- Advanced Protection Technologies (APT)
- Bryant Electric, Inc.
- Emerson Network Power
- Cooper Bussmann
- Eaton Corporation
- Emerson/EGS Electrical Group
- ERICO, Inc.
- Ferraz Shawmut
- GE
- Hubbell Incorporated
- Leviton Manufacturing Co., Inc.
- Littelfuse, Inc.
- MVC/Maxi Volt
- Pass & Seymour/Legrand
- Phoenix Contact, Inc.
- Raycap
- Specified Power Devices (SPD) Corp.
- Square D Company
- Surge Suppression Incorporated
- Transtector
- Current Technology – Thomas & Betts
- Technology Research Corporation