Building and Construction - Underground Wiring

Author

Underground Wiring

dgreen368

2007-02-09, 1:25 pm

Hello,
I just purchased a 6 acre country property in West Texas and am building a
small apartment (580SF). I didn't do a lot of research on supplying
electricity to the apartment and had the electric company place a meter on
the pole about 200 feet from the apartment. My intention was to trench and
bury the service wire. Now I browse through Home Depot looking at wire and
see some costing $5-6 per foot. Wow.
Can anybody tell me what size wire I require to run this service? My
intention was to in the future add another 1500 SF main home to this
structure. I thought I would power the entire thing from the box in the
apartment, but if the cost is out of sight I'll run service for the small
apartment and worry about power for the main house later when it's built (2
years).
I have another pole that's about 120 Feet from the structure so I could
possible eat the cost ($580) for the initial meter and have one brought
closer.
Does this make sense? Can anybody tell me what I'm looking at.

Thanks

Dave
Worried out West

hawgeye

2007-02-09, 8:25 pm

"dgreen368" wrote...
> I just purchased a 6 acre country property in West Texas and am building
> a
> small apartment (580SF). I didn't do a lot of research on supplying
> electricity to the apartment and had the electric company place a meter on
> the pole about 200 feet from the apartment. My intention was to trench and
> bury the service wire. Now I browse through Home Depot looking at wire
> and
> see some costing $5-6 per foot. Wow.

I hope this was a clue to stop now and start doing some proper planning
before you go any farther.

> Can anybody tell me what size wire I require to run this service?

Not until you decide the service amperage, the length of your run, and what
wire type is accepted by code.

> My intention was to in the future add another 1500 SF main home to this
> structure. I thought I would power the entire thing from the box in the
> apartment, but if the cost is out of sight I'll run service for the small
> apartment and worry about power for the main house later when it's built
> (2
> years).
> I have another pole that's about 120 Feet from the structure so I could
> possible eat the cost ($580) for the initial meter and have one brought
> closer.
> Does this make sense?

No

> Can anybody tell me what I'm looking at.

A mess! A potential catastrophe! A money-pit in the making.
Do yourself a huge favor and call an architect, an electrical engineer, the
utility company, or all of the above. They should be able to provide some
ideas that will save you money in the long run.

Steve Barker

2007-02-09, 8:25 pm

Once you figger out the power needs, keep in mind you can use smaller
(cheaper) wire if you go overhead. Also, it sounds like you were pricing
copper. Aluminum is perfectly acceptable in a service entrance application.

--
Steve Barker

"dgreen368" <u31625@uwe> wrote in message news:6d8e091a068a8@uwe...
> Hello,
> I just purchased a 6 acre country property in West Texas and am building
> a
> small apartment (580SF). I didn't do a lot of research on supplying
> electricity to the apartment and had the electric company place a meter on
> the pole about 200 feet from the apartment. My intention was to trench and
> bury the service wire. Now I browse through Home Depot looking at wire
> and
> see some costing $5-6 per foot. Wow.
> Can anybody tell me what size wire I require to run this service? My
> intention was to in the future add another 1500 SF main home to this
> structure. I thought I would power the entire thing from the box in the
> apartment, but if the cost is out of sight I'll run service for the small
> apartment and worry about power for the main house later when it's built
> (2
> years).
> I have another pole that's about 120 Feet from the structure so I could
> possible eat the cost ($580) for the initial meter and have one brought
> closer.
> Does this make sense? Can anybody tell me what I'm looking at.
>
> Thanks
>
> Dave
> Worried out West
>

Alan

2007-02-10, 1:25 pm

The above advice is understandable but probably exaggerated. Sounds
like you'll need at least a 200 amp main panel to service the small
apartment and main house together. You'll probably need no more than
a 100 amp subpanel for the apartment. Wiring underground is certainly
the more pleasing way to go in the long run, but you will need at
least 2" PVC conduit. It will be hard to pull wire through the full
200 feet even if it's a straight line, so I'd consider a splice box
part way. The wire that goes through the conduit should be three
separate braided cable type wires because the single 3 wire bundle
will be too difficult to pull. Aluminum is acceptable in a service
entrance application as said, but copper is certainly more durable,
and once installed you will be happy you used copper. If natural
gas is available, I'd bury a gas line in the trench as well (and a
water line too). Using natural gas or having a propane tank for home
and water heating and for cooking will reduce your amps needed
significantly, although A/C will still draw a lot too. You should
consult with an electrician though, and not just take advice from
here.

On Feb 9, 3:53 pm, "Steve Barker" <ichasetra...@some.yahoo.com> wrote:[color=darkred]
> Once you figger out the power needs, keep in mind you can use smaller
> (cheaper) wire if you go overhead. Also, it sounds like you were pricing
> copper. Aluminum is perfectly acceptable in a service entrance application.
>
> --
> Steve Barker
>
> "dgreen368" <u31625@uwe> wrote in messagenews:6d8e091a068a8@uwe...
>
>

Steve Barker

2007-02-10, 1:25 pm

ACTUALLY, aluminum is used for almost all service entrances. At least here
in the midwest. There's nothing more durable about copper, and once it's
installed, he'll not know the difference, so he'll not be happier or sadder
with either.

