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Digging a trench from house to observatory site.

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#1 Tom Gwilym

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Posted 23 July 2014 - 12:17 AM

Thanks to those who answered my power vs. network distance question. It seems two conduits a few inches apart and at least 18 inches or more deep.

My next problem which is really getting me frustrated. I plan on running 65 feet from the house to the observatory. My house is build on a fill of gravel since the site was formerly a hole or not flat. About 6 inches below the lawn, I hit the very rocky base. Rocks with dirt between are between about 2 to 6 inches average, with an occasional big one of maybe 8 inches.
I called place today about a 24 inch ditch digging machine and described my situation. The guys said that the machine wouldn't do well with that kind of digging.
I did spend a long time digging a hole for the pier, it's about 2x2 feet and probably about 2.5 feet deep now. If I have to dig a 18+ inch trench 65 feet by hand, I don't know how I'll to it.
Anyone have any good ideas?

Not a very good photo, but you can see the maximum depth of the "soft" ground I dug out and the pier hole in the middle. You can see the pile of rock I dug out.

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#2 TCW

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Posted 23 July 2014 - 12:51 AM

You could hire (or rent) a mini excavator or some day laborers! Landscape contractors have mini sized equipment that fit through gates.

http://www.bobcat.co...tors/models/418

#3 planet earth

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Posted 23 July 2014 - 03:54 AM

Call more places is what I would do.
I give you credit for all the bull work you've done so far.
Rocky soil and a sore back is just no fun.
For manual digging a pick axe is very useful for stoney land.
Sam

#4 Startraffic

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Posted 23 July 2014 - 05:55 AM

Tom,
Time to rent a Ditchwitch, Backhoe, Terramite, SOMETHING that'll can move some dirt. Hand digging 65ft of 18in of trench, even a 4in wide (Minimum size you can get a away with) is still 32.5 cu ft of dirt. Lotta work, save your back, rent a machine. It can go through the small to medium sized rocks with no problem. You'll be done in a day & not crippled for a week. DAMHIKT

BTW, That tree is not a good pier. Too small & not centered.


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#5 Goodchild

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Posted 23 July 2014 - 06:30 AM

I don't see why the trench has to be 18 inches deep. Deep enough to remain hidden and still allow the grass to grow properly should be sufficient. A water line on the other hand should be deeper. And digging a "V" channel instead of a trench is much easier.
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#6 planet earth

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Posted 23 July 2014 - 07:23 AM

It's code when using pvc in my area.
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#7 tim57064

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Posted 23 July 2014 - 08:24 AM

Tom,Looks like one heck of a lot of work. I'm with others and suggest renting a small backhoe and digging it yourself. You can always take out a section of fence to get in and out.That is what I did to allow my stepson access with his loader and 12 inch auger attachment to get my footings dug. Hard clay kept me from digging them myself.Although,I did not have rocks like you have. A backhoe should take care of your problem though. Ditch Witch would just bounce around on rocks that size. What ever you decide,Good Luck.

#8 hbastro

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Posted 23 July 2014 - 10:28 AM

Good suggestion. I had help from a neighbor at a reasonable rate. He graded the road, dug footings, the trench for the data lines, and the trench for water pipes from the well...

He was kind enough to let me give it a try...
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#9 Tom Gwilym

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Posted 23 July 2014 - 10:47 AM

I don't see why the trench has to be 18 inches deep. Deep enough to remain hidden and still allow the grass to grow properly should be sufficient. A water line on the other hand should be deeper. And digging a "V" channel instead of a trench is much easier.


I'm just thinking of electrical codes that should be followed in this case. 18+ seems to be minimal to be "legal" and frustrating!

