Apple Power Macintosh (7100 Series) - Manual (Page 123)

NuBus power requirements
The combined power consumption of NuBus cards must not exceed the limits
specified for your Macintosh model. If you have more than one NuBus card
installed, check the information that came with your cards to make sure that
their power consumption is within the limits specified in the Technical
Information booklet.
Installing a NuBus card
Before you begin, have a regular flathead screwdriver at hand.
1 Turn off and unplug the computer.
Make sure your computer is turned off and unplugged.
2 If the monitor is on top of the computer, disconnect the monitor and set it to one side.
3 Using a flathead screwdriver, loosen the large safety screw at the back of the computer.
Do not remove the screw or the back panel.
Loosen the screw.
113 Installing an Expansion Card