French term (edited): départs UPS RESEAUX 1 & 2

You will find 'départs' already in the archive, with a choice of terms; 'outgoing feed' works in many cases; sometimes, when it is clear fom the context just what is being 'fed', you can simply use 'feed', sometimes 'feed to'... and even 'output (to)'
The only thing that's important is to make sure that it is clear about the 'from' and 'to' aspect, which is normally clear in FR but can be ambiguous in EN.
Note that we don't know for sure if this is feeding one or two UPS that power circtuits 1 & 2, or whether in fact it is 2 circuits feeding 2 separate UPS — this may be clear from the diagrams you have?
I am interpeting this as bieng the (mains) power outgoing feeds TO supply the UPS; it could also mean the outgoing feeds FROM the UPS, but from the context given, that seems a lot less likely to me.

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Note added at 2 hrs (2023-02-14 11:47:12 GMT)
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By the way, I'd also think twice about your 'copper connections'
'liaison' in FR has much more of the notion of 'a conductor running between' than it would necessarily have in EN, where the emphasis is often on the notion of the 'physical connection between A and B'
Dpending on what your context is really referring to (or saying about it), you might do better with a word like 'link' etc.