A process variable transmitter for use in an industrial process includes a housing having a cavity formed therein. The housing has a barrier which divides the cavity into first and second cavities. Preferably, measurement circuitry in the first cavity is configured to measure a process variable of the industrial process. A terminal block assembly is positioned in the second cavity. The terminal block assembly forms a seal with the housing thereby forming a third cavity between the barrier and a circuit board of the terminal block assembly.