I have a part with RP-5A on it, what is that? RP-5A is a 4 wire thermal protector used in several Downlighting fixtures. The leads are black, white, blue and red. It can be ordered as code *187HXX - RK1 CE00210 THERMAL PROTECTOR 4-WIRE U. Thermal Detectors Rev 2010.pdf (200 KB) Have more questions? Submit a request 0 Comments Please sign in to leave a comment.