- Q. The proposed location for my client's new detached garage is right on top of a buried service-entrance cable. The electric meter is mounted on a pedestal about 100 feet from the house, and a conduit runs to the house through the area where the garage — which will have a stem-wall foundation and concrete slab floor — is to be located. The electric utility doesn't have a problem with the building's location because it is responsible for the line only as far as the meter. Is it okay to pour the foundation around the conduit so that it runs through the stem walls and underneath the new slab, or do the cable and conduit have to be rerouted around the foundation?
A.Joe Tedesco, a licensed electrician, a certified electrical inspector, and the moderator of JLC Online's electrical forum, responds: In general, the NEC doesn't permit service-entrance conductors to pass through the interior of another building unless they are protected by brick or concrete, or a specially constructed vault.
But in your case, as long as the conductors are enclosed in conduit and are buried at least 18 inches below grade, the NEC would consider them to be outside the building (2005 NEC 230.6).
In addition, the NEC considers these conductors to be outside of a building when covered by a concrete slab that measures at least 2 inches thick. So your existing service entrance is fine where it is, though it will make excavating the site and pouring the foundation a little trickier.