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Short Circuit Study: The short circuit study can lesson the risk your company faces and help avoid catastrophic losses. It's about safety & reliability.Far too often, the electrical system goes through changes without serious consideration of short circuit levels, and equipment ratings. Even new buildings and installations are not immune. The results can be expensive at best, disastrous at worst. A severe fault (short circuit) in your system can have catastrophic consequences.The short circuit study is fundamental. Fault levels vary from system to system, and location to location. This study calculates the maximum available short circuit current at various points throughout the system. Calculated values are then used to evaluate the application of protective devices, and to develop circuit breaker trip settings (see Protection/Coordination Study). The Short Circuit Study:
It's a matter of "when" a fault will occur not if!
What are short circuit ratings? It's not uncommon for plant engineers to be unfamiliar, or downright confused, when it comes to understanding short circuit ratings. If you find yourself in this category, here are some things to consider: Circuit breakers and fuses come with an overcurrent rating (or size), and a short circuit interrupting rating. The overcurrent rating specifies the amount of electrical current the device should tolerate without the fuse blowing, or circuit breaker tripping. The short circuit rating is the maximum electrical current the device can tolerate before it fails. Consider for example, a 100 amp circuit breaker. At some value of current exceeding 100 amps, you'd expect the breaker to trip . If 150 amps passes through the breaker for a certain period of time, it should trip. But what happens if 20,000 amps flows through the device? Will the breaker trip, or explode? The answer depends largely on the manufacturer's short circuit interrupting rating for that device. If the short circuit rating was 30kA it should trip, while a 14kA rated breaker would very likely explode. The short circuit study examines this for you. Fault levels are calculated at points throughout the system, and compared to the short circuit interrupting ratings of the devices used at each location.
This analysis is included as a standard part of the Electrical System Base Study. |
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Send email: info @ midwest-ps.com
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