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Equipment Discussions >> Observatories

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Raginar
Post Laureate
*****

Reged: 10/19/10

Loc: Rapid CIty, SD
Poll: Electrical service?
      #5985169 - 07/22/13 09:33 PM

Hey guys,

So I'm getting more and more automated... but, I don't have 'real' electrical service to my shed. I run an extension cord and my ethernet cord out to it every day I use it (usually leaving it out there if the weather is good). Not the best situation obviously.

So, I'm thinking about getting electrical service to the shed. The run would be roughly 75' tops to the shed. How much did it cost you to get power out to your shed? What are the different options ya'll have done besides that? Anyone else just running an extension cord?

Thanks guys,

Chris


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tadpoletoo
super member
*****

Reged: 04/18/11

Loc: NW Michigan
Re: Poll: Electrical service? new [Re: Raginar]
      #5985625 - 07/23/13 08:29 AM

Hi Chris, One 20 amp circuit #12 direct burial, the grey wire, to a ground fault receptacle would be capable of providing at least as much power as your extension cord. Burying the stuff is where the fun starts. You laughed at my four legged chicken a while back.

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jazle
super member


Reged: 05/20/10

Loc: California, USA
Re: Poll: Electrical service? new [Re: tadpoletoo]
      #5986534 - 07/23/13 05:56 PM

Having done it both ways now, having permanent electrical is nice if you plan to run other things off the sub-panel in the future, but for just an observatory, I think the extension cord is a better option -- assuming the you can live with the cord running across the yard.

You can replace your extension cord with 10-gauge SOOW cable. This is the industrial-quality stuff and you can get it a spool of it at home depot. It's designed to handle the elements and abuse. Plug it into a GFCI outlet at the house, put a couple of inches of mulch over it to hide it, and you're set. Cost for a spool of wire will set you back about $150 to $250 depending on length.

The single 20-amp circuit, direct burial, GFCI-protected option would be a close second. Can be "shallow" burial (12" I believe) versus the typical 18". Cost will be a little cheaper than the SOOW cable, but you have to trench or dig by hand. A trencher can be rented at home depot for about $150. Worth every penny for 75 feet. Give yourself two hours to trench and two hours to clean it :P

The 240V, conduit, 18" burial, heavy gauge, permanent connection is how I went with my latest observatory. About 80' run through a crawl space and then about 70' underground. 170' of #3/#3/#3/#8 TWWN cable set me back $500. About $200 in PVC conduit and fittings. $100 for the sub-panel and breakers. $150 for the trencher rental. So, just under a grand. I got an electrician to quote the job as well and they wanted $1700 and they would have used smaller aluminum wire.


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Raginar
Post Laureate
*****

Reged: 10/19/10

Loc: Rapid CIty, SD
Re: Poll: Electrical service? new [Re: jazle]
      #5986724 - 07/23/13 08:23 PM

Jason,

You did the 240V yourself? SD is actually a fairly lenient state when it comes to electrical code. I'm allowed to do it myself and have it inspected by an electrical inspector. The biggest problem I have is knowing how the connection into the electrical box will go. I feel confident I could wire it up from the shed to the panel; I don't feel confident at that point .

Thanks for a great review of what you've done. That's exactly what I was hoping for.

Tad, I'm hoping for a more permanent solution that gets me away from using an extension cord.

Chris


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Bigstar
member


Reged: 03/08/11

Loc: Naperville, IL
Re: Poll: Electrical service? new [Re: jazle]
      #5986730 - 07/23/13 08:27 PM

Watch what your codes are in the area. In my area burying soow cord is a no no. And the 12" sounds too shallow to be up to code.. Hire a electrican have him install a sub panel in your observatory. Do it once and do it right. I now alot of people like to do diy jobs. But they don't understand the difference between grounding and bonding. Better to be safe.

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Raginar
Post Laureate
*****

Reged: 10/19/10

Loc: Rapid CIty, SD
Re: Poll: Electrical service? new [Re: Bigstar]
      #5986746 - 07/23/13 08:41 PM

Bigstar,

Yea, this is one of those projects that makes me a tad nervous. The 'GFCI outlet' to my shed doesn't quite fly .

