WebCoordination Ratio All fuses to BS 88 Parts 2 and 6 will give a coordination ratio of 2:1; and for most practical situations a ratio of 1.6:1 (two steps in the R10 series). Example: an upstream fuse rated at 160A will coordinate with a downstream fuse rated at 100A. Current and Energy Limitation The range of fuses have pre-arcing I2t values ... WebAug 11, 2024 · There are two ways to choose a fuse size: Use the manufacturer’s recommended fuse size; Calculate the fuse size yourself; Let’s look at an example for …
Designing for selective coordination Consulting
WebJun 18, 2024 · Fuse melting and clearing I 2 t values must be compared to assess selectivity for fuses operating in their current-limiting range. The total I 2 t of the … WebAug 4, 2024 · For selectivity between fuses, the rule of thumb is that an upstream fuse will discriminate with a downstream fuse of half its rating. For selectivity between circuit- … great-west mod aggr profile fund inv
How to Calculate Fuse Size Hunker
WebTo verify selective coordination, go no further than the Fuse Selectivity Ratio Guide in the Fuse Selective Coordination section in this book. The Low-Peak fuses just require a 2:1 amp rating ratio to assure selective coordination. In this example, there is a 4:1 ratio between the main fuse (1600A) and the first level feeder fuse (400A) and a 2 ... WebOct 1, 2009 · Because of this capability, fuse manufacturers are able to publish a set of “fuse coordination ratios,” which will guarantee selective coordination at any fault level. The fuse ratios are anywhere between 1.5 and 8-to-1, depending upon the type of fuses used, with type RK5 time-delay fuses having the lowest ratio when used upstream, and the ... WebInterest in complete overcurrent device selectivity has increased due to the addition of selectivity requirements to articles 700, 701, and 708 of the National Electrical Code … great west mid cap value inv