What should be used if the expected fault current exceeds the rating of a jumper?

Using parallel cables with the correct derating factor is an effective approach when the expected fault current exceeds the rating of a jumper. This method allows for the distribution of electrical current across multiple cables, which helps to ensure that no individual cable is overloaded beyond its capacity. The inclusion of a derating factor is critical as it accounts for various environmental and installation conditions that can affect the performance of the cables, such as temperature and bundling of cables, ensuring safety and reliability in the electrical system.

In contrast, utilizing a single undersized cable would not be a safe option, as it would likely lead to overheating or potential failure under fault conditions. Simply replacing the jumper does not address the underlying issue of exceeding the fault current rating, which could result in the new jumper also being compromised. Enhancing insulation might improve electrical isolation but does not effectively manage the fault current risk inherent in the system. Therefore, using parallel cables with careful consideration of the derating factor provides a robust solution to handle high fault current situations.