Chris


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Bigstar
member


Reged: 03/08/11

Loc: Naperville, IL
Re: Poll: Electrical service? new [Re: Raginar]
      #5986772 - 07/23/13 08:54 PM

The hardest part is done. You got an observatory. Call a couple 3 electicans. Let them quote it out. Quotes are free.

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David PavlichAdministrator
Transmographied
*****

Reged: 05/18/05

Loc: Mandeville, LA USA
Re: Poll: Electrical service? new [Re: Bigstar]
      #5986911 - 07/23/13 09:55 PM

I have a 20 amp circuit buried, however, I was lucky. The couple that owned the home before us had an above ground pool, so the line was already buried! All I had to do was remove about 15' of the line since where it was stubbed up wasn't close to the obs' location. I just stubbed up fresh conduit into the obs.

David


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Phil Sherman
Pooh-Bah


Reged: 12/07/10

Loc: Cleveland, Ohio
Re: Poll: Electrical service? new [Re: jazle]
      #5987126 - 07/23/13 11:43 PM

Quote:


The 240V, conduit, 18" burial, heavy gauge, permanent connection is how I went with my latest observatory. About 80' run through a crawl space and then about 70' underground. 170' of #3/#3/#3/#8 TWWN cable set me back $500. About $200 in PVC conduit and fittings. $100 for the sub-panel and breakers. $150 for the trencher rental. So, just under a grand. I got an electrician to quote the job as well and they wanted $1700 and they would have used smaller aluminum wire.




I'm surprised your electrical code let you do that. Where I live, a 240V circuit to an outbuilding requires a complete separate earth ground. This means multiple 8' ground rods, preferably driven vertically into the ground, connected using welded electrical connectors. I do all of my own house wiring (with a 100% pass rate on inspections) and decided that that wasn't a job for me and went with a 110 circuit to the garage which didn't require the grounding system.

Phil


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rimcrazy
sage


Reged: 03/03/12

Loc: Overgaard, AZ
Re: Poll: Electrical service? new [Re: Phil Sherman]
      #5987588 - 07/24/13 09:49 AM

I had a certified electrician run a 50Amp service to my observatory. The distance was about 75'. Code in Navajo County is that a subpanel is grounded at the source NOT at the subpanel. That is to say, at the subpanel there is no connection between ground and neutral. This prevents ground loops. I wired the inside of the observatory, which in my case, was fairly simple. I ran the larger service (it could actually supply 60Amp if I changed the main breaker) as the difference in price was small and I figured it's cheaper to overestimate now rather than run short in the long run. It cost just about $600 if I remember correctly. The ditch and conduit was already in for 2/3rd's the distance. The other part ran under my deck on my house, which the electrician supplied. In my case, he did a first class job.

Now what needs to be seen is the lighting protection I'm having put in. That is impressive. My property is quite high on the top of a hill and we get a lot of lighting especially now during monsoon season here in Az.


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Happy Birthday Achernar
Postmaster
*****

Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: Poll: Electrical service? new [Re: Bigstar]
      #5987809 - 07/24/13 12:49 PM

12-inches is too shallow for any electrical code I heard of for direct burial, but not in rigid steel conduit, especially if encased in concrete where vehicles will not be driving over it. What I would have done is to dig a trench at least 18-inches deep, and use cable approved for direct burial with the metal warning tape above it. This cable has a really tough outer jacket rated for wet locations along with the insulation on the individual conductors inside. Alternatively, use of the appropriate sized PVC conduit then pulling THHN insulated conductors through it is a good bet, because THHN insulation is rated for a wet location. Underground conduit is always considered to be a wet location. Bonding and ground is extremely important, the difference between the two is simple. Bonding is ensuring there is no electrical potential between different conduits, panels or any other component of an electrical system. That is why bonding jumpers and straps are used. I bond light fixtures, panels and motors to their foundations aboard ship, which also grounds them because the hull is the ground plane also. Grounding is providing a low impedance path to the Earth for any fault current that results from ungrounded wires touching the frame or casing of a load, junction box, conduit or panel enclosure. In other words, if a fault occurrs, the current has an easier path to go to ground other than through your body if you touch the equipment and the outer shell has become energized. The massive flow of current to ground will then trip the breaker or blow a fuse. That is what anyone who is doing electrical work either as a DIY'er or an electrician must understand to do the job right and safely. Bigstar's right, SOOW cord is not meant for dirct burial, it is intended to hardwire machines to a building's wiring or as heavy duty electrical cords. I use this for my welding machine in fact.

