Apple Power Macintosh 8100 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
IMPORTANT Some cards may need to be installed by an Apple-authorized
service provider. Check the information that came with the card.
Follow these steps to install a NuBus expansion card or a DAV card.
1 Turn off and unplug the computer.
Make sure the computer is turned off and unplugged.
2 Loosen the four large screws at the corners of the back panel.
Do not remove the screws or the back panel.
113 Installing an Expansion Card