#10 Tom Gwilym

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Posted 23 July 2014 - 10:49 AM

You could hire (or rent) a mini excavator or some day laborers! Landscape contractors have mini sized equipment that fit through gates.

http://www.bobcat.co...tors/models/418

Hmm...that does look to be about the right size. Does a little shovel thingy like that dig up rocks easy enough? Better than a trench or "ditch witch" type machine?
I was hoping to have construction well underway by now, but I'm just kind of stuck right now with this. Maybe I'll have it built by September - and miss both of the clear Seattle skies for this season!

#11 dmcnally

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Posted 23 July 2014 - 11:00 AM

Have you thought about solar power and a wifi setup?

I like wired connections, but sometimes there are other ways.

I was wondering how many people do a "cost analysis" of wired (backhoe, trenches, conduit, cables) versus wireless (solar panels, inverter, batteries, directional antennas for wifi) before they make a final decision.

Just a thought and my $0.02.

Dave

#12 GJJim

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Posted 23 July 2014 - 12:25 PM

Have you thought about solar power and a wifi setup?

I like wired connections, but sometimes there are other ways.

I was wondering how many people do a "cost analysis" of wired (backhoe, trenches, conduit, cables) versus wireless (solar panels, inverter, batteries, directional antennas for wifi) before they make a final decision.


Heck no!, or only in hindsight. That's why we're called amateurs. :tonofbricks:

#13 Startraffic

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Posted 23 July 2014 - 12:43 PM

Tom,
Right up your alley.
http://rentalsunlimi...g/backhoes.html
I've used one of these for a septic line replacement. Worked a treat. It dug& filled a 14in wide trench 36" deep (code required)120ft long in a day. Only needs 4 ft wide to get in. The plumbing company gave me a $5000 estimate & a week to complete. I was done in a day.

As far as the trench depth, call your local permitting folx & talk them about what you're trying to do. That's what we get paid to do. Also it's a LOT easier to put it in right the 1st time & not have a upset code inspector make you redo it to code, and then have fine you for not doing it right to start with. DAMHIKT :o

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#14 TCW

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Posted 23 July 2014 - 02:10 PM

You could hire (or rent) a mini excavator or some day laborers! Landscape contractors have mini sized equipment that fit through gates.

http://www.bobcat.co...tors/models/418

Hmm...that does look to be about the right size. Does a little shovel thingy like that dig up rocks easy enough? Better than a trench or "ditch witch" type machine?
I was hoping to have construction well underway by now, but I'm just kind of stuck right now with this. Maybe I'll have it built by September - and miss both of the clear Seattle skies for this season!


A small machine like that has a lot of power. It won't dig through solid rock but it will dig most rocks unless you have 1000# boulders.

Ditch Witch machines don't work well with rocks of any size. If you do rent one, get one with rock teeth.

#15 Tom Gwilym

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Posted 23 July 2014 - 08:55 PM

Thanks for the tips. I found a guy that is stopping by tonight to give an estimate on what it costs with his excavator. Otherwise I could rent one for a day for about $450 with pickup/delivery. I'll see what this guy says. Hopefully less, then I'll have it done quick and by someone who knows how to operate the machine so I'm not learning by doing!

#16 roscoe

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Posted 23 July 2014 - 11:05 PM

Tom,
If possible, offer to be his helper - cleaning/smoothing the bottom of the ditch, gluing sections of pipe together, doing the initial backfill (putting a couple inches of mostly rock-free fill in over the conduit), raking dirt out of the grass, etc. If he never gets off the machine, it'll cost you a bunch less. Also, plastic conduit is cheap, consider putting a third run in, for whatever you may want it for next year.....

#17 Lord Beowulf

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Posted 23 July 2014 - 11:10 PM

If you could get a tractor in there to pull it, one of these does a pretty amazing job of ripping a trench for pipe. You can even get an attachment that will lay flexible pipe/hose in one shot, assuming the rock isn't too big/solid. Otherwise you just have to clear the trench by hand once it's ripped.

http://www.tractorsu...reg;-sub-soiler

Beo

#18 Christopher Erickson

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Posted 24 July 2014 - 03:16 PM

Another potential alternative exists.

