Graybar Chicago (Glendale Heights) is a full-service branch, with a counter, will call pickup and stocked inventory in an on-site warehouse. Graybar is a leading distributor of electrical supplies, communications, data network solutions, commercial and industrial lighting, and security equipment. Office hours: 7:00 am - 5:00 pm. Counter hours May - September: 6:00 am - 4:30 pm. Remainder of year: 6:30 am - 4:30 pm.