- Square Dâ„¢ is the industry leader in circuit protection with a long-standing reputation for quality and reliability. Square Dâ„¢ offers Homelineâ„¢ a wide range of circuit breakers to meet all National Electric Code requirements and provide superior electrical safety, including: Dual Function, 1 and 2-Pole Combination Arc-Fault Circuit Interrupters (CAFIs) and Arc-D-Tect CAFI Circuit Breakers. Homelineâ„¢ Load Centers accept Plug-On Neutral, pigtail, full-size and tandem circuit breakers on every space.