Siemens LI and LSI trip units swap.

82angelfan

Member
Location
Hesperia, Ca
Can I swap trip units?

Looking for some information. I have installed Siemens FG250A frames in hospital ER existing main distribution boards. Breakers were provided by owner. The trip units in the breakers are LSI model 555. The one-line and the coordinated study show LI model 555 trip units. One is 100amps the other is 150amps. The issue at hand is that the dial settings do not match the coordinated study and sense this is an OSHPD job we cannot get the TIO signed off.

Is it possible to change the trip units without removing the breaker from the gear. I'm trying to avoid multiple shut downs.
 

Attachments

  • E-501_ ONE-LINE Rev.8 markup_Breaker Submittal Links 15.pdf
    219.6 KB · Views: 2
  • E-501_ ONE-LINE Rev.8 markup_Breaker Submittal Links 16.pdf
    221.5 KB · Views: 1
  • E-501_ ONE-LINE Rev.8 markup_Breaker Submittal Links 17.pdf
    186.6 KB · Views: 1
  • 2505 19-15.3 B-E-10 APPROVED Coordination Study Factory SUBMITTED FOR RECORD 29.pdf
    113.9 KB · Views: 1

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I am not 100% sure but I don't think the trip units can be changed out at all in the electronic trip style breakers.

In any case, you would have to shut the power off to replace the trip units if it was replaceable so I don't see what you would gain
 

ron

Senior Member
The Siemens website indicates
  • Wide range of field installable internal and external accessories
It would still need to be turned off to replace the trip unit.

 
Top