UL 1077 DIN Rail Supplementary Protection
Miniature Circuit Breakers
Miniature Circuit Breakers (MCBs) are a vital element for circuit protection in f electrical systems. They protect circuits from overloads and short circuits, preventing damage to equipment, and potentially dangerous electrical fires or injury. Breakers are automatic switches that interrupt the flow of electricity by tripping quickly and shutting off power to the affected circuit before any damage from an overload or short circuit occurs. Noark’s MCBs offer excellent quality in a compact size and are backed with our standard 5-year warranty which makes them ideal for use in a wide range of applications.
The key to understanding UL 1077 supplementary protection and UL 489 branch protection requirements is to first understand how to identify the products, the applications they can be used for and importance of selecting the correct device in compliance with UL standards and NEC Codes.
• A UL 489 device can be used as branch circuit protection or supplementary protection.
• UL 1077 devices are Used for overcurrent protection within appliances or electrical equipment, where branch circuit protection is already
provided or not required.
UL 489 Circuit Breakers and Branch Circuit Overcurrent Devices
National Electrical Code (NEC) defines a branch circuit as the circuit conductors between the final overcurrent device protecting the circuit and the outlets. UL 489 opens automatically on overload and short circuit. It also protects wire and cable against overload and short circuit. UL 489 circuit breaker used for branch circuit protection.
UL 489 Applications:
• Receptacles and branch lighting
• Control Panels
• Load circuits leaving the equipment (external)
• Uninterruptible power supply (UPS)
• Relays
• Heating, ventilation, air conditioning and refrigeration equipment (HVAC/R)
• Variable frequency drives (VFD)
Features:
• DIN rail mountable
• Stand alone Branch Circuit Protection
• External handle mechanisms available
• Field mounted accessories
• Various levels of protection (curves)
UL 1077 Supplementary Protectors & Overcurrent Devices
UL 1077 Supplementary Protectors & Overcurrent Devices UL 1077 Supplementary Protector is a manually re-settable device designed to open the circuit automatically on a predetermined value of time versus current or voltage within an appliance or other electrical equipment. A supplementary protective device is intended to provide limited overcurrent protection for specific applications and utilization equipment such as cabinet lighting and appliances.
Example: only use UL 1077 to protect circuits inside the equipment that do not feed circuits that exit the equipment.
UL 1077 Applications:
• Cabinet Lighting
• Appliances
• Control Power Transformers
• Relays
• Control Circuits
Features:
• DIN rail mountable
• Field mounted accessories
• Various levels of protection (curves)