yesterlectric
Senior Member
- Location
- PA
- Occupation
- Electrician
Anyone know from experience a good method for maintaining separation between high and low side conductors when installing a pad mount transformer that has primary over 1KV and secondary less than 1KV and using an open bottom box pad (with conductors stubbing through the bottom) like shown here? 300.3C2 allows the MV & LV side to occupy the same enclosure, but only at the xfmr, not at the "vault" (box pad). Article 450 has nothing on this that helps. Article 110 as rules for manholes, which this is not.
A partition to separate the MV&LV sides isn't so desirable as it impedes the service loop for the 35KV cable. A conduit stub up in the vault for the LV conductors isn't so desirable either as it can be subject to breakage, and also makes for less termination bending radius for the conductors' connection to the xfmr spades.
Utilities likely do this all the time without consideration, but NEC applies to non-utility installs, and article 300, at least as written, requires separation.
A partition to separate the MV&LV sides isn't so desirable as it impedes the service loop for the 35KV cable. A conduit stub up in the vault for the LV conductors isn't so desirable either as it can be subject to breakage, and also makes for less termination bending radius for the conductors' connection to the xfmr spades.
Utilities likely do this all the time without consideration, but NEC applies to non-utility installs, and article 300, at least as written, requires separation.
