| Business | Phone |
| Commercial Alarm Systems 469 W Fullerton Ave, Elmhurst 60126 | (630) 832-2844 |
| Grimco Inc 747 N Church Rd G5, Elmhurst 60126 | (630) 530-7756 |
| Lab-Volt Systems Inc 442 Oak St, Elmhurst 60126 | (630) 832-3844 |
| Meters & Controls Inc 505 Wrightwood Ave, Elmhurst 60126 | (630) 279-3800 |
| Pentegra Systems 650 W Grand Ave, Elmhurst 60126 | (630) 941-6000 |
| Preon Power 445 W Fullerton Ave, Elmhurst 60126 | (630) 516-1284 |
| Stolley & Orlebeke 523 W Wrightwood Ave, Elmhurst 60126 | (630) 834-1320 |
| Switchboard Apparatus Inc 618 Lamont Rd, Elmhurst 60126 | (708) 450-0990 |
| Upower Supply Corp 949 N Larch Ave, Elmhurst 60126 | (630) 833-3754 |