I might be stating the obvious here but most control ladders don't have all of the relays and pilot devices active at the same time. For instance, I won't see, "OFF", "ON SUPPLY", and "ON EXHAUST" active at the same time. Same with high and low speed or time delay and run modes. You just have to consider your highest current draw condition and make sure you have enough ctl transformer to handle it. While it usually doesn't matter which 2 phases you pick, it is a good practice to monitor the health of the phase you aren't using. Before phase loss monitors (and voltage and rotation) from Time Mark, Diversified Products, Square D , Et,al. became common, relays were used to monitor the other primary combinations.
Joe
