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Installing an Underground Electrical Service and Pull Box

By Dave Rongey - Summary:

How to Install an Underground Electrical Service for a Home: Electrical Pull Box And a PVC 90 Degree Sweep to the Panel, Electrical Code about a Main Electrical Service Disconnect Switch.

Underground Electrical Service for a Home

Electrical Question: Dave, I worked in the electrical trade for years, but being retired for 8 years, I am faced with an electrical question.

  • I am doing the underground for my new home.
  • The meter with a 200amp disconnect is up the hill from the home.
  • I have about 160 ft to the bottom of the hill where I want to put a pull box for the incoming conduit (3 ” PVC).
  • From there it is 70 ft to the home where the load center is in the garage.
  • A 230 foot length of PVC conduit is too long a pull for me.
  • Can I put a pull box there instead of a PVC 90 degree sweep?
  • Do I have to have a disconnect on the outside of the home seeing that I have a disconnect at the meter.
  • The location of the main panel is not insight of the home.

Thanks Dave

This electrical wiring question came from: Robert, from Coos Bay, Oregon.

Dave’s Reply:
Thanks for your electrical wiring question Robert.

How to Install an Underground Electrical Service for a Home

Electrical Pull Box And a PVC 90 Degree Sweep to the Panel

  • Robert, it sounds like you will have quite a pull from your primary electrical service to the home, so I can understand why you would like to put in the pull box before the sweep, and yes, this is allowed.
  • At some locations I have installed pull boxes very close to the electrical panel where there is a long run of conduit, especially in locations where it will be must easier to pull from using a pull box rather than pulling into the panel.

Electrical Code about a Main Electrical Service Disconnect Switch

  • The home will most likely be treated as a detached building, so yes the provision for a Main Disconnect will be required.
  • ELECTRICAL CODE:  A Main Breaker is required when there are more than 6 circuit breakers in the building panel, or when more than 6 circuits need to be turned off for all of the circuit power to be disconnected at the panel location.
  • Install either a Main Breaker inside the panel, or a Disconnect Switch outside the building or inside nearest the point of entrance to the building.
  • The panel board must be listed as suitable for use as Service Equipment.

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4 Responses to “Installing an Underground Electrical Service and Pull Box”
  1. Robert says:

    Good Day,
    I have recently bought an older home which was built in 1990. Just before the air conditioner starts, all the lights in the house dim. Actually I would never have known because the lights are never on during the day, but they dim for a very short period of time of a few seconds when the a/c unit starts.
    This I would presume is due to the load being taken by the a/c unit. Question: is this normal, and if not are there any safety issues that I need to address?

    Thank you,

    • Dave Rongey says:

      Hi Robert,
      Motor loads, such as an air conditioning unit, do require a lot of electricity to start. In fact, air conditioners could draw up to 4 times the running amperage when they start, so when the air conditioner starts you may see some lights dim a little.

      Here are some other things that could cause your lights to dim when your air conditioner starts:
      The size of the home electrical service panel. If the electrical service is too small it may need to be upgraded.
      The size of the home, and other electrical circuit loads such as electric water heater and electric range or cook top.
      Is the home located in a rural area where the electrical utility service is weak, or experiences low voltage.
      The age and size of the air conditioner, and when was the last time it was serviced.
      Has the air conditioner been replaced with a larger unit, and if so, does the new air conditioner require a larger electrical circuit.

      I hope this helps,

  2. Dacey says:

    Installing underground electrical wiring is very difficult task and it needs lot of protection and safety.So a good company should be hired for the protective and proper wiring system at your home

    • Dave Rongey says:

      I totally agree!
      It is essential that every electrical project is well though out and installed correctly from start to finish in all locations including Somerset, Taunton and Bristol areas of the UK where you may consider contacting an Electrician in Taunton Somerset at R&D Electrical Solutions Ltd, 2 Dowell Cl, Taunton, TA2 6BA Somerset T:01823 253662 who will assist you with your home electrical projects.

      Remember: Do It Right the First Time, you will sleep better at night – otherwise please make sure all your smoke detectors have a fresh battery!

      Dave Rongey
      Home Electrical Wiring


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