These standards specifically cover the following types of bushings: ( o ) Outdoor bushings for large apparatus. ( 6 ) Cover type bushings for small apparatus. ( c ) Indoor bushings for all types of apparatus except dry type instrument transformers, air-blast transformers, dry type regulators, and circuit breakers rated below 5,000 volts, and non-oil tight oil circuit breakers rated 50,000 kva or less. These standards are not intended to apply to wall bushings, cable potherads, nor insulators for back connected disconnecting switches, although many of the principles may be applicable. The bushing requirements as specified in these standards apply to bushings when mounted for testing in accordance with specified arrangements as given in the Test Code (Appendix I ) . Requirements when installed in apparatus should be covered by standards for such apparatus.