as you mentioned, but was always led to believe that wire with the outside case/shield is not permitted inside a duct work run. No place for heat to escape. Maybe what I should do is run separate wire through a duct. That would save possible future hassles, be cheaper, and probably more safe, as well. Hmmmmm.....may have to change my thinking on this...

[HayZee518]

Jeez! Ol Hazy to the rescue! Water, drain, power can all be run in the same trench. UF cable is direct burial and doesn't need to be enclosed in conduit. Only place conduit would be necessary is where the cable goes into the ground and exits. Telephone needs to be direct burial as well as computer communications cable. CAT 5E wth a weather resistant outer jacket must be used. While you're at it install a #8 stranded bare copper conductor for a good equipment ground. Those telephone guys don't care what they hitch their ground to, as long as it looks good! (I'm gonna get reamed for this!)

[mrcaptainbob]

HayZee, you're too good to me! Thanks for the quick response. Shall I run that #8 bare ground in addition to the ground that came with the direct burial? Sure don't mind doing that if it's a good idea. Even if it's a belt-and-suspenders approach, that's fine with me. And, would that #8 tie from the main house panel and be a one piece all the way through the ground to my outside 'extension' panel? That's what I plan to do with the #6/3 UF w/g.

[HayZee518]

Thing is about the grounds - they all have to terminate or originate at the panel to eliminate multiple ground paths. I suppose you could drive a ground rod at the remote location and use it but if there is a problem with soil resistivity between your panel, water pipe and the driven ground, it would prove to be a hazardous situation. Yes run the 8 along with the rest of what you're hiding in that trench. UF can go a minimum of 14 inches buried, in sand below and above the cable [no rocks] PVC, Rigid, 8 inches encased in concrete. Ground rod to ground cable shouldn't exceed 20 ohms in resistance - if a fuse were to be put in there, a 6 amp fuse should not blow! E[volts]=I[amps] X R[resistance] E divided by I equals resistance[R] 120/6=20 ohms

[mrcaptainbob]

Okay, HayZee, I'll pick up the bare stranded #8 tomorrow and run it along with the direct burial. Thanks for your help.

[mrcaptainbob]

Hm..they don't sell #8 stranded at the box stores!! I can get 4 or 6.The one guy at Lowes says it would be better to use a ground rod at the second location instead. Since the main panel is already grounded, And I'm running the 6/3 W/G, would that not effectually ground the second box? Now, I can see the additional bare #8 tying the two boxes together, but I don't like the idea of the second ground rof at that second box. For no other reason than that I always read/hear about two grounds off the same supply should not be done. So...shall I continue to get the #8?....forego any additional ground?....or go to #6 if I can't find the #8. Again, there's about 160' between the main panel and this sub. (it does have it's own shut off).

[HayZee518]

ok, get the no 6 ground and run that. I'm sorry that they can't supply the #8. It's very common. Use the proper terminations - compression fitings for the end of run (rin g tongue, spade tongue or whatever.) Add some no-alox and your resistance problems should be over. Ground everything to the #6 ring back to the panelbox. I'm sure the inspector will say this is overkill, but in the long run, he'll say it is approved and in compliance with the code. Trust me!

[mrcaptainbob]

Okay, that's what I figured. Why would spade or any kind of connector be better than just slipping it under one of the bus screws? And what is alox?

[LazyPup]

I am aware of a regulation in the NEC which states that if you cannot get 25ohms or less to ground that you must add additional grounds, but i never heard of a reg. that would prevent you from adding additional grounds.

Nolox is a liquid paste anti oxidant compound that is put on the wire in fittings to prevent oxidation or corrosion on the wire. It is available at any electrical supply or in the electrical dept of the big box stores.

Hayzee is absolutely correct about overkill, but in most cases when inspectors check DIY projects they are extremely critical and you never get a second chance to make a first impression..obvious overkill will go a long way in establishin your repore with the inspector.

[mrcaptainbob]

Thanks for the info on the anti oxy. Will follow through with that. And I agree with the 'first impression' viewpoint.