The DB2-420-40LNE is designed to protect 3 Phase systems for the home / Office / Factory from surges that travel along a Line Input power lines. This is the only device of it's kind that will glow as an indicator that the Surge Protection is still functioning inside DB board. If the DB2-420-40LNE stops glowing, it indicates it needs to be replaced. The DB2-420-40LNE is easily identifiable by its transparent Red housing.
This product must be installed by a qualified electrician.