remote meter base and wire size

Started by rdzone, September 07, 2010, 04:22:45 PM

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rdzone

OK I am way out of my element here.  I don't know much about electricity at all.  That being said I am trying to save my self so $$$.   The Power company will run an electrical line from the pole to my meter for $19.00 a foot.  That seems outragous to me.  If I put in a remote meter base at the edge of my property and run the cable to the house it will only cost me the price of the cable and the cost of the excavation.  My neighbor is an excavator and said he could do it for way less money.  Probably 30-40 minutes to dig the trench.  I just need to buy the cable.  The engineer at the electrical company was very helpful as he knows their costs are high.  He spec'ed #2/0 urd cable for the distance from the remote base to the cabin. However I have no clue what #2/0 urd cable looks like so I am trying to gleen some info from you knowledgable individuals before I go to price cable.  Does this cable run from the circuit breaker panel all the way to the remote meter base?  Any information would be appreciated.
Chuck

muldoon

rdzone.  I am not familiar with the term remote meter base, but I think I get the gist of what your looking to do. 

At the edge of your property you have electrical service.  Instead of having the electric company run power into your place and connect to the meter at your house you want to have them connect at the edge and then you run the wire into your house. 

If that is accurate, I think the solution you want is a subpanel.

At the property edge, install your meter loop.  This would include the weatherhead, an 8' ground rod, a 200 amp service panel and meter.  Your electrical company will spec out exactly they want you to have for meter termination.  This would then be the place where "their" side ends.  Anything inside would be all you. 

As for how to hook up your house to the main panel, you would install a subpanel inside your house. 
Something from squareD load panel -
http://www.schneider-electric.us/products-services/products/load-centers/residential/qo-load-centers/

..
To size the subpanel, you need to determine how many circuits you will require and the total amps being requested.  Perhaps you want 150amps, perhaps 200amps, etc.  Whatever size you determine makes sense defines what wires you must buy.  Once you ascertain the amount of amps you could put on the wires, you consult the wire ampacity table to size it.

http://www.cerrowire.com/default.aspx?id=46

Since 2/0 wire was speced, I would guess that he assumed 200 amp residential service. 
2/0 - 195 amp
   
VERY important to note that these cables will be in conduit.  Conduit by definition will be consider a wet location.  You MUST use THHWN wire.  This is single strand wire, and you will need four of them.  black, red, white, green.  Your conduit must be sized to fit 4 2/0 sazed cables through it. 

Out at the main panel you would install a 220v (2 pole) 200 amp breaker.  This would feed your THHWN cables that then feed your subpanel inside.  Your subpanel inside would then provide service for your breakers. 

All that beid said, you can seriously injure or kill yourself by doing electrical work and not doing it properly.  You also can create risks of your place catching on fire down the road.  Lastly, you may never be able to sell the place if it is done sub-par (even if it works).   I would seriosly consider hiring an electrician - perhaps you can find one that will listen to your plan, let you do 90% of the work and he just comes out to do a check and make final connections.  Good luck. 


rdzone

Thanks for the input.  Your description is what I want to do.  I have the electric company's service assembly guide.  They call it a remote meter pedestal.  The cost of $19.00 a foot for the electrical company to run cable got my attention so I thought I would start researching things now.   

Don't worry I have a friend that is a licensed electrician and he said he would help.  I just haven't talked to him about this yet as he is on vacation.   
Chuck

MountainDon

2/0 urd cable..... URD = Underground Residential Distribution. It comes in triplex and in single conductor form. It can be direct buried or run in conduit. The power company is the final voice on whether or not you need conduit. Here they use it as designed, direct burial, 24" minimum depth. Yellow marker tape is used in the trench something like 6 or so inches above the wire.

FYI, in conduit the ampacity of the wire is reduced.

How many feet do you need?

I found 500 foot spools for $1200 plus a couple hundred shipping.  There are also other types of service entrance wire available but you would have to clear it with the power company or they may refuse to connect to the service.


