Autodetection of presence of internal CT burden on plug-in CT
Connection of shunt can be automated using a 3-pin connector.







simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. (a) With internal burden the CT's AC out feeds directly in. (b) When the meter's internal shunt is required a loop in the CT plug provides the connection. (c) The internals of the meter.

Wire a loop between AC and SHUNT on the connector of those that don't have one. Leave it open otherwise.