I have a really off the wall question about trenching an underground wire

[snymat68]

Don't forget to check minimum burial depths for your area. I know around here it's a minimum of 18" deep for 120V stuff in PVC conduit. I'm not sure if that holds true for low voltage and/or data wiring, or if it's different in your area. Just something to keep in mind. Makes sense though, so as not to hit it with a rototiller or something in the future.

 

[Industrial Toys]

A hundred feet of CAT 6 direct buried could make a nice lightning target.

 

[snymat68]

A hundred feet of CAT 6 direct buried could make a nice lightning target.

How do you figure?

 

[Industrial Toys]

Because lightning has only one purpose. To disipate into the ground, and a given amount of ground only sucks up so much lightning. So when there is a nice highly conductive wire in the ground, the lightning makes a B-Line toward it and blows part anything on the ends. Much more susceptible than overhead plant.

Just for starters, I would put the cable in pipe, making everything that much more difficult. But, better physical and lightning protection and the option if ever needed of pulling in a new cable.

listen to me, and your life will get much more complicated, quickly.

 

[farmeratheart]

you could rent a sod cutter, and use that to take up the grass in the path that you want, then when finished, just lay the sod back down, and you won't notice it was ever cut.. this is the most unobtrusive method to get the sod back quickly..

A couple of years ago I ran electrical service to my tractor shed. My electrician offered to make the 150’ trench with his ditch witch. I agreed, but after I had used a 4” wide flat spade to remove the sod in approximately 8 or 10 inch “strips” the entire length. After he dug the trench, placed conduit, wire, etc and had it inspected the trench was backfilled with the dirt. I then put the sod strips back down and drove the tractor back and forth to compress. A little water to refresh the grass and within a couple of weeks it was as good as new!

 

[k0ua]

A hundred feet of CAT 6 direct buried will make a nice lightning target.

fixed if for you!

 

[k0ua]

How do you figure?

Any metallic conductor you put into the ground will have voltage rises when the earth currents flow to equalize the nearby lightning strikes.

Fiber optic cable would be a much better choice as it is made of glass and is therefore nonconductive.

Of course you can put good lightning protection on your metallic conductor to help guard against destruction of your devices.

Lightning is just as much a ground phenomenon as an aerial phenomenon. This is why cattle are killed from nearby lightning strikes. Not that the bolt from the blue struck the cow, but the earth currents flowing in the ground the cow is standing one raises voltages between the cows hooves. Since a cow has rather large distance's between its hooves those voltage rises produced from the flowing earth currents can have a rather large voltage gradient between them. This is also why if you must abandoned your automobile and step out into the ground from a downed high voltage wire laying on the ground, you should shuffle your feet and not let a lot of distance accrue between your feet. You don't want to wind up like the cow.

If you don't want lightning issues, or having to deal with lightning issues, don't put any metallic conductor in the ground.

 

[k0ua]

Of course putting in fiber optic cable increases the expense and complexity and the equipment (transceivers) on each end will also need surge protection for their AC power supplies. Of course you will likely already need that from the computer equipment on each end anyway.

 

[snymat68]

Any metallic conductor you put into the ground will have voltage rises when the earth currents flow to equalize the nearby lightning strikes.

Fiber optic cable would be a much better choice as it is made of glass and is therefore nonconductive.

Of course you can put good lightning protection on your metallic conductor to help guard against destruction of your devices.

Lightning is just as much a ground phenomenon as an aerial phenomenon. This is why cattle are killed from nearby lightning strikes. Not that the bolt from the blue struck the cow, but the earth currents flowing in the ground the cow is standing one raises voltages between the cows hooves. Since a cow has rather large distance's between its hooves those voltage rises produced from the flowing earth currents can have a rather large voltage gradient between them. This is also why if you must abandoned your automobile and step out into the ground from a downed high voltage wire laying on the ground, you should shuffle your feet and not let a lot of distance accrue between your feet. You don't want to wind up like the cow.

If you don't want lightning issues, or having to deal with lightning issues, don't put any metallic conductor in the ground.

I get what you're saying, but how does that explain the extensive ground systems we hams (and broadcast stations) put in for towers, etc.?

 

[k0ua]

I get what you're saying, but how does that explain the extensive ground systems we hams (and broadcast stations) put in for towers, etc.?

So that direct lighting strikes on those towers can equalize to ground without equalizing in other ancillary circuits. Like going thru the equipment to equalize. You cannot stop the direct strike, you can only supply a low impedance path for it to equalize. ground currents will still flow.