These CURRENT MONITORS can be used to detect either over or under current conditions. When the current is greater than the rating of the model chosen, one of our standard or split core current transformers (CT) can be used in conjunction with the relay. Select a window size which will accommodate the size of the conductor which will pass through it. Then select the primary amperage based on the nominal current flowing through the conductor. If the load being monitored draws 60 amps at 240vac, the CT should be rated 60 amps with a secondary of 5 amps. The same CT can be used for a motor load of 60 amps at 600 vac. Our CT's can withstand the six to ten times starting current drawn by a motor load so you don't have to oversize them. They'll also work equally well at all voltages up to 1000vac. For voltages exceeding this value, use one of our medium voltage models.