French term (edited): champ (de tôle non protége)

champ would more-commonly be written chant, meaning 'edge' in your context.

See: https://www.editions-eyrolles.com/Dico-BTP/definition.html?i...
CHANT OU CHAMP - n.m. :
[Div.] Face étroite d'un élément de section rectangulaire. Chanlatte chevron chanlatte liteau Chanfrein Chanfrein chant 157


The ST warns that the cable's insulation may be damaged if it touches the raw edge of the sheet metal, and this can be avoided by using a couvre-champ/t, which would probably be some kind of grommet.

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Note added at 2 hrs (2023-11-04 16:59:36 GMT)
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In the image posted by asker, we can see a bunch of cables passing through a rectangular hole in a thin sheet metal enclosure. Just below the dark blue cable tie, you can see how the the underside of the cables is resting against the chant, with a risk that the insulation may be damaged if the cable moves for any reason (vibration, etc.) and rubs against the sharp edge of the hole.

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Note added at 1 day 0 min (2023-11-05 14:03:52 GMT)
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@Asker
The dispatch of Kudoz and forum notifications has been utterly unreliable for some time now. See here, for example: https://www.proz.com/forum/prozcom_technical_support/364303-...