Thermal magnetic trip unit

Location
Wyoming
Occupation
Electrician
I have an eaton 400a 208v main breaker in a panel. The panel will only be used for running motel ptac units. What should the 3 dials be set to on the bottom of the breaker? The model number is kt3400t.

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jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
The breaker should have come set to its nominal full rated value. Are your adjustments for the short circuit trip?

When in doubt leave them set to minimum until you get more information.
 
Last edited:

ron

Senior Member
The magnetic trip is adjustable from 5–10 times continuous ampere rating.

If you don't have a coordination study to tell you otherwise, typically it gets left at 5X
 
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