In 1906, an electric light company in Pennsylvania had the option to purchase current from a power company at a lower rate than what it was then producing from a coal-fired plant. When the arrangement was made, a portion of the light plant was converted into a substation. The high voltage wall entrance was made without the need for new construction by installing pass-throughs in the existing wall. The center unit was made by Thomas and dates to 1906. The Ohio Brass pass-throughs use brass attachments and seem to be replacements, dating to the 1920s.