| Following the introduction of the I-16 singlephase and the DS-19 polyphase switchboard meters, a line of singlephase switchboard
meters was produced, and the table correlates the singlephase switchboard models to their polyphase versions. In 1955, the chrome
steel magnets were replaced with the smaller and more reliable Alnico V magnet assemblies. |
| Model | Polyphase equivalent |
| IS-8 (surface) | DS-19, DS-20 |
| IS-9 (flush-mount) | DS-34, DS-35 |
| IS-10 (flush-mount, draw-out) | DS-38, DS-39 |
| IS-11 (surface, draw-out) | DS-40, DS-41 |
| IS-12 (semi-flush or surface, draw-out) | DS-43, DS-44 |
|