Charging a Macbook Pro
When at home and sat at my desk, if my MacBook pro is permanently plugged in, is a 20W standard Apple plug power supply OK.
When I take the MacBook out, I can then use it with its 96Watt supply adaptor
Question marked as
I strongly advise against doing that.
The MBPro and its charger are designed to work together at higher power levels. The little 20w iPhone charger is not designed to work with devices that require higher power. Even if you try it and it works, it is likely to get very hot, ultimately burning out or worse. And you don't even want to imagine the worse.
MBPros come with a 70w, 96w or 140w charger for a reason. Get a second charger that is appropriate for your MBP.