Remote Meter Base... A housing the meter mounts to that is pole or pedestal mounted. The usual method is to have the meter head and service panel in the same housing or the meter outside and the service panel on the inside of the same wall. A remote meter allows the meter to be distant from the service panel. The power company feed enters and connects to the meter jaws and another wire set connects and feeds metered power through the underground wires to the distant building.

There would likely be a disconnect on your side of the meter at the pole, but not necessarily an entire service panel. Friends here have such an installation on a pole a quarter mile from the cabin. They have a disconnect at the meter as well as some big fuses. At the cabin they have another disconnect on the exterior side of the wall. Their service panel with all the branch circuit breakers in on the other side of the wall, inside the cabin utility room.


Hope that helps.


Just because something has been done and has not failed, doesn't mean it is good design.

archimedes

Is it possible to run the service wire a quarter of a mile?  I would have thought the voltage drop would be too great.
Give me a place to stand and a lever long enough,  and I will move the world.


MountainDon

You caught me exaggerating.  :-[   It's probably more like 800 feet. It's only a 100 amp service and it does use large wire. Not sure what but it is larger than 4/0.   :o    Originally he was going to build the cabin closer to the property line. Then he changed his mind and wanted to hide behind the trees. The large wire was still cheaper than having the power company relocate their end of the service.
Just because something has been done and has not failed, doesn't mean it is good design.

davidj

Note that the size of the cable depends on the distance _and_ the current as you need to limit the voltage drop and that depends on the length of the wire.  You get into larger wire sizes pretty quickly as the distance increases. 2/0 is pretty chunky wire - 1/3" across - so you're probably talking something like 2" conduit and serious physical effort to pull it.  Also don't confuse it with 2awg - it's 3 notches up in size - see http://en.wikipedia.org/wiki/American_wire_gauge.  This table also includes the ampacity for short conductors, but that only works up to a few 10s of feet so don't go by that for long runs.

If you start playing with a voltage drop calculator - there are several on the web - be sure to use twice the distance in the calculations as you lose voltage going out and coming back.  If you go for a smaller service you can end up saving a lot of money on copper.

I've been looking into this stuff for my generator setup and it starts to get pretty expensive as the distances increase - I wouldn't be suprised if you're looking at $10/ft or more for materials so the power company quote might not be too crazy (my 2awg setup comes in close to $5/ft for 240V).

According to my solar guy the ground can be one step smaller than the other cables and it can also be outside the conduit, but I'd double check that with the power company to see if it applies in your case.

MountainDon

Direct burial means no worries about conduit.  :)  It sounds like the power company is saying direct burial is fine since they are spec'ing the URD.  :)  The wire may cost a little more than anything that requires conduit, but it is simpler and less labor intensive and may actually cost less when wire, conduit, glue, etc. is added up.

data sheet
http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet39



Just because something has been done and has not failed, doesn't mean it is good design.

rdzone

When I talked to the engineer from the power company he spec'ed direct burial, 2/0.  He knew the approximate distance from where the remote base would be and the cabin.  He said he ran it through his magical calculator.  He also stated that no conduit would be needed, unless the power company ran the line, they use corflow.  He said offically he didn't tell me that.
Chuck


MountainDon

There ya' go Chuck. All you need to do is find a local supplier and price the wire or if you need a large amount buy a spool. Sounds like you can get the line in yourself for a lot less $$ than the union power company.
Just because something has been done and has not failed, doesn't mean it is good design.

archimedes

Just curious rdzone,  how long of a distance are we talking about?

