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How does a QO-GFI, HOM-GFI or CHOM-GFI breaker work?

Issue:
How does a QO-GFI, HOM-GFI or CHOM-GFI breaker work?

Product Line:
QO, HOM, CHOM MCB's

Environment:
MCB' Sold in North America

Cause:
How does the breaker know if there is a ground fault.

Resolution:
The GFCI sensor in a QWIK-GARD circuit breaker continuously monitors the current flow in the ungrounded ``hot`` load conductors and the neutral conductor. The sensor compares the current flow in all directions. If the current flowing back to the source is less than the current flowing out to the load, a ground fault exists. When the difference in current flow exceeds 6 milliamperes, the sensor sends a signal to the solid state circuitry which activates the ground-trip solenoid mechanism and trips the circuit breaker. The trip will be indicated by the operating handle moving to the center tripped position on QO, HOM and CHOM. In addition on QO breakers the trip will be indicated by the VISI-TRIP indicator.
On 2P 15A to 50A the GFI breaker will work with or without a load neutral wire. However, if there is no load neutral wire the breaker neutral (white curly wire) must still be connected to the panel neutral.
On 2P 60A and all 3P (QO only) there is no load neutral wire connection on the breaker. Again the breaker neutral (white curly wire) must be connected to the panel neutral. The sensor compares the current flow in both directions and trips the breaker when more than a 6mA inbalance occurs.
See Instruction Bulletins:
1P QO-GFI: 48840-088-01 HOM/CHOM-GFI: 48840-090-01
2P QO-GFI: 48840-435-03 HOM/CHOM-GFI: 48840-058-03
3P QO-GFI: 48840-260-01



CTA-ID : 2026092
FA115047  |  12-Mar-2015  | Application
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