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Video: QO, QOB and HOM Arc Fault (CAFI) and Dual Function (DF) circuit breaker troubleshooting tips. Helpful documentation on why they trip. Fault Indication Procedure - Time Saver Diagnostics

Product Line:
QO, QOB and Homeline Arc Fault (CAFI) and Dual Function (DF) circuit breakers.  White and Purple test buttons.
Does not apply to the older AFI breakers with Blue or Green test buttons.
Does not apply to GFI, EPD or EPE breakers with Yellow or Black test buttons.

Environment:
"Time Saver" diagnostic feature on products with date codes 1130 and higher.
Data Bulletin 0760DB0204 ``Determining the Cause of AFCI Tripping``
48840-248-01  QO and QOB combination arc fault breaker instructions that come with the breaker, includes the CAFI Fault Indication Procedure
48840-249-01  HOM combination arc fault breaker instructions that come with the breaker, includes the CAFI Fault Indication Procedure
HRB86114  Dual Function HOM instructions
HRB73152  Dual Function QO instructions

Cause:
Providing protection. Unwanted tripping.  Need to determine why the breaker is tripping.

Resolution:
NOTE: Read all cautions and warnings in the above literature, and on the product.  Electrical work and troubleshooting should be done by an authorized person.

There are four main points outlined below:
Part I. CAFI and DF Fault Indication Procedure - Time Saver Diagnostics
Part II. The two most common reasons for unwanted tripping:  Incorrect installation and Grounded Neutral Trouble Shooting
Part III. Arc Fault Trip
Part IV. 2 pole CAFI (Combination Arc Fault Breaker)

Part I. CAFI and DF Fault Indication Procedure - Time Saver Diagnostics
  1. Place circuit breaker in O/OFF position.
  2. Firmly press and continue holding the ‘TEST’ button through Step 4.
  3. Move handle to I/ON position.
  4. Circuit breaker should trip at one of the following times.

Trips Instantly (less than 1 second) Fault to Ground Includes:
  • Arcing to ground
  • Shared neutral
  • Grounded neutral
  • Ground fault
Trips at 2.0 seconds Arc Fault Includes:
  • Parallel arc fault
  • Series arc fault
Trips at 5.0 seconds Procedure Complete Includes:
  • No Fault
  • Thermal overload
  • Short circuit
To reset Fault Indication:
  1. Perform the CAFI Fault Indication Procedure a total of 6 times
  2. Verify by performing CAFI Fault Indication Procedure with a trip at 5.0 seconds (Procedure Complete) result.
An automatic reset of Fault Indication will occur if the CAFI circuit breaker has been powered continuously for 27 days.

The below short video (1:30, with sound) shows the Time Saver Diagnostics procedure.
The video specifically discusses CAFI breakers, but this also applies to DF breakers.


Part II.  The two most common reasons for unwanted tripping:  Incorrect installation and Grounded Neutral Trouble Shooting:
  1. Turn panel power off.  Remove the load wires from the breaker (black and white wires going to the outlets), so that you only have the breaker in the panel (if the breaker has a white coiled wire, leave it attached to the panel neutral bar). Turn panel power back on. At this point the breaker should turn on and trip with the test button. If not, replace the breaker. If it works properly here, go to step 2.
  2. Turn panel power off.  Re-install the load wires. Black and white wires go the terminals on the breaker (Pigtail version and Plug on Neutral version must have white load neutral wire attached to the breaker). White coiled wire goes to the neutral bar.  Turn panel power on.  Try plugging in something and applying a load. If it does not trip then maybe you had the breaker installed incorrectly. If the breaker trips, no matter what you turn on or plug in, then you most likely have a grounded neutral (bare ground wire touching neutral) in your load wires some where, which you can verify in the next step.
  3. Turn panel power off.  Remove the white load neutral wire from the breaker (not the white coiled wire). Check continuity between the removed white wire and the ground/neutral bar. If you have continuity then you have a grounded neutral wire. Probably a bare ground wire touching the neutral screw in a junction box or outlet.
  4. If you have a grounded neutral, leave the white load wire disconnected from breaker and go to the first junction and disconnect the neutrals and grounds and measure resistance across neutral and ground and see what side of the junction the problem is on. Note: the problem is most likely in the junction itself. If the bare ground is touching the neutral wire or screw check that first before removing any wires. Then proceed to the next junction until you find the problem.

​Part III.  For a List of Causes of CAFI Tripping, please read Data Bulletin 0760DB0204 ``Determining the Cause of AFCI Tripping``
Tripping due to an arc fault appears to be instantaneous as do those from a short circuit trip and a ground-fault trip (typically in less than one second). The only type of tripping that responds relatively slowly is tripping due to overloads
(seconds or tens of seconds). If an arc-fault is suspected, the first diagnostic step should be to determine if the arc fault is in the appliance, its power cord, or if it is in the permanent wiring.
  • Checking Appliances: To narrow the problem down to the appliance or its power cord, first, isolate all appliances by unplugging them. If the AFCI does NOT trip when it is re-closed, then the problem is likely an arc fault in either the appliance or its power cord. A series arc fault will not be detected until a load is connected and energized. The faulty appliance can be identified by connecting one load at a time until the AFCI trips again. Check the last load connected for arcing, insulation problems, shorted or pinched wires, etc.
  • Checking permanent Wiring: If the AFCI continues to trip after all of the appliances are unplugged, then a problem in the permanent circuit or a problem with the AFCI can be considered. First, check for arcing, insulation problems, and shorted or pinched wires at outlets, switches, and junction boxes.


Part IV.  2 pole CAFI (Combination Arc Fault Breaker)
The 2 pole CAFI is only for a 120/240Vac system, not designed for the 120/208Vac system.  Will not function on 120/208Vac system.
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