CA DOJ regulatory standards require a gun safe to meet either:
All of the following requirements:
Shall be able to fully contain firearms and provide for their secure storage;
Shall have a locking system consisting of at minimum a mechanical or electronic combination lock. The mechanical or electronic combination lock utilized by the safe shall have at least 10,000 possible combinations consisting of a minimum three numbers, letters, or symbols. The lock shall be protected by a case-hardened (Rc 60+) drill-resistant steel plate, or drill-resistant material of equivalent strength;
Boltwork shall consist of a minimum of three steel locking bolts of at least ½ inch thickness that intrude from the door of the safe into the body of the safe or from the body of the safe into the door of the safe, which are operated by a separate handle and secured by the lock;
Shall be capable of repeated use. The exterior walls shall be constructed of a minimum 12-gauge thick steel for a single-walled safe, or the sum of the steel walls shall add up to at least .100 inches for safes with two walls. Doors shall be constructed of a minimum of two layers of 12-gauge steel, or one layer of 7-gauge steel compound construction;
Door hinges shall be protected to prevent the removal of the door. Protective features include, but are not limited to: hinges not exposed to the outside, interlocking door designs, dead bars, jeweler’s lugs and active or inactive locking bolts.
or
All of the following requirements:
Is listed as an Underwriters Laboratories Residential Security Container;
Is able to fully contain firearms;
Provides for the secure storage of firearms.