The Inertaire® System provides a regulated nitrogen gas supply to the gas space of power transformers. The user inserts a nitrogen gas cylinder into the Inertaire® compartment; makes the necessary gas connections and the Inertaire® system will maintain a positive pressure nitrogen gas blanket in the transformer’s gas space. The user can set the pressure range and the Inertaire® system will maintain the set pressure range by adding nitrogen or venting over pressure to the atmosphere. The Inertaire® System contains alarms to alert the user to over pressures or empty nitrogen bottles.