Q: How do PESDs fit in with UL 508/NEC Tap Rules?

A: PESDs comply with the NEC 10ft Feeder Tap Rule as they have a built-in high impedance between the feeder line connecting leads and the circuitry.

Per UL 508A, there are no exceptions that allow for the Voltage Indicators to be used in lengths longer than 12” without overcurrent protection. One option is to use sufficient wire per the tap rule up to a terminal block that is within 12” of the Voltage Indicator. The final option is to use our R-3F2 series voltage indicators. These indicators use optical light cable to transmit the LED voltage indication so that you can mount the power unit within 12” of the disconnect and the fibers can be in lengths of 12 – 72”.

Please review the Overcurrent Protection Datasheet for more information. The last page goes into the options to conform to the UL 508A 12” tap rule.