Federal Pacific NA35 Miniature Circuit Breaker

The NA35 is a 1-inch wide thick breaker, whereas the NC series are 1/2-inch wide thin breakers. While both utilize the Stab-Lok connection, replacing an NC breaker with an NA breaker requires a full 1-inch space in the panel. If the panel is fully populated with thin breakers, the NA35 will not fit in a half-space slot.

Connecticut Electric manufactures aftermarket replacement breakers for Federal Pacific Stab-Lok panels under the UBI brand. These UBI replacements are ETL listed and classified to UL 489 standards for use in original FPE load centers.

Original FPE Stab-Lok panels have a documented history of failing to trip during overcurrent or short-circuit events. When replacing a faulty breaker with an NA35, electricians should inspect the busbar for pitting or arc damage, which is common in these panels. Many professionals advise a complete panel upgrade to meet current safety codes.

The NA35 utilizes the proprietary Federal Pacific Stab-Lok connection. Instead of clipping onto a mounting rail and snapping onto a bus tab like modern breakers, the Stab-Lok design uses a slotted busbar where the breaker contact prong stabs directly into the bus slot.

The LI designation stands for Long-Time and Instantaneous trip functions. Long-Time provides thermal overload protection for sustained overcurrents, while the Instantaneous magnetic function trips the breaker immediately during a short circuit. The NA35 has fixed, non-adjustable trip settings.

The NA35 lugs accept 14 AWG to 2 AWG wire. When wiring a 35A circuit, ensure the conductor is appropriately sized for the 35-amp load and temperature rating, typically requiring 8 AWG copper wire depending on the insulation type and installation conditions.