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These companies don’t just make this stuff up for the heck of it!! They install it in a certain manner because they know it is safe and works over the long term. This is part of our company business, so I am very familiar with this. I would suggest you do it their way or don’t do it at all.
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These companies don't just make this stuff up for the heck of it!! They install it in a certain manner because they know it is safe and works over the long term. This is part of our company business, so I am very familiar with this. I would suggest you do it their way or don't do it at all.
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The only aspect in which I've challenged the "specs" to install underground electrical service is in regard to required conduit size.
My own house required a 540' run. The elec company required 4" conduit for the elec. They couldn't justify why 4" was required, after a few phone calls they "allowed" 3 inch. Saved a few dollars in materials in the end. If, however, this isn't your own house, I'd do what they want and pass the costs downline. Consider it just another building cost.
I put the 3" elec on one side of the trench, and two 2" runs on the other side, one for phone, one for future use.
As far as trench depth, trench lining (sand), etc, I wouldn't mess with their specs, especially if, as you mention, you have rocky soil.
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Do it their way! The extra money you spend now is a lot less than what you will spend to fix it when it goes bad.
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To add to the chorus: Do it the utility company's way! Up front cost isn't the issue; long term safety and reliability is.
*Primary 18" deep!! Talk about a liability suit. Actually I have never heard of the customer for a residence installing the primary for a URD installation. Secondaries and drops yes but not primary. What about the transformer? You have to install that too? The other guys are right in that it must be installed according to the power company specs. If not then they can refuse to connect the power. Then you would have to reinstall everything. What specs do they have and maybe I can give you a comparison as to what the power company I work for requires. Just to give you an idea, our primary 20KV is installed about 4'deep in 3" SCH80 PVC. Our secondaries are around 24" deep in 3" SCH 80 PVC.
*In NY you must go with their specs for the primary which they install- It's 3' deep, 6" sand at the bottom, no conduit if sandy. They are responsible for failures of the primary up to and including the transformer. (except of course if you dig it up etc.)It's also a law here that they must go 100' for free. If you put in a post and meter at 100' you can run secondary to the house up to ~300' and still meet max voltage drop requirement. You can install the secondary yourself - to code of course.If there are two nearby houses in NY, the power co. must go 1000' for free overhead. You can negotiate about underground service, such as you provide trench and backfill, while they drop the cable and conduit, and provide transformer.Hope this helps - be sure to do it right as the other posters have suggested.Good luck!
*I should have added that this was the secondary, from the elec companies box to my meter. Trench was 4-5 feet deep. No one I know of messes with the primary.
*In & around rochester NY they will go 1000' for free, then you pay. If you want it buried you pay for the trench. You also give them a right of way along this route.-Rob
*'sounds like you don't have a choice but to do it their way. Once it's installed, the utility will own everything up to the meter, and is responsible for maintaining it ('good thing, you don't want to mess with HV cable). So they call the shots.Around here, if the ground is rocky or even semi-rocky (hard inorganic clay), or goes under a driveway, the utility will want PVC conduit to protect the insulation. Insulation bruised by rocks can "leak" current. In any case, they want it 3' deep. They'll let the owner dig the trench and provide the xformer pad, but they lay the cable (and won't hook up power until the trench is covered).Also, 200' for the secondary sounds long. it may be code, but with longer drops the lights are more likely to blink and the TV picture to get squeezed whenever the AC compressor (or other big motor) kicks in.
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Have a VERY rocky site that I want to install underground power to. Installing according to local utility company's specs is way too expensive. Would like to bury primary along edge of driveway about 18" deep to within 200' of house site, then secondary for the remaining distance. Any advice regarding how to do this properly and safely? Thanks.
*Aren't you required, by utility regulations, to install to their specs?-Rob