A foam sealing block is provided for sealing a cable channel by which one or more cables traverse into an air-cooled compartment. The foam sealing block may folded around the cables and positioned within the cable channel. The insertion of the folded foam sealing block prevents the transfer of air from the air-cooled compartment via the cable channel, while still allowing the cables to traverse the cable channel. The top surface of the foam sealing block may formed from offset rows of protrusions, such as hemispherical shaped protrusions. The dimensions and shape of the protrusions may be selected based on the physical characteristics of the cables traversing the cable channel. The bottom surface of the foam sealing block may be formed from a perforated, rigid bracket that allows the foam sealing block to fit securely within the cable channel.