This article breaks down the differences between IP54, IP55, IP65, IP66, and IP67, with insights into how each applies to real-world industry use. This article breaks down what each of these ratings means, compares their protective. . When you choose a diesel generator, its protection grade also is an important factor that you should consider. First Digit (0-6): Indicates protection against solid objects. An IP grade of at least IP55 ensures equipment stays safe from dust and water ingress.