61 00... Notes on electrical properties of carbon body

NOTE: The body of BMW i vehicles consists of several carbon body components linked together by means of adhesive.
(carbon: carbon fibre reinforced plastic)

IMPORTANT: Carbon body components are electroconductive.
Nonetheless, the electrical conductivity of carbon is lower than the one of steel or aluminium.
Therefore, the carbon body cannot be used as the ground of the vehicle electrical system.
The adhesive partially prevents the electrical current flow between the carbon body components.

IMPORTANT: In the case of a short circuit between vehicle electrical system and carbon body, the current may be below the triggering threshold of electrical fuses.
If the electrical fuse was not triggered in such case of a short circuit, the carbon body components may be damaged due to high heat load.

To prevent damages on the carbon body, it is crucial to adhere to the following notes:

Carbon body may not be used as ground.
Measurements may only be carried out to ground/ground support point, not to the carbon body.
Ensure a correct ground contact according to the wiring diagram is set before carrying out checks relating to electrical components.

In case of damages of electrical components, proceed as follows:

Disconnect high-voltage system from power.
Disconnect battery ground cable.
Repair damaged electrical components.
Check carbon body for eventually visible surface damage caused by heat load in the area of damage of electrical components.
Contact Technical Support in cases of doubt.