Are 2 or 4 locknuts required if I use a RMC close nipple in this situation:
Two small dry-type tranformers are bolted together (back-to-back) and a close nipple used a a raceway between the transformers. There is about a 3/4 inch gap between them, which is too long for a chase nipple. A ground wire is pulled between the two transformers and terminated properly. Article 250.97 does not apply because the voltage is only 120vac to ground (230 phase to phase). Insulated bushings are required because the wire size is #2AWG.