New Electric Service Question??

[Ezzie]

Looking for some advice from any forum members with experience installing new service entrances. My shop is located about 300' from my closest property line to where there is power. I want to install a new dedicated 200A service with meter since it is a lot closer than my house (which currently has only 100A and is about 500' away).

I have the ability to do my own trench (own a backhoe) and I also want to run a natural gas line in from the road as well (for a radiant floor heater) so I will want to bury both the gas line and power in the same trench while I have the ground open. I spoke with the gas company and they are OK with this, they have specified the trench width/depth, seperation and back fill conditions.

The problem came when I called the power utility to arrange for a site plan. They are telling me that 300' is too far to run a 200A/220V service entrance and say I will need to install a primary line (underground) to either a pole mounted xformer or a slab mounted unit. The U/G wire they spec. is a 2/0 28kV with a concentric neutral and I have to pay for the whole damn thing right from their utility pole at the road (with one exception - if I go with a pole mounted xformer, they supply the xformer at N/C). They say I need to have an electrical contractor look at it and go over the various costs with me and then once I have decided what I want to do, get back to the utility and they will come and do a site plan.

WTF - is this a crock or what?? Seems a bit excessive just for a simple 200A service for a stand alone building in which to play with my toys. Can't they (or me) just use a slightly bigger conductor from the road to compensate for any additional line loss due to the distance (seems to be their big concern). I would think this would be a lot cheaper than doing the primary to xformer thing. I am also concerned about xformer noise since the install location would be close to my neighbour's pool.

 

[Tscott]

I work at an electric utility, and the rules here will no doubt be different where you are, but this is not an unusual thing. 300' is a long way to run a URD service, but it can be done. They are trying to avoid a large voltage drop. What kind of loads are you expecting in the shop? large motors (i.e. air compressors) will cause flicker problems if the service is too long and the wire not large enough. Are you running AC ? This is another large load.

Here I try to limit my service runs to 150' or less. I will regularly stretch this to 200' with up to 4/0 wire. Anything longer usually requires 350 wire to be run. However the problem we run into is that the standard 200A meter base will only accept up to 4/0 wire. To use larger conductor we must use a 320A meter base. Could they run a 1Ø Over Head tap from the existing pole on your property line to a location nearer your garage? If this is an option it would likely be cheaper than under ground.

Keep in mind that the way utilities make money is by selling power to customers. In order to do this we have to spend large amounts of money to build infrastructure. We then depreciate this investment of capitol over a period of up to 60 years. A house has a good amount of load during the day, due to air conditioning heat etc. but your garage is a big question mark to these guys. Most likely your garage will not generate the revenue your house does, and therefore if they were to put all this stuff in for free, they would never see a return on their investment. IF they did this all the time then electric bills would go through the roof in order to pay for this. We pay taxes on every piece of equipment we put in the ground. Every transformer, pole, foot of wire, every bolt. Sit down and talk with them and go over all your options. Their goal is to sell you power, but they will not do it at a loss.

Hope this helps,
Tom

 

[Ezzie]

Thanks for the insight Tom.

I have some typical loads I want to run - everything is single phase.

220V stuff: biggy is a 5HP air compressor with a mag start (60A in rush), 125A MIG, hydraulic auto lift (2.5HP motor), 5HP (30A) electric power washer.
110V stuff: 5x 250W MH low bays + approx. 20 4' T8 flourescents, various grinders, beer fridge, microwave, coffee maker, etc. I've also got a 30A drop to a sub panel approx. 150' away to my wifey's horse barn to power the lights and water bucket heaters.

I currently have the air compressor in another out building close to the house on the end of about 75' of 6/3 (from a 60A breaker in the 100A house panel) and that sucker makes the house lights dim when it starts.

In adding all this up, I see their point and probably can answer my own question. I am a bit suprised that 300' can result in such a significant voltage drop but I'm here to learn. I think I need to bring the primary in at from the road to a transformer near the shop and bite the bullet on the expense to ensure it is done right.

A few more questions if you don't mind - I've got to decide where to put the transformer so it isn't too close to my neighbour - I don't want any noise from it ******* him off.

Is the cost/ft. of running medium voltage (14.4kV I think in this case) more or less expensive than the low voltage service wire? This might help me to decide where to locate the transformer, ie. longer run of med. voltage vs. shorter run of low voltage.

Cost of overhead wire and a couple of poles vs. going underground (I have a backhoe so can do the groundwork)?

If I'm going to the expense of putting a transformer on property - would it be significantly more expensive to bring in 400A instead of 200A and then split it at the transformer for the two buildings - say 200A to the shop and 100A to the horse barn?

If I did this, could I go on a common meter at the transformer or do I need a meter base on each building?

 

[SteveU]

Local utility here charges 6.00 per foot for underground electrical service, not sure what it is for above ground.

 

[Ezzie]

OK, thanks for that suggestion. Installing a pedestal meter at 200' from the transformer would work well. I could probably get them to run 4/0 to it and then run 2/0 to the shop another 100' and a second feed to the horse barn about 60' so I can get 60-100A in there as well, both on a common meter.

 

[JDMopar]

Tom pretty much summed it up. I work for a power company too,and as Tom said,everyones rules are different. To answer your concerns about the hum of the pad mounted transformer bugging your neighbor,they will never hear it. To see for yourself,go find a subdivision that has powerlines underground and get out and listen to one. They are generally a dark green metal box about 3-4 ft square. You have to be standing right over the top of one to hear it. At the company I work for, we will run 350 UG tpx wire the distance you need,and never have any voltage drop problems. However,we keep our voltage a little high coming off the regulators to eliminate that problem.Good luck with your new shop

 

[Ezzie]

Just a follow up on where this is heading. I had the utility planner by today for a meeting with a local electrician to decide what to do. My meter base is 335' from the property line. If you include the run up the pole to a transformer, it is over 350'. They said "no way" to a 200A service and "OK" for a 100A service. I can't live with only 100A so I've got to go with bringing in the medium voltage to a pole with transformer 200' in from the property line and then do my service entrance underground from there. I wanted to stop at the 200' spot for the transformer since in the future I may need another 60 or 100A drop over to a proposed new horse barn at some time in the future. They said they can run the overhead 200' span without any pole in the middle (wow!!). They have spec'd 40' poles. I am eagerly awaiting the electrician's quote (about like waiting to have a barium enema done).