AC Voltage Drop

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The National Electric Code (NEC) does not regulate voltage drop through code requirements. The code does provide recommendations for minimum operating voltages to prevent inefficient operation or malfunction of electrical equipment through informational notes. The informational notes specify a maximum voltage drop of 3% for branch circuits and 5% for feeder circuits. In support of this calculation the NEC does publish Table 9 with typical resistance and reactance values for 600 V cable.

The National Electric Code (NEC) specifies the minimum size for cable tray systems which includes ladder, ventilated trough, ventilated channel, solid bottom and other similar structures. It’s important to note that cable trays are mechanical support systems and not raceways. Raceways are included in another section of the code.

Proper cable tray sizing is complicated and often existing cable trays are overloaded per the code. If you have questions or would like some engineering assistance to properly size your cable tray installation please contact us.

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