The conductivity of brass is only 28 percent of pure copper. Copper is the standard against which electrical materials are rated. The conductivity of brass varies by the amount of zinc in it when it is created; the lower the zinc content, the higher the electrical conductivity.
Brass is a substitutional alloy made of copper and zinc. It is often used when making electrical connections where strength is required. Other metals have a higher rating, but are not as desired. Silver has the highest percent at 105, followed by copper at 100. Gold has a conductivity percent of 70 percent. Steel has a low conductivity of 3 to 15 percent.