Buried Power Lines

[chicopee]

Two questions about buried power lines: 1)Is the depth of such power line to be below the frost lines? 2) since there will be some heavy truck traffic over this power line and I expect that the soil will be saturated with storm water and snow melt, what would be the suggested protective casing material thru which this power line will be laid .

 

[melspuds]

chicopee,
For the National Electric Code, the depth of the line depends on voltage,if under 1000 volts a could bet is 24" is the minimum and for truck traffic is the same. In most jurisdictions require conduit for traffic. Check with the local AHJ and power utility for both questions.
Hope this helps;
Dave

 

[chicopee]

Since frost heave is my major concern, will that mechanism uplift the buried piping in saturated soil?

 

[krisys]

Hope you are talking about the underground power cables and not the pipes.

For the power cables there are no such arrangement as standard. If such special requirement is there, it shall be engineered to address the specific issue.

 

[melspuds]

Is this for a electrical utility service? If it is then contact the utility. If frost heave is a major problem, then go deep. Without knowing the local conditions and codes, I can not say. Again, check with local AHJ, utility, or a contractor. Frost heave can really tear cables or conduits apart. The NEC only states that with frost heave protection must be used to protect cables and/or conduits from damage. See NEC Articles 300.5 and 300.6. Again check with local authorities (AHJ).
Hope this helps;
Dave

 

[cranky108]

I think a few people may not understand that utilities are not required to follow the NEC. Utilities are required to follow the NESC.

Frost heave may be an issue, or with plastic conduit, it may not. The depth of the power lines may also be dictated by soil conditions, such as rock, or water table, or if placed in a common corridor may be just below the sidewalk.