I live in Utah and have a couple of questions. I have a 150 amp underground service and the circuit box is full even with double breakers. I am adding onto my house, needing to move the 150 amp service and will increase it to a 200 amp service. The power company is OK with this work as moving the meter to the side of the house is preferred to the back of the house where it is currently located. All I need to do is dig the trench and lay the conduit with a pull line. The power company official told me to use 3” conduit. This seems extreme as the residential meter bases have 2” connectors slots at best. Is there some code about this conduit size? I wonder if the official was thinking non-residential with a need to pull more wires in the future. My second question is can I keep the 150 amp circuit box and add a box onto the side of it or do I need to replace the 150 amp circuit box with a 200 circuit amp box?

Thanks,

Terry

This is very common for the utility to have jurisdiction over the details for an underground service. They insist on larger than required conduit, by the way the min size conduit per NEC is 2 ", for several reasons. One is to have a large emough conduit in place for future expansion. The length of the UG runs they deal with have casued them to be sure conduits are larger. They also need to insure the conduit will not damage their cable.

You also need to consult with the utility for the make and model number of the meter sockets they have approved for thier meters. They recognize that a meter socket may not accept a certain size conduit, I will be surprised to find that they did not already take this into consideration.with a certain socket ready for 3" C or a reducing connector that they recommend.

Regarding the panel, check to be sure the panel is not already rated for 200 amp, it may be. If it is a 150 amp panel, then you do have two choise, either change out the panel to 200 amp, or as you suggested, keep the exisitng panel and add as necessary.

I believe that changing the panel to 200 amp will be the least expensive and easiest to do.

If you come in with a 200 amp feed,and keep the existing panel, you must first have a 200 amp main breaker someplace, then feed into two additional breakers, to split or distribute the 200 amp to 150 and 50 amp.

Because of the cost of the additional breakers, their enclosures, and the installation, I do not think this is very practical, or less expensive.


Following is a link to Pacific/Utah Power, you can review their requirements.
http://www.utahpower.net/Navigation/Navigation552.html
You will see that they specify a certain meter, and the meters I have found all have 3 " KO on the bottom when rated for UG.

Thanks for the follow-up... just what I was looking for