W DOC AIRBUS | TSM A320F

Failure of the External Power

TASK 24-41-00-810-812-A
Failure of the External Power

1. Possible Causes
  • Ground Power Unit
  • C/B-GND/PWR/PROT [2XG]
  • wiring
  • feeders
  • GAPCU [24XG]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 24-00-00-810-803-A
Circuit Breaker Tripped and/or C/B TRIPPED Warning
AMM 24-41-00-861-002
Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002
De-energize the Aircraft Electrical Circuits Supplied from the External Power
ASM 244101
AMM 24-41-34-000-001
Removal of the Ground Power Control Unit (GPCU)
AMM 24-41-34-400-001
Installation of the Ground Power Control Unit (GPCU)
3. Fault Confirmation
Subtask 24-41-00-740-052-A ** ON A/C NOT FOR ALL
A. If the external power source is connected to the aircraft electrical circuits while a different source supplies the aircraft electrical circuits (IDG, APU, batteries):
  • on the ELEC panel 35VU, release, push and release again the ELEC/EXT PWR pushbutton switch (10XG) to do a reset of the GAPCU protection function. Then close the interlock on the Ground Power Unit (GPU).
   (1) If on the EXT PWR panel 108VU, the EXT PWR/AVAIL caution light (9XG) comes on and if on the ELEC panel 35VU, the AVAIL legend of the ELEC/EXT PWR pushbutton switch (10XG) comes on:
  • stop the trouble shooting.
   (2) If on the EXT PWR panel 108VU, the EXT PWR/AVAIL caution light (9XG) stays off and if on the ELEC panel 35VU, the AVAIL legend of the ELEC/EXT PWR pushbutton switch (10XG) stays off:
  • do the trouble shooting given in Para. 4.B.
Subtask 24-41-00-740-062-A ** ON A/C NOT FOR ALL
B. If the external power source is connected to the aircraft electrical circuits with no other source(s) connected (IDG, APU, batteries):
  • on the ELEC panel 35VU, push the BAT 1 and BAT 2 pushbutton switches (7PB1 and 7PB2) (on the MCDU menu page, make sure that the CFDS indication comes into view).
  • on the ELEC panel 35VU, release, push and release again the ELEC/EXT PWR pushbutton switch (10XG) to do a reset of the GAPCU protection function. Then close the interlock on the Ground Power Unit (GPU).
   (1) If on the EXT PWR panel 108VU, the EXT PWR/AVAIL caution light (9XG) comes on and if on the ELEC panel 35VU, the AVAIL legend of the ELEC/EXT PWR pushbutton switch (10XG) comes on:
  • stop the trouble shooting.
   (2) If on the EXT PWR panel 108VU, the EXT PWR/AVAIL caution light (9XG) stays off and if on the ELEC panel 35VU, the AVAIL legend of the ELEC/EXT PWR pushbutton switch (10XG) stays off:
  • do the trouble shooting given in Para. 4B.
4. Fault Isolation
Subtask 24-41-00-865-051-A ** ON A/C NOT FOR ALL
A. Table of the circuit breakers used in this procedure:
PANELDESIGNATIONFINLOCATION
** ON A/C NOT FOR ALL
123VUGND/PWR/PROT2XGAB07
Subtask 24-41-00-810-060-A ** ON A/C NOT FOR ALL
B. If the test confirms the fault:
  • On the AC power center panel 123VU, do a check of the status of the GND/PWR/PROT circuit breaker (2XG).
  • Replace the Ground Power Unit .
  • On the ELEC panel 35VU, release, push and release again the ELEC/EXT PWR pushbutton switch (10XG) to do a reset of the GAPCU protection function. Then close the interlock on the GPU.
   (1) If the circuit breaker (2XG) is open:
     (a) If the fault continues:
  • Replace the C/B-GND/PWR/PROT [2XG] .
   (2) If the circuit breaker (2XG) is closed:
  • Do a check of the Point-Of-Regulation (POR) sense wiring ASM 244101 for an open or a short circuit between:
    . pin A/J of the EPC (3XG) and pin B/15J of the GAPCU
    . pin A/H of the EPC and pin B/14J of the GAPCU
    . pin A/G of the EPC and pin B/13J of the GAPCU.
     (a) If the wiring is not correct:
  • Repair or replace as necessary.
     (b) If the wiring is correct:
  • Do a check of the external power feeders ASM 244101 for an open circuit, a short circuit or a short to airframe between:
    . pin A of the external power receptacle (20XG) and pin A/K of the EPC (3XG)
    . pin B of the external power receptacle and pin A/L of the EPC
    . pin C of the external power receptacle and pin A/M of the EPC.
       1 If the feeders are not correct:
  • Repair or replace as necessary.
       2 If the feeders are correct:
Subtask 24-41-00-860-054-A ** ON A/C NOT FOR ALL
C. Do this procedure to make sure that the system operates correctly.
   (1) Energize the aircraft electrical circuits from the external power AMM 24-41-00-861-002.
   (2) De-energize the aircraft electrical circuits from the external power AMM 24-41-00-862-002.
[Rev.8 from Aug 2018] 2026.04.04 04:26:54 UTC
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