Reference pickedObj = sel.PickObject(ObjectType.Element, "Выберите элемент");
ElementId selectedId = pickedObj.ElementId;
Element element = doc.GetElement(selectedId);
List<double> _value = new List<double>();
foreach (Connector connector in ((FamilyInstance)element).MEPModel.ConnectorManager.Connectors)
{
var mepConnectorInfo = connector.GetMEPConnectorInfo();
var parameterValue = (DoubleParameterValue)mepConnectorInfo.GetConnectorParameterValue(new ElementId(BuiltInParameter.RBS_ELEC_APPARENT_LOAD));
var value = UnitUtils.ConvertFromInternalUnits(parameterValue.Value, DisplayUnitType.DUT_WATTS);
_value.Add(value);
}