--
Steve Barker

"Alan" <atufft@gmail.com> wrote in message
news:1171126121.102530.111370@v33g2000cwv.googlegroups.com...
> The above advice is understandable but probably exaggerated. Sounds
> like you'll need at least a 200 amp main panel to service the small
> apartment and main house together. You'll probably need no more than
> a 100 amp subpanel for the apartment. Wiring underground is certainly
> the more pleasing way to go in the long run, but you will need at
> least 2" PVC conduit. It will be hard to pull wire through the full
> 200 feet even if it's a straight line, so I'd consider a splice box
> part way. The wire that goes through the conduit should be three
> separate braided cable type wires because the single 3 wire bundle
> will be too difficult to pull. Aluminum is acceptable in a service
> entrance application as said, but copper is certainly more durable,
> and once installed you will be happy you used copper. If natural
> gas is available, I'd bury a gas line in the trench as well (and a
> water line too). Using natural gas or having a propane tank for home
> and water heating and for cooking will reduce your amps needed
> significantly, although A/C will still draw a lot too. You should
> consult with an electrician though, and not just take advice from
> here.
>

HerHusband

2007-02-10, 1:25 pm

Dave,

> I just purchased a 6 acre country property in West Texas and am
> building a small apartment (580SF). I didn't do a lot of research on
> supplying electricity to the apartment and had the electric company
> place a meter on the pole about 200 feet from the apartment. My
> intention was to trench and bury the service wire. Now I browse
> through Home Depot looking at wire and see some costing $5-6 per
> foot. Wow. Can anybody tell me what size wire I require to run
> this service?

Generally, you need 4/0 aluminum cable or 3/0 copper cable for 200 amps.
Copper is really expensive right now, and Aluminum is typically used most
for underground services anyway. You just need to use an antioxidant
paste on the cable ends where it connects to your breaker panel.

However, different areas have different requirements, so check with the
agency that governs electrical permits in your area (You'll need a permit
to install a panel in the apartment anyway). They'll be able to tell you
what wire size and type you need.

Around here (Washington State), we typically use a cable designated for
underground service entrances. It's usually on a huge roll sitting on the
floor in the home centers (usually too large and heavy for their wire
racks). It consists of three individual 4/0 aluminum cables, one of which
has a stripe to indicate it is the neutral line.

I recently installed a new underground service at my in-laws house. I
used aluminum there too, except for the short feed between the meter on
the outside of their house and the panel on the inside. 3/0 copper was
much more flexible to feed through the conduit bends than the aluminum
cable would have been.

> My intention was to in the future add another 1500 SF main home to this
> structure. I thought I would power the entire thing from the box in
> the apartment, but if the cost is out of sight I'll run service for
> the small apartment and worry about power for the main house later
> when it's built (2 years).

We had the power company install a pedestal in the ground. Then we have
separate underground lines (and the associated service entrances) that
run to our garage, our house, and our pumphouse. The three buildings are
completely separate services, with only the electric meter in common (on
the pole out at the road).

We used this approach because the various buildings were constructed over
a period of many years and we didn't want to worry about trying to feed
one building off of another. It also allows us to have full 200amp
services at each building, and makes it easier to add new services in the
future. We had a mobile home on the property for a few years that tied
into the pedestal also.

I'd recommend you check with your electric company. They usually have an
engineering evaluation for the new entrance. They'll come to the site,
see what you have planned, tell you what requirements they have (separate
from the state electrical requirements), and charge you a few hundred
dollars.

It's all rather expensive, but you only do it once.

We had a couple of places on the property where we installed conduit
before we actually ran the cable. One was under a driveway heading to the
building site before we actually started building. We used 4" grey PVC,
with the appropriate bushings on each end to avoid cutting into the
cable. The conduit sat in the ground a couple of years before we actually
dug down again and ran the cable through it.

Anthony

bitternut

2007-02-11, 5:25 pm

"It will be hard to pull wire through the full
200 feet even if it's a straight line, so I'd consider a splice box"

I don't think Alan ever pulled any wire through conduit or he wouldn't have
made the above statement. I pulled 400 foot of 4/0-2/0 aluminum triplex
underground service cable through 3" pvc conduit by hand. It pulled pretty
easy even though I am not a big guy. If I had it to do over again I would
probably hook to a riding lawn mower and make it even easier. Two hundred
feet should be a piece of cake. Check with the power company and they will
tell you what you need. Most utility companies guarantee a certain voltage
at the meter so try and get the meter as close to the point of use as
possible. More volts are always better.