This sites give you prices on their website.  Can't gaurantee that they're the lowest,  but at least it gives you a starting point on prices.
http://www.wesbellwireandcable.com/Electricalwire.html
Give me a place to stand and a lever long enough,  and I will move the world.

texasgun

You might check around with your local electric Co-op for wire. At our ranch were we are building we are not on a co-op but I am at our house where we live on the farm. The co-op allows me to buy wire at a very good savings even though they know it is going to my ranch that is not covered by our rual co-op. Last time I bought service wire I got 300 ft and it was 1.50 ft. Dont remember what size but huge 3 conducter aluminum that barley fit in 2 inch condiut. They told me what size I needed and even told me how to do it knowing it was being used with another electrin company. I used condiut anaway even though it was direct burial, my thinking at less them .30 cents a foot condiut is good insurance against future problems like sticking a shovel or posthole digger threw on of those cables. Everyone should always check and make sure your area isnt covered by a co-op the cost for me to run 980 foot of overhead to my new barn at the farm where I live was $520.00 to cover the service loop with the co-op. I ran 900 foot foot at the ranch and had to supply my own service loop and pole and the cost was $2880.00. But again that is the differnce between a co-op and the eletric company. Even if you just have a friend or relative on a co-op they should be able to buy your wire at member price.
WEST TEXAS

rdzone

Everyone thank you for the great information.  I knew if I asked, even a dumb question you all would straighten me out. 


Bmancanfly - I think the engineer estimated around 200' of wire from the remote base to the cabin.

Texasgun - My electrical company is a co-op, so I am not sure if they would let me purchase cable or not from them.
Chuck

jbos333

Last I checked 4/0 alum triplex w/ground was about 2.50/ft at the big box stores around here. It was actually more pricey when I put service in to my pole barn.

One thing you should consider - be VERY sure you won't want to extend the service farther in the future, for another cabin, shop or whatever! I currently am having quite an issue with this myself as my pole barn is 350 ft or so from the road/meter. So I have 4/0 feeding the panel in the pole barn. It is a pass-thru panel so I could continue the service. Originally I didn't think I was going to build a cabin/house more than 200 ft from the pole barn, which would have been fine......but, of course, I have found some really great building locations elsewhere on the property-at 350 ft, 550 ft, and 900 ft away! So I am going to have to redo my service, or add an additional one with a second meter (and pay the minimum $17.00 per month on both).


JRR

You are lucky that your sevice company is so co-operative.  I wanted to have a meter installed on my property line, outside driveway gate, on a post or something .... but was told "no can do .... the meter must be installed on the main residence building and the meter maid must always have access".  Dumb!!  Guess they want to make it easier for vandals.

bayview


  I notice a lot of entrance/service cable is aluminum . . .    Is this ok to run from the meter to the breaker box?   You hear a lot of negatives to house wiring that was aluminum.  Outlets and switches got hot.   With a possibility of creating a fire . . .

  How many wires/cable needs to be run from the meter to the box?   Two hot with a third wire for the neutral/ground?   Or, two hot, neutral and a ground . . .   For a total of 4 wires.

  2/0 wire is rated for 195 amps . . .    Is that per leg?  If so, for a 200 amp box, couldn't one run #3 wire that is rated at 110 amps?  That would be two hot #3 wire, and a #3 ground/neutral . . .   For a total of 220 amps.  

  I guess my question is, on a 200 amp breaker box, is the main breaker 200 amps per leg, or does it have a total of 200 amps?  In other words, is a 200 amp breaker box have a total of 200 amps?   Or, a total of 400 amps? - 200 amps per leg . . .

/.
    . . . said the focus was safety, not filling town coffers with permit money . . .

rdzone

Bayview

some good questions.  I hope someone has some answers.   :)
Chuck

MountainDon

First here's what I do know....   ::)

Aluminum can be used for service entrance wire and other wiring. Proper installation uses an antioxidant compound and the connectors have to be designed for aluminum. You will see some electrical equipment marked "Al/Cu". As well proper torque must/should be applied to the screws, something that most DIY'ers do not do. I use one of my gunsmithing torque tools.

If aluminum is used in place of copper the wire size has to be larger for the same current.  Also note that ampacity varies with what temperature rating is used.

