DC ESSENTIAL DISTRIBUTION - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. General

DC Essential Distribution - General ** ON A/C NOT FOR ALL

The essential 28 VDC distribution network corresponds to busbars 4PP, 8PP and associated sub-busbars.

** ON A/C NOT FOR ALL

2. Component Location

DC Essential Distribution - Component Location

FIN	FUNCTIONAL DESIGNATION	PANEL	ZONE	ATA REF
** ON A/C ALL
8PH	CNTOR-DC SHED ESS BUS	106VU	125	24-62-55
6PH	HOLDER-FUSE	105VU	126	24-62-00

** ON A/C NOT FOR ALL

3. Operation
The essential 28 VDC distribution network can be supplied:

either by busbar 3PP (in fact by TR1) in normal configuration,
by Essential TR in case of loss of one main TR, loss of both main TRs or in emergency configuration.

Part of this network (busbar 8PP) can be shed in emergency configuration during RAT extension and as soon as the landing gear is extended (case of battery supply).
In case of loss of supply, a warning is triggered on the ECAM system,

DC Essential Distribution - ECAM Warnings ** ON A/C NOT FOR ALL

In case of loss of busbars 4PP or 8PP, the ELEC page is automatically displayed on the ECAM lower display unit:

DC ESS BUS FAULT - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

DC ESS BUS SHED - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

The essential 28VDC distribution network can be supplied :

either by busbar 3PP (in fact by TR1) in normal configuration
by Essential TR in case of loss of one main TR, loss of both main TRs or emergency configuration.

Part of this network (busbar 8PP) can be shed in emergency configuration for low aircraft speed.
In case of supply loss, a warning is triggered on the ECAM system

DC Essential Distribution - ECAM Warnings ** ON A/C NOT FOR ALL

In case of loss of busbars 4PP or 8PP, ELEC page is automatically displayed on ECAM lower display unit.

DC ESS BUS FAULT - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

DC ESS BUS SHED - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

The essential 28VDC distribution network can be supplied:

either by busbar 3PP (in fact by TR1) in normal configuration
by Essential TR in case of loss of one main TR, loss of both main TRs or in emergency configuration.

Part of this network (busbar 8PP) can be shed in emergency configuration for low aircraft speed.

NOTE: The sub-busbar 802PP of the busbar 8PP is shed if the Constant Speed Motor/Generator (CSM/G) is on line and if the forward landing gear is not locked up.

In case of loss of supply, a warning is triggered on the ECAM system

DC Essential Distribution - ECAM Warnings ** ON A/C NOT FOR ALL

In case of loss of busbars 4PP or 8PP, the ELEC page is automatically displayed on the ECAM lower display unit.

DC ESS BUS FAULT - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

DC ESS BUS SHED - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

The essential 28 VDC distribution network can be supplied:

either by busbar 3PP (in fact by TR1) in normal configuration,
by Essential TR in case of loss of one main TR, loss of both main TRs or in emergency configuration.

Part of this network (busbar 8PP) can be shed in emergency configuration during RAT extension and as soon as the landing gear is extended (case of battery supply).

NOTE: The sub-busbar 802PP of the busbar 8PP is shed if the Constant Speed Motor/Generator (CSM/G) is on line and if the forward landing gear is not locked up.

In case of loss of supply, a warning is triggered on the ECAM system

DC Essential Distribution - ECAM Warnings ** ON A/C NOT FOR ALL

In case of loss of busbars 4PP or 8PP, the ELEC page is automatically displayed on the ECAM lower display unit.

DC ESS BUS FAULT - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

DC ESS BUS SHED - Upper and Lower ECAM Display Unit ** ON A/C NOT FOR ALL

It must be noted that due to segregation rules between DC channels, the TR2 cannot supply the DC ESS busbar.

[Rev.10 from 2021] 2026.03.31 23:25:27 UTC