Rockwell Automation Allen-Bradley ControlNet 1734-ACNR User Manual page 178

C-16 Determine Your ControlNet Media Requirements
Publication CNET-UM001C-EN-P - November 2005
Do not let any metallic surfaces on the BNC connectors,
ATTENTION
plugs, or optional accessories touch grounded metallic
surfaces. This contact could cause noise on the network.
All exposed metal must be covered with either intrinsically
safe blue sheaths or another form of sufficient insulation.
If you are installing a bullet connector for future tap
IMPORTANT
installations, count the bullet as one of the tap allotments
on your segment (and decrease the maximum allowable
cable length by 16.3 m [53.5 ft]).
This helps you avoid reconfiguring your network when you
install the tap.