Siemens SIMATIC S7-300 - Manual (Page 20)

3 Installing and
wiring the hardware
16
SIMATIC S7-300 Getting Started for First Time Users
Getting Started, 04/2007, 6ZB5310-0NC02-0BA0
3.2 Installing the components
In this section, we show you how to:
• Install and ground the mounting rail
• Install the modules on the mounting rail
• Insert the front panel connector
Installing and grounding the mounting rail
1. Screw the mounting rail to the
subsurface. Use two M6 screws
for this.
2. Connect the mounting rail to the
ground wire.
The prescribed minimum cross-section for the cable to the protective conductor
is 10 mm
2 .
Note the following information when installing the mounting rail:
• Make sure to maintain a clearance of at least 40 mm above and below the
mounting rail. This is needed to satisfy the requirements for thermal conditions
(heat dissipation and ventilation of the module) and to facilitate the installation
(mounting and removing, wiring).
• If the subsurface is a grounded metal plate or a grounded device panel, make
sure you have a low resistance connection between the mounting rail and the
subsurface. This produces a uniform reference potential.