W. Va. Code § 3-4A-10a: Proportional distribution of vote-recording devices.

Where vote-recording devices are used, the county commission of each county shall, upon the close of registration, review the total number of active registered voters and the number of registered voters of each party in each precinct. Prior to each election, the commission shall determine the number of voting devices needed to accommodate voters without long delays and shall assign an appropriate number to each precinct. For the purposes of the primary election, the commission shall assign the number of vote recording devices in each precinct to be prepared for each party based as nearly as practicable on the proportion of registered voters of each party to the total: Provided, That a minimum of two vote-recording devices be provided.