We install rodent guard mesh on all our residential rooftop installations. The Canadian Electrical Code requires it in most instances.
Rule 64-210 5):
Where the dc arc-fault protection referred to in Rule 64-216 is not located at the module, photovoltaic source circuit insulated conductors and cables installed on or above a building and installed in accordance with Subrules 1), 2), and 3) shall be provided with mechanical protection in the form of an enclosed raceway or other acceptable material to protect against damage from
rodents.
Where the dc arc-fault protection referred to in Rule 64-216 is not located at the module, photovoltaic source circuit insulated conductors and cables installed on or above a building and installed in accordance with Subrules 1), 2), and 3) shall be provided with mechanical protection in the form of an enclosed raceway or other acceptable material to protect against damage from rodents.