B Phase CT on the Load Side , A & C Phase CT on the line side of bkr 2

[metta0810]

Dear all,

Does anyone know why A and C Phase CT located on the line side of the main breaker (Polarity towards the top of the breaker) and the B Phase CT located on the load side of the main breaker (polarity towards the bottom of the breaker)?

I've never seen this application before. Please let me know if anyone has any experiences with regards to this design.

Thanks

 

[oldfieldguy]

Not uncommon on low voltage breakers where conductor/bus spacing and other issues make conventional installation difficult.

old field guy

 

[waross]

As I visualize this, the polarity may be reversed on one CT. The reversal may be corrected in the secondary wiring.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Zogzog]

Maybe I am reading this wrong but polarity towards top or bottom should not matter, polarity facing to the front or rear of the breaker would be the concern.

 

[cranky108]

I'm not sure about low voltage stuff, but on higher voltage gear the polarty is away from the device (breaker).
If this is true on your gear, that would explain the reverse polarty.

 

[mg33]

Typical installation.
Probably to do with the phyiscal size of the CT

 

[ANGIBEW25]

Typically the CT's are mounted so that power flows into the polarity side first and towards the load.
On LVCB's that have smaller CT's they can be mounted on the Line Side in the same physical direction,and they will have the same polarity.
The reason that yours is different is due to the size of the CT's and the physical spacing between the Line Side Primary stabs.
If the physical spacing doesn't exist between the Line Side Bus Stabs then you can install the CT on the Load Side Bus Stabs, but you must reverse the CT'S polarity.
You can reverse the polarity by physical flipping the CT or by reversing the secondary wiring from the CT.
If you do not have the same polarity for all your CT'S the trip unit will trip the LVCB when you bring up load.
As pointed out by others this is a typical installation.