Taras


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tadpoletoo
super member
*****

Reged: 04/18/11

Loc: NW Michigan
Re: Poll: Electrical service? new [Re: Achernar]
      #5988425 - 07/24/13 08:29 PM

Raginar, An old saying from Michigan, ground is ground the world around! Now that it is getting into tomato canning season another is, a pints a pound the world around.And thats all for tonight .

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Raginar
Post Laureate
*****

Reged: 10/19/10

Loc: Rapid CIty, SD
Re: Poll: Electrical service? new [Re: tadpoletoo]
      #5988538 - 07/24/13 09:40 PM

Tad,

LOL. Nice . Taras, that's interesting. I've heard the direct burial cables allow you to go to 12". If you run individual wires in conduit you have to go to 18".

Could be different NEC provisions in different necks of the woods.

Definitely wouldn't use SOOW. I contacted an electrician to come give me a quote, I'll keep you posted.

Chris


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Happy Birthday Achernar
Postmaster
*****

Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: Poll: Electrical service? new [Re: Raginar]
      #5988639 - 07/24/13 10:35 PM

When I buried direct burial cable on the job, I buried it four feet underground. Then I placed the red metallic warning tape above it to prevent people from getting electrocuted if they dig in the area. Electrical codes are the bare minimum, I would bury such a cable deep enough to ensure someone does not find it the way I once found a Romext cable, the hard way buried in the ground and it was live. I didn't appreciate being hit with 240-volts either.

Taras


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eastwd
member


Reged: 08/21/11

Loc: Nashville
Re: Poll: Electrical service? new [Re: rimcrazy]
      #5988701 - 07/24/13 11:17 PM

rimcrazy, anything you're willing to share about your lightning protection install would be very welcome by me, either here or in a separate thread. Thanks.

Quote:

Now what needs to be seen is the lighting protection I'm having put in. That is impressive. My property is quite high on the top of a hill and we get a lot of lighting especially now during monsoon season here in Az.




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jazle
super member


Reged: 05/20/10

Loc: California, USA
Re: Poll: Electrical service? new [Re: Phil Sherman]
      #5988918 - 07/25/13 02:15 AM

Quote:

Quote:


The 240V, conduit, 18" burial, heavy gauge, permanent connection is how I went with my latest observatory. About 80' run through a crawl space and then about 70' underground. 170' of #3/#3/#3/#8 TWWN cable set me back $500. About $200 in PVC conduit and fittings. $100 for the sub-panel and breakers. $150 for the trencher rental. So, just under a grand. I got an electrician to quote the job as well and they wanted $1700 and they would have used smaller aluminum wire.




I'm surprised your electrical code let you do that. Where I live, a 240V circuit to an outbuilding requires a complete separate earth ground. This means multiple 8' ground rods, preferably driven vertically into the ground, connected using welded electrical connectors. I do all of my own house wiring (with a 100% pass rate on inspections) and decided that that wasn't a job for me and went with a 110 circuit to the garage which didn't require the grounding system.

Phil



You are correct.

Because of the distance, you can't get by with just the ground wire. You have to have ground rods as well -- I have two 8 foot rods tied into the neutral bus of the sub as well as the connection to the main house on the #8. NEC 250.32(A), NEC 250.50, and NEC 250.53(A)(2).


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jazle
super member


Reged: 05/20/10

Loc: California, USA
Re: Poll: Electrical service? new [Re: Bigstar]
      #5988920 - 07/25/13 02:20 AM

Quote:

Watch what your codes are in the area. In my area burying soow cord is a no no. And the 12" sounds too shallow to be up to code.. Hire a electrican have him install a sub panel in your observatory. Do it once and do it right. I now alot of people like to do diy jobs. But they don't understand the difference between grounding and bonding. Better to be safe.



