| (none) | Gresham | United States |
| (none) | Serra | Brazil |
| (none) | Cupertino | United States |
| (none) | Colleyville | United States |
| (none) | Downers Grove | United States |
| (none) | Knoxville | United States |
| ABB | Stonehouse | United Kingdom |
| ABB | Mount Pleasant | United States |
| ABB | Cary | United States |
| ABB | Allentown | United States |
| ActewAGL | Canberra | Australia |
| Advanced Control Systems Inc. | Norcross | United States |
| AES Corporation | Hiawatha | United States |
| Al-Khudri | Candiac | Canada |
| Alabama Electric Cooperative, Inc. | Andalusia | United States |
| Alaska Electric Light & Power Co. | Juneau | United States |
| Alborz Microsystem | Tehran | Iran, Islamic Republic of |
| AltaLink Management LP | Calgary | Canada |
| American Transmission Company | Cottage Grove | United States |
| Ametek Power Instruments | Coral Springs | United States |
| AnyGate Corp. | Seoul | Korea, Republic of |
| Applied Systems Engineering, Inc. | Campbell | United States |
| Apterra Technologies, LLC | Stow | United States |
| Areva T&D | Bethlehem | United States |
| Areva T&D | Stafford | United Kingdom |