What type of branch-circuit disconnect requires GFI protection?

A disconnect rated at a minimum of 1000A requires Ground Fault Interrupter (GFI) protection to ensure safety in electrical installations. This requirement is rooted in the NEC (National Electrical Code) standards which aim to protect against electrical shock hazards, particularly in environments where moisture and water are present.

When a disconnect exceeds a certain amperage, such as 1000A, it becomes critical to implement protective measures, including GFI. This is especially true in commercial or industrial settings, where the risk of ground faults can lead to dangerous situations or equipment failure. GFI breakers function by monitoring the incoming and outgoing current; if there is a discrepancy, indicative of a ground fault, the GFI quickly cuts off power, thereby minimizing the risk of electrical shock.

In contrast, while disconnects rated above 800A might have specific safety requirements, the particular necessity for GFI protection becomes more imperative at the 1000A threshold. Additionally, it's important to note that not all outdoor circuits or all commercial disconnects necessarily require GFI protection unless they meet specific conditions as outlined in the NEC.