An example apparatus includes a terminal block couplable to an electronics cabinet or mounting rail. The terminal block defines a first receptacle to receive a first circuit and a second receptacle to receive a second circuit. The terminal block includes an integral relay. The integral relay includes a first contact and a second contact. The first and second contacts are externally accessible relative to the terminal block. The integral relay further includes a first switch and a second switch. The first and second switches are electrically coupled between the first and second contacts. The first and second switches are respectively movable between corresponding open and closed positions. The first and second switches are independently testable to verify the respective operability of the first switch and the second switch.