"dgreen368" <u31625@uwe> wrote in message news:6d8e091a068a8@uwe...
> Hello,
> I just purchased a 6 acre country property in West Texas and am building
> a
> small apartment (580SF). I didn't do a lot of research on supplying
> electricity to the apartment and had the electric company place a meter on
> the pole about 200 feet from the apartment. My intention was to trench and
> bury the service wire. Now I browse through Home Depot looking at wire
> and
> see some costing $5-6 per foot. Wow.
> Can anybody tell me what size wire I require to run this service? My
> intention was to in the future add another 1500 SF main home to this
> structure. I thought I would power the entire thing from the box in the
> apartment, but if the cost is out of sight I'll run service for the small
> apartment and worry about power for the main house later when it's built
> (2
> years).
> I have another pole that's about 120 Feet from the structure so I could
> possible eat the cost ($580) for the initial meter and have one brought
> closer.
> Does this make sense? Can anybody tell me what I'm looking at.
>
> Thanks
>
> Dave
> Worried out West
>

Glenn

2007-02-11, 5:25 pm

It's possible you are missing a easier/cheaper way.

Here, I put in the 2" pipe and also beside it 2, 1" pipes for
cable and phone. The meter is on the end of the house and P&L
supplied and pulled the wire from the pole to the house/meter.

"bitternut" <bitternut@adelphia.net> wrote in message
news:TuSdnS1vq5nJ61LYnZ2dnUVZ_o2vnZ2d@adelphia.com...
> "It will be hard to pull wire through the full
> 200 feet even if it's a straight line, so I'd consider a splice
> box"
>
> I don't think Alan ever pulled any wire through conduit or he
> wouldn't have made the above statement. I pulled 400 foot of
> 4/0-2/0 aluminum triplex underground service cable through 3"
> pvc conduit by hand. It pulled pretty easy even though I am not
> a big guy. If I had it to do over again I would probably hook to
> a riding lawn mower and make it even easier. Two hundred feet
> should be a piece of cake. Check with the power company and they
> will tell you what you need. Most utility companies guarantee a
> certain voltage at the meter so try and get the meter as close
> to the point of use as possible. More volts are always better.
>
>
> "dgreen368" <u31625@uwe> wrote in message
> news:6d8e091a068a8@uwe...

HerHusband

2007-02-12, 1:26 pm

> I pulled 400 foot of 4/0-2/0 aluminum triplex underground
> service cable through 3" pvc conduit by hand. It pulled
> pretty easy even though I am not a big guy.

I agree, it shouldn't be a big deal to pull cable through 200 feet of
conduit. We pulled three conductor 4/0 aluminum cable through 70 feet of
4" conduit that had two 45 degree bends. It went very easily. Assuming
you make a few preparations, it shouldn't matter if it's 200 or 500 feet.

1. Use larger conduit. It'll be a LOT easier to pull 4/0 cables through
3" or 4" conduit than it will through 2" conduit. This would also let you
upgrade to larger cable in the future if the need ever arose.

2. When you install the conduit, feed a "pull rope" through each section
so the rope is available at each end of the conduit.

3. If the conduit is already in, and you forgot to install a pull rope,
tie a piece of cloth big enough to loosely fill the conduit to the end of
a string. Then use a shop vac on one end to suck the rag and string
through the conduit. Then tie the string to a rope and pull that through.
You can then use the rope to pull the cable.

4. Put a little "cable lube" on the cable before you start pulling. This
is a waxy substance that really simplifies cable pulling, especially in
tight situations. Just don't get it on your hands or gloves or you won't
be able to hang on to anything.

5. Use electrical tape to secure the pull rope to the end of the cable.
Try to make the end of the cable "taper" a bit with the tape so there's
less likelihood of it catching on the conduit joints. Squirt a little
cable lube on the end, then have one person "push" the cable in the
conduit, while another "pulls" the rope from the other end. The person
pushing should do most of the work, the rope is mostly to help guide the
cable. Don't pull too hard or you may pull the rope loose from the cable.

Shouldn't be any problems, but if it seems to get stuck, just pull the
cable back a bit and try again. If you have a bend or two, it make take a
bit of jiggling to get the cable through the bends. Worst case, you can
pull the cable out and start all over again.

Good luck,

Anthony

dgreen368 via HomeKB.com

2007-02-13, 9:25 am

Thanks for all of the information. I'm going to slow down, contact the
engineer at the utility company and have him come out and review the
electricity supply point options with me. Then I'll involve a licensed
electrician to work with me to develop a plan that fits my budget and my
willingness to put in the sweat work.
Through this post and others here I've learned a heck of a lot. Thanks again.
...

dgreen368 wrote:
>Hello,
> I just purchased a 6 acre country property in West Texas and am building a
>small apartment (580SF). I didn't do a lot of research on supplying
>electricity to the apartment and had the electric company place a meter on
>the pole about 200 feet from the apartment. My intention was to trench and
>bury the service wire. Now I browse through Home Depot looking at wire and
>see some costing $5-6 per foot. Wow.
> Can anybody tell me what size wire I require to run this service? My
>intention was to in the future add another 1500 SF main home to this
>structure. I thought I would power the entire thing from the box in the
>apartment, but if the cost is out of sight I'll run service for the small
>apartment and worry about power for the main house later when it's built (2
>years).
> I have another pole that's about 120 Feet from the structure so I could
>possible eat the cost ($580) for the initial meter and have one brought
>closer.
> Does this make sense? Can anybody tell me what I'm looking at.
>
>Thanks
>
>Dave
>Worried out West

--
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