I was recently told of 480V 3-Phase wiring mistake made at a plant. The run was 3-350MCM per phase through 3-conduits. The mistake was that all of one phase was run in each conduit, 3-A Phase in one, 3-B Phase in one and 3-C Phase in another. The 3-conduits terminated into an electrical enclosure.
One problem was heat created at the enclosure where the 3-conduits entered the enclosure. The solution was to break the connection at the enclosure, in other words a rectangular area was cut out around the conduits where they entered the enclosure, thus eliminating the metal to metal connections of the conduit and enclosure.
The question is what was causing the heat build up at the conduit/enclosure connection?
And what consequences if any exist in the conduits that still have all of 1-phase run in each?
One problem was heat created at the enclosure where the 3-conduits entered the enclosure. The solution was to break the connection at the enclosure, in other words a rectangular area was cut out around the conduits where they entered the enclosure, thus eliminating the metal to metal connections of the conduit and enclosure.
The question is what was causing the heat build up at the conduit/enclosure connection?
And what consequences if any exist in the conduits that still have all of 1-phase run in each?