Most engineers won't tell you that earthing is very important in the proper operation and long-life of not just the equipment you are connecting to a power source but all other electronic or electrical devices connected to the same power source.
In a data center, the proliferation of servers, desktops, network switches and other electronic devices all hooked to the same power delivering devices such as PoE enabled switches providing power to end devices, it creates a lot of harmonics.
Harmonics can cause dangerous and critical performance situations for many business and consumer users. Bad earthing and bonding will affect UTP and shielded installations.
This tyco paper explains what can be done to correct problems arising from bad earthing and bonding.