This standard@ for both detachable and bottom-connected watthour meters@ covers class designations@ voltage and frequency ratings@ test-current values@ internal wiring arrangements@ pertinent dimensions@ rotor markings@ register requirements@ and other general specifications. The terminal arrangements and mounting dimensions covered by this standard are essentially those adopted by the watthour meter industry during the period 1928 to 1936. This standard also applies to combination devices utilizing the essential elements of watthour meters insofar as their application is practicable.