Breaker reset on modular power unit

[BillP]

This question was originally posted by James on APC forums on 3/8/2015

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I have breakers that have 3 poles connected with 'handle ties'.  From what i gathered, this is safety mechanism for 3 wires sharing same neutral. No issue with that, but when a single leg trips due to device issue that backfeeds to the breaker, my question is, can I remove the handle tie to reset only that leg?  It appears the handle tie is removable and used for codes where needed.  I dont think it would be any code violation to remove it to reset the breaker, but I can not find any information on this.  Has anyone here had this experience?  I really do not want to reset all 3 phases as other devices do not need the added disruption of power off, then on.

this is on pdpm277 with breaker pdm3520, 3 phase, 5 wire breaker.

[BillP · Accepted solution]

This reply was originally posted by Angela on APC forums on 3/9/2015

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Hello,

I checked with our 3 phase power team for help on this. Here is what they told me:

The installation of the handle ties are based on the load type (single or 3 phase & voltage).
This is regulated by the NEC.

IE: If the load is 120V single phase, then no handle tie is required since only a single pole breaker is needed for this type of load.
If load is 208V or 277V single phase, then a 2 pole breaker is needed and therefore on a 3 pole breaker module, you would need a handle tie on 2 of the 3 breakers.
If load is 208V 3 phase, then a handle tie would be needed across all 3 breakers.

The NEC Code requires that a circuit breaker providing power to any given load needs to open all current carrying conductors for that load at the same time during a fault.

So, if you are resetting a single phase load ( 120V or 277 ) then yes, you can reset the individual breaker, otherwise, no.