This happened quite a few years ago (I seem to recall about 1966-67).
On a Chevron Chemical Co. site in TN, a 5kv direct burial cable was installed in PVC by the EC. Burial depth was 48”. He felt he was doing the owner a favor in that the cable could be replaced with ease. A few years later, the cable failed. When the lawyers got through, the EC, an upper medium size, was forced out of business. The bottom line was even though the owner OK’ed the installation the EC was liable as he should have known that the amp capacity of the cable buried in earth depended upon the effects of the earth being in contact with the cable. The installation in raceway derated the ampacity of the cable.