In most cases LSIG is an option that makes it posible to coordinate breakers.
In most cases LSIG is an option that makes it posible to coordinate breakers.
LSIG, Long time, Short time, Instantaneous, and ground fault are options that are available in breakers that electronic trip units. Breaker frames that have interchangeable trip units commonly start out with 250a frames, 400a, 600, 800, 1200a etc. A 250a frame can have a trip unit that is available down to 75a-250a, the 400a (70-400a), 600a (125-600), 800 (400-800), 1200 (400-1200).
LIG is fairly common where you would have a rating plug which rated the breaker a specific amp rating, and adjustable magnetic (I), and ground fault pick-up (G) all which should be self explanatory. There is also an LSI option.
The (s) for short time delay really doesn't bring much to the party unless there is a party, that is if it is related to with breakers. The adjustable short-time allows the breaker to be coordinated with another breaker or breakers such that the breaker closest to the even is given the opportunity to trip and clear first.
The 'I', is for adjustable short time pick up and delay with a pick up of 200-800% as an example. After pick up then the delay can be set on some breakers up to 100ms while on larger breakers 100-500ms. Between the two adjustments it provides you with the capability to coordinate breakers.
And likewise with ground fault, on smaller breakers the GF pick up range available can vary while on larger frames it can be from 25-100% of the frame rating not to exceed 1200a. Then you have the delay which often is inst. to 500ms on the smaller frame to 100-500ms with larger frames. Just like the (s) you are given the ability to coordinate.
Please note that the time delay is limited to 500ms because of the breaker's withstand capablity
These options are expensive and should not be specified unless you have a reason. Having these options doesn't make a breaker better.