> For the complete documentation index, see [llms.txt](https://bell-505-guide.gitbook.io/bell-505-maintenance-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bell-505-guide.gitbook.io/bell-505-maintenance-guide/system-descriptions/electrical-systems/electrical-power/external-power.md).

# External Power

The external power provides a connection for an external power source to crank and start the engine and to operate helicopter systems, which prevents the depletion of stored electrical power. The external power consists of the external power receptacle.

## External power receptacle

The external power receptacle is a standard 28 VDC aircraft external power type which permits the use of a standard 28 VDC power source. It is mounted on a dedicated support bracket assembly on the right side of the mid fuselage aft bulkhead, under the Electrical Power System Unit (EPSU). Its access panel is in the right aft fuselage panel.

## Operation

The electrical power from the external power source is applied through the ‘+’ connection of the external power receptacle and the heavy gauge cable to the GROUND POWER connection of the EPSU.

The electrical power from the external power source is also applied through the S connection of the external power receptacle to the GROUND POWER CONTROL connection of the EPSU.

The EPSU then distributes the electrical power to the helicopter systems through the main bus.

The EPSU also applies the electrical power to the starter generator to crank the engine.

The electrical power return is from the helicopter structure through the heavy gauge cable and the ‘-’ connection of the external power receptacle to the external power source.


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