When mounting a meter head remotely, there is a maximum distance between meter and service panel before one needs to have a main disconnect at the meter. Twenty five feet comes to my mind but that could be wrong.

When the main disconnect is at the meter then 4 wires must be run from the disconnect to the service panel. Two hot, one neutral and one ground. The ground between the power company and the meter is provided by the metal ground rod driven 8 ft into the ground at the meter location..

Regarding service entrance wire sizes... Anything I've ever looked at regarding a 200 amp service panel states something like "2/0 copper OR 4/0 aluminum would be the correct choice for a 200 amp service".   Not much detail given as to length of wire. Mostly the wire size from the power company to the meter and service panel is spec'd by the power company. Most of the time the meter and panel are quite close together. Separation gets into more detail.

At 90 degrees C, the charts do rate 2/0 aluminum at 150 amps and 2/0 copper at 195 amps.

Just because something has been done and has not failed, doesn't mean it is good design.

MountainDon

Now the color becomes, fuzzy, gray....


I have always thought that a 200 amp main breaker was sized like any other breaker. A double pole branch circuit breaker, that is labeled as 20 amp, will protect each leg up to 20 amps. The legs are independent. Therefore I thought that a 200 amp main breaker, which has two legs, would be able to pass 200 amps per leg or per pole. But that could be flawed logic, I don't know. So why isn't it called a 400 amp panel if that is the case?   ??? 

Another thought that can confuse things is that a typical 200 amp panel contains 40 slots. If each slot was filled with a 20 amp breaker that would calculate out to 800 amps.  more ???

Along similar lines, our cabin panel uses a double pole 30 amp breaker as the 30 amp mains breaker. That places up to 30 amps available to each leg, even though there is only a maximum of 30 amps available to the panel (from the inverter).


Looking back at the original info there are a few things missing, or not specified. While it is true that a given gauge of wire is rated for X current as the distance becomes longer there is more voltage drop at the load end. So sometimes wires are oversized to cut down on the loss. I'd ask that power company engineer what voltage drop maximum he was calculating for. Three percent is an ideal goal, while I believe 5% is looked at as acceptable. And what was the maximum load that 2/0 is supposed to carry in his calculations.

Just because something has been done and has not failed, doesn't mean it is good design.

Shawn B

MountainDon,

I asked an electrician the same question, while sizing a generator hook up. He told me that load centers are designed based on only a certain number of circuits drawing amps (in use) at any one time. I can't remember the percentage he said though  ???   d*  Also keep in mind that even a 20a circuit (or any circuit) should only draw 80% or 16a. Plus there are many dedicated circuits being used in modern load centers-----furnace, dishwasher, fridge, freezer, sump pumps, etc.  Rarely do these draw anywhere near the 15a or 20a that their breakers are sized at. It's more about not having a short, or over current condition in an appliance, not knocking out power to other appliances or circuits.

On 200 amp breakers they, and others, usually trip at 15-20% above their rating.

*NOTE* I am not a licensed electrician
"The natural liberty of man is to be free from any superior power on Earth, and not to be under the will or legislative authority of man, but only to have the law of nature for his rule." Samuel Adams


MountainDon

Quote from: Shawn B on September 09, 2010, 06:57:17 PM

I asked an electrician the same question, .............  . load centers are designed based on only a certain number of circuits drawing amps (in use) .......



I couldn't find my tongue in cheek emoticon regarding my 800 amps figure.  .   ;D ;D  I know,,,,,  I threw that in more or less to make it more obvious that what one sees on the surface is not always what the whole story is or some mixed up other metaphor for sometimes it doesn't make sense or add up.  ???  


There's always a lot of safety factor built in... unfortunately there is always someone who will push harder than the engineer thought possible.

Just because something has been done and has not failed, doesn't mean it is good design.

bayview



   Thanks for clearing that up!    ;D

/.
    . . . said the focus was safety, not filling town coffers with permit money . . .