Which of the following should vent connectors for residential appliances not be covered with?

Vent connectors for residential appliances should not be covered with insulation due to safety concerns related to heat exposure and potential fire hazards. Insulation can trap heat that is produced by the exhaust gases, which could lead to a temperature increase that poses a risk of ignition. Vent connectors are designed to allow exhaust gases to exit the home safely, and covering them with insulation can impede this function, leading to dangerous situations.

In contrast, materials like PVC, sheetrock, and wood are not typically in direct contact with vent connectors and would not pose the same risk as insulation does when it comes to heat buildup. Vent connectors need to remain accessible and enable proper ventilation, so ensuring they are not covered with materials that could create a hazard is critical for maintaining a safe environment in residential settings.