NBC was one of the first tenants in the new RCA Building, and with 35 studios packed into the lower base of the building, it was also one of the largest tenants. RCA's chief engineer O. B. Hanson was faced with designing an area of the building that was large enough to host 35 studios with as few structural columns as possible. This was achieved by placing all the studios in the 16-story, windowless center part of the building, which would have otherwise been used as an unprofitable office space. Over of utility wires stretched through this part of the building, which was powered by direct current because the use of alternating current would cause transmissions to become spotty. Two floors were reserved for future TV studios, and five more stories were reserved for audience members and guests. During the building's early years, NBC housed both the Red Network and the Blue Network within 30 Rockefeller Plaza. The building also hosted daily tours of the NBC Studios. Studio 8H was the largest of the studios in the RCA Building, with the capacity to seat 1,400 guests.