QO panel/ tandem breaker rated

[nizak]

Is there any way to tell if a panel is rated for tandem breaker use if the identification label is un readable? This is a QO single phase load center.I know that on Homeline for instance the bus makeup is physically different but the QO seems to have only one style.

 

[jim dungar]

Is there any way to tell if a panel is rated for tandem breaker use if the identification label is un readable? This is a QO single phase load center.I know that on Homeline for instance the bus makeup is physically different but the QO seems to have only one style.

There is a provision in the mounting rails for a 'hook' on the back of the QOT style breaker. Breakers without the mounting foot (i.e. the QO style tandem) are only listed for use in panels built before the 70's.