When primary injecting breakers I found that I need an aux power for a trip unit to turn on so that the LSI can be picked up. Otherwise, only the ground fault will alarm without any aux power connected. Is there a way to perform Pri inj without using aux power? I thought current would be enough to turn on any breaker. Any thoughts?
The trip unit should come on once a few hundred amps of current are applied to the breaker but your test will be off because of that delayed response. If the ground fault alarm is picking up you might need to series two poles before it will work.
It would also be helpful to tell us the Type of breaker and trip unit. Some manufacturer’s require 10% of all 3 phases or 30% of a single phase current to be pushed before the trip unit turns on. I’ve has a breaker trip on ground fault prior to meeting this requirement many times before.
You would still need the auxiliary power on some Digitrips to adjust the LSIG setpoints in order to test the breaker. In some cases like Eaton they cost an arm and a leg for a power supply.
Hey SecondGen I seen you had posted the 1150 and 520 trip unit curve excels for some reason when testguy added the new version it won’t allow me to download the excels, if by chance you still have them can you email them to me email@example.com. If you don’t that’s okay worth the try.
Can you give a link where the original file was posted?
This should be what you are looking for
Digitrip 520 Trip Curve Calculator.xls (39.5 KB)
Digitrip 1150 Trip Curve Calculator.xls (39 KB)
New Digitrip 1150 Trip Curve Calculator.xls (23.5 KB)
Dope!! Thank you i appreciate you taking the time in doing this! definitely a time saver!