The control, monitoring and signaling units SA ..., CTB ..., CSTB ... and CTBE ... include a series of enclosures with “Ex tb” protection available in aluminum, polyester or stainless steel and in different measures. According to the size and the material chosen, there are three maximum dissipation limits that correspond to each of the three maximum optional ambient temperatures: + 40° C, + 55° C and + 60° C. Several IECEx/ATEX certified devices can be mounted on the enclosure faces and a glass or polycarbonate window can also be fixed to the lid. Various electronic devices can be installed internally with a total power dissipation within the limits defined for each housing such as terminals, analog and digital instruments, control and measurement devices, circuit breakers and IECEx / ATEX certified battery packs. SA/SS series stainless steel command and control junction boxes may be provided for ‘Ex tb’ panels on request.