If you were to install a male power "inlet" box on your observatory, you could run a 100' 12ga heavy-duty extension cord to your observatory and be code-compliant.

And if you were to slit your sod and stuff the extension cord just underneath the sod, that would also be code compliant, because the code doesn't say much of anything about the handling and routing of "temporary" extension cords.

I would plug the cord into a GFCI outlet on the house.

I am not saying that this is a great solution. The extension cord would be at risk from shovels, spades, spikes, lawn darts and anything else that might pierce your sod and puncture the cord underneath. However the GFCI outlet on the house would at least protect anyone from electrocution.

Proceed at your own risk.

#19 TCW

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Posted 24 July 2014 - 04:26 PM

Running a cord under the sod is really a bad idea. I would rank it with running a cord under the carpet. Running a cord is a temporary solution but permanent power is obviously the best.

#20 Christopher Erickson

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Posted 24 July 2014 - 09:35 PM

Running a cord under the sod is really a bad idea. I would rank it with running a cord under the carpet. Running a cord is a temporary solution but permanent power is obviously the best.


Like I said...

#21 Tom Gwilym

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Posted 24 July 2014 - 10:04 PM

Another potential alternative exists.

If you were to install a male power "inlet" box on your observatory, you could run a 100' 12ga heavy-duty extension cord to your observatory and be code-compliant.

And if you were to slit your sod and stuff the extension cord just underneath the sod, that would also be code compliant, because the code doesn't say much of anything about the handling and routing of "temporary" extension cords.

I would plug the cord into a GFCI outlet on the house.

I am not saying that this is a great solution. The extension cord would be at risk from shovels, spades, spikes, lawn darts and anything else that might pierce your sod and puncture the cord underneath. However the GFCI outlet on the house would at least protect anyone from electrocution.

Proceed at your own risk.


I do like that idea, but my GF isn't impressed with that. My last observatory was terrible, I had a 100 foot extension cord strung across the yard along with network cable. Yes, I planned on underground stuff, but never got around to it. For 10 of the 11 years I lived there, I ducked under network cable, and lifted the extension cord to mow under. Yeah...very ghetto!
I got an estimate last night from a guy who could come dig the trench (as well as any other yard digging we wanted) but he wanted $1,000 for the whole thing. Way too much. I hope to spend up to $2,000 for this at the most. My last observatory was just under $2,000 but that was about about 10 years ago.
It would be about $400-ish to rent an excavator for the day, then maybe another $100 for the u-haul to tow the thing home for the day. Ugh!
I feel I'm not getting anywhere with this! Maybe I'm foolish doing this again since I'm in the Seattle area and our clear nights have dwindled over the years. Is stamp collecting a satisfying hobby?

Here is my old observatory.

#22 TCW

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Posted 24 July 2014 - 10:08 PM

Direct burial cable is a code approved alternate that still would need to be buried 18".

#23 Tom Gwilym

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Posted 24 July 2014 - 10:21 PM

Direct burial cable is a code approved alternate that still would need to be buried 18".


Yep. 18" is my goal for depth - I just have to get through these rocks.

#24 JJK

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Posted 25 July 2014 - 02:35 AM

Running a cord under the sod is really a bad idea. I would rank it with running a cord under the carpet. Running a cord is a temporary solution but permanent power is obviously the best.



Running a cord under a carpet is potentially hazardous because it's a tripping hazard, and can cause fires (if the cord is undersized for the load).

While not ideal, Chris' suggestion doesn't present either of those two issues. In fact, the extension cord may have a longer lifetime because it's protected from solar ultraviolet light.

That said, I agree that a permanent power line is best.

#25 mattw

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Posted 25 July 2014 - 08:09 AM

I've used a trencher to do the job you are asking about.

Waaaay easier than using anything with a shovel on the end,

and they are actually fairly easy to handle. Any equipment rental place has them.

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