Power-Lock Industrial Specification Grade Locking Devices - Receptacles 3030/20A, 250V DC / 600V AC Non-NEMA 4-Pole/5-Wire. Power-Lock devices are designed for safety, energizing within a chamber to eliminate the possibility of exterior arcing. They are ideal for high-abuse industrial and specialized hospital applications. Cat Nos.: Receptacles 25403 (In Cast Iron Cover and Steel Shell, Black) and 25250 (In Cast Aluminum Cover w/Weather Protective Lift Lid, Black)