Circuit Breakers and Supplemental Protection Devices

Can you use a 3 pole L9 breaker on a 1 or 2 pole load?
Can you use a 3 pole L8 breaker on a 1 or 2 pole load?
Can I use just 2 of 3 poles from L9-10/3/C (2 phases from 3 phase lines) 1st and second pole?

What is the difference between Auxiliary Contact L9-AMRA3 and a Signal contact block L9-AMRS3?

The increased use of high efficieny motors requires a closer look at specifications when applied to circuit protection methods. Not considering all of the factors can lead to specification errors and nuisance tripping or worse.

Which protection devices are best for your application? Where do they fit in the schematic of your panel?

How to design for and apply supplementary protectors in accordance with UL & NEC guidelines.

Do the components in a control circuit have a short circuit current rating? UL and NEC rules define which components in a control panel require a short circuit current rating.

Indicators on fuse holders and terminals form a parallel path with the fuse they are monitoring. Dual LED indicators may not necessarily utilize both LEDs to indicate a blown fuse.

Unlike the fuse box in most residential power centers, industrial circuit protection can rarely be reused after a short-circuit. Some products are specifically tested by UL to withstand a short circuit.

A variety of products can be used to perform as a circuit breaker for motor and non-motor loads, but some perform better than others.