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Pressing the purple test button on the QO or HOM DF breaker does not trip the breaker. Power is from a generator, off-grid.

Issue:
Pressing the purple test button on the QO or HOM Dual Function breaker does not trip the breaker, even when the Load H and Load N wires have been removed from the breaker. The power supply is only a generator, with no connection to utility company power (off-grid).

Product Line:
Circuit Breakers

Environment:
Applies to QO and HOM circuit breakers with DF suffix (purple test button)
Applies to situations in which the power supply is a generator (off grid, no utility power)

Resolution:
QO and HOM DF breakers are designed and tested to be used on a system that produces good quality power, with no significant distortion in the sine wave (figure 1).

Figure 1 - Good Power Quality

If QO and HOM DF breakers are used on a system that produces poor or bad power quality (figure 2), the distortion in the sine wave can affect the electronics in the breaker, leading to a situation in which pressing the test button will not trip the breaker.

Figure 2 - Poor Power Quality

When a generator/inverter is used as the power supply feeding QO-DF or HOM-DF breakers, it is important that the generator/inverter produce good power quality. These types of generators/inverters are sometimes referred to as producing power with a "clean sine wave", "pure sine wave" or "true sine wave". To avoid the issue above in which the test button does not trip the breaker, only use generators that produce good power quality.
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