I agree with you about bury, it has different connotations than "soterrar".

I have found these references that I hope may help:

Sierra Pacific Power Co. has finished moving a 2,000-foot section of its overhead power line underground in downtown Tahoe City. Underground facilities have been installed from Grove Street east to the state park along North Lake Boulevard.
The utility is currently removing the tops of the 20 power poles that supported the electric line, according to Sierra Pacific's Chris Daley, manager of district operations for North Lake Tahoe. The poles will be removed entirely after the remaining cable television and telephone lines are moved underground to serve the downtown business district
Section 10-107 Overhead and underground construction.




Construction of the trunk, feeder and drop cable may be overhead where poles now exist and either electric or telephone lines are now overhead, but where no overhead poles now exist, all trunk, feeder and drop cable shall be constructed underground. Whenever and wherever either electric lines or telephone lines are moved from overhead to underground placement, upon reasonable notice to franchisee, all cable television cables shall be similarly moved and the cost of moving the television cables shall be solely the obligation of the franchisee.


(Code 1964, § 21.210; Ord. No. 12192, § 1, 4-3-89)