Is installing a 48 port blade in Brocade DCX8510 non-dirusptive? What precautions should be taken?
yes it is non-disruptive.
just read the procedure available in the switch hardware guide.
The 8510 Hardware Reference Manual referenced above can be found here:
(Replacing a Blade)
I' m not sure what your 8510 configuration is, but you should also take a look at the release notes for the firmware you are runniing.
Specifically the sections below:
"Typical Power Supply Requirements Guidelines for Blades in DCX 8510"
"DCX 8510-8/DCX 8510-4 Blade Support Matrix"