Sparkyak:
The 'math' amperage /voltage is just 'math'. Real world the strip heaters could be drawing less amperage, high resistance at connections (buss to brkr stabs) may result in a 'lower' amp draw.
I have seen quite a few CBs over the years that 'held' at the rating, or at a small percentage above the rating. A steady resistave load that has no 'peaks' is what I'm describing. A sudden 'line-line', or grd short would cause the CB to trip.
If this is a famous 'old' brand .....no issues with tripping at all.
