Asking for a friend. If someone is here on non-EU B permit, tied to employer, working full time, can they pick up a part-time job for another employer without having to get another permit (with full-time employer fully agreeing to part-time job).

Thank you!

No

That was the short answer.

The long one is that regardless of permit, this person already has 1 full time job. Working more is considered breach of contract because the person is not well-rested, therefore productivity takes a dive. In a office consequences are only making mistakes in Excel, if the work implies driving or operating machines, this is life-threatening. So, getting the approval from 1st employer will be an interesting situation.

Of course, we all have worked more than 42-43 hours per week for some periods. But, it doesn't work on the long term.

What if the 1st contract is 70% (minimum for applying a working B permit)? Can he accept the part-time job then?

No, because the permit is tied to the employer. And if that's the minimum % required for a permit the other employer would never get a permit for the 30% part which would be the only way to do it.

And this friend has skills that others in Switzerland or EU can’t provide? Really?

I don’t think your friend would like the authorities to ask that question.

Working in Switzerland for non-EU nationals is not a right, it’s a privilege. The rules may be silly, but they still must be followed.

Yes, this person would have specialized skills so the employment all works out and their first 100% employer would agree to the extra job. I just wondered about the work visa. Do all non EU get work visas connected to their employer?

Initially yes.

Also have a look at the thread on the implications of wanting to have 2 jobs on taxes and social security.