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What does the "CTL" shown on the load center labeling mean for a QO or Homeline load centers?

Product Design features

Product line:
QO and Homeline load centers

Circuit Limiting


The "CTL", means "Circuit Tandem Limiting". It is a marking required by UL67 on lighting and appliance panelboards. Paragraph 30.8.3 of UL67 states  "A Class CTL panelboard designed to permit installation of certain units in specified positions only shall be marked: a) To clearly indicate those positions, and b) With the maximum number of poles that the panelboard is intended to accommodate."
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