- Which section of the code would I use to size the feeder to a switchboard which feeds more than one VFD? Would it be 430.122? 125% of largest VFD plus rated input of the other VFDs?
- Assuming that when the switchboard loses power and upon regaining power, all VFDs startup simultaneously, would the feeder to the switchboard HAVE to be sized as 125% of total sum of all VFD rated inputs? If so, which code section applies?
Variable Frequency Drive Feeder
- Thread starter vince66
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
430.122 applies to the BRANCH circuit going to the VFD. In fact most of 430 is specific to motor Branch circuits (unless the paragraph specifically references multiple motor connections). A Branch circuit is defined as the last circuit going to a load. Feeding power to a switchboard is not a branch circuit, it's going to be either a Feeder circuit from something above it like another Service Switchboard, or its a new Service itself. Each of those have other references associated with them in the code.
The specific words used in the code are important to understand. All of these terms are defined in Article 100.
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