NEC 300.5:
Table 300.5 Minimum Cover Requirements, 0 to 600 Volts, Nominal, Burial in Millimeters (Inches)
Residential Branch Circuits Rated 120 Volts or Less with GFCI Protection and Maximum Overcurrent Protection of 20 Amperes
All locations not specified below: 12"
In trench below 50-mm (2-in.) thick concrete or equivalent: 6"
Under minimum of 102-mm (4-in.) thick concrete exterior slab with no vehicular traffic and the slab extending not less than 152 mm (6 in.) beyond the underground installation: 6" direct burial, 4" in raceway (conduit)
Under streets, highways, roads, alleys, driveways, and parking lots: 24"
One- and two-family dwelling driveways and outdoor parking areas, and used only for dwelling-related purposes: 12"
In or under airport runways, including adjacent areas where trespassing prohibited: 18"
And under "Notes":
5. Where solid rock prevents compliance with the cover depths specified in this table, the wiring shall be installed in metal or nonmetallic raceway permitted for direct burial. The raceways shall be covered by a minimum of 50 mm (2 in.) of concrete extending down to rock.


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jazle
super member


Reged: 05/20/10

Loc: California, USA
Re: Poll: Electrical service? new [Re: Raginar]
      #5988924 - 07/25/13 02:30 AM

Quote:

Jason,

You did the 240V yourself? SD is actually a fairly lenient state when it comes to electrical code. I'm allowed to do it myself and have it inspected by an electrical inspector. The biggest problem I have is knowing how the connection into the electrical box will go. I feel confident I could wire it up from the shed to the panel; I don't feel confident at that point .

Thanks for a great review of what you've done. That's exactly what I was hoping for.

Tad, I'm hoping for a more permanent solution that gets me away from using an extension cord.

Chris



Electrical work runs in my family. My uncle owned his own electrical contracting company. So, I've been around. And I've done lots of research of the codes.
In my county, you can do all of your own personal electrical work -- it'll be inspected just like any other contractor.
Although, out here, even the inspectors don't know all of the codes I showed them my grounding rod connections and asked if it was OK to run the bonding wires connecting the two rods underneath the raised observatory on the ground or should I bury them. The inspector first asked, "Why do you need them?" After explaining that the code required it, he said it would be fine to leave them on the surface.

They generally have a couple inspectors who inspect a large area every day. They know bits and pieces of the code for electrical, structural, plumbing, etc... Generally, if what they know to look for looks good, then they assume you know what you are doing and approve the work.

In fact, when I had the inspector out for my rough electrical inspection, I asked him when I should have him out next. He said that because it wasn't a residential building and everything looked great so far to just call him out again for the final inspection.


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jazle
super member


Reged: 05/20/10

Loc: California, USA
Re: Poll: Electrical service? new [Re: rimcrazy]
      #5988953 - 07/25/13 02:58 AM

Quote:

I had a certified electrician run a 50Amp service to my observatory. The distance was about 75'. Code in Navajo County is that a subpanel is grounded at the source NOT at the subpanel. That is to say, at the subpanel there is no connection between ground and neutral. This prevents ground loops. I wired the inside of the observatory, which in my case, was fairly simple. I ran the larger service (it could actually supply 60Amp if I changed the main breaker) as the difference in price was small and I figured it's cheaper to overestimate now rather than run short in the long run. It cost just about $600 if I remember correctly. The ditch and conduit was already in for 2/3rd's the distance. The other part ran under my deck on my house, which the electrician supplied. In my case, he did a first class job.




You are correct that the neutral and ground is only tied at the main service entrance and all subpanels must have separate neutral and ground bus bars. Not so much for ground loops as much as you don't want the ground wire to become current carrying should the neutral fail.
But should your building be sufficient distance (just about any detached building), then you'll need a grounding electrode at the secondary building.

NEC 250.32 Grounding and Bonding
Grounding and Bonding Buildings supplied by a branch circuit or feeder shall have an equipment grounding conductor run with the supply conductors and connected to the grounding electrode system at the separate building.

This is the latest (2011) NEC cycle.


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roscoe
curmudgeon
*****

Reged: 02/04/09

Loc: NW Mass, inches from VT
Re: Poll: Electrical service? new [Re: jazle]
      #5989060 - 07/25/13 07:04 AM

I'm too far from the house with mine.......I power it with an old car battery. One of these days, I'll put a solar charger on it, but it lasts for weeks between charges, I carry it up to the garage now and then for that....
R


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