Abstract: A self-contained fire protection system can be supplied in kit form and is specifically adapted for installation by a novice in prefabricated or site built housing, such as, a mobile home, travel trailer or like building structure. The system comprises an inlet delivery line which can be suspended beneath the floor of the mobile home and attached to a source of water under pressure with one or more risers extending upwardly from the delivery line through the floor into the interior of the mobile home, and upper branch lines containing automatic sprinkler heads are arranged in series in each branch line and can be attached directly to the risers and inlet line as well. The delivery line has a dual check valve and water flow indicator or switch, the latter being responsive to opening of any one or more of the sprinkler heads to activate a shunt trip breaker circuit so as to automatically interrupt electrical service to the home including the gas line into the home while activating an alarm circuit.