Three ground conductors spaced symmetrically with the three phase conductors develop much lower levels of common-mode noise currents in the inverter's PE bus. NEC is in the works. A metrication proposal is open for comment. The NEC Metrication Task Group has developed proposed guidelines for the 2002 NEC code-making panels. Your comments are invited.
All proposals receive responses.
To Include Metric PCU Archive Tech Home . Express all units in SI units first followed by the equivalent inch-pound units in parenthesis. The Task Group will not require conversion of any industry unless the manufacturers support the action. We have proposed including a column in Chapter 9, Table 8 to list the equivalent conductor area expressed in mm2. Box dimensions and metal thicknesses will be soft converted.