Guardian Auxilary Transfer Switch Contact Kit p/n 5621 The auxilary transfer switch contact kit allows a single large electrical load to be locked out from the generator operation. If a home is equipped with electrical heat or multiple central air conditioning units, this device allows the generator transfer switch to interrupt the control wire, breaking the signal needed for the appliance to turn on. Installation Information Once installed, the control wire must be run from the appliance to the transfer switch to connect to the contact.