A non-defeatable magnetically actuatable switch device is shown and described for restricting access to industrial controls. The non-contact switch device employs one or more non-contact access switches, and an access key removably disposed in close proximity to each access switch. Removal or installation of an access key alters the electrical state of a corresponding access switch. A connected control unit determines a mode of operation, or grants permissions, based on the combination of access keys that are present or absent from the device. A lockable or sealable cover is provided over the access keys to limit unauthorized access. A tamper detection switch is also provided for the sole purpose of identifying foreign magnetic sources in the vicinity of the access switches to ensure that the device is non-defeatable. Furthermore, all access and tamper detection switches are magnetically actuatable and thus provide a completely contact-free means of securing and restricting access to sensitive controls and parameters.