Hi everyone, What are the general steps and precautions to be taken for connecting Ring main unit to a distribution systems?

The most important step is to ensure that everyone is qualified to work at these voltage levels, especially if there is any energized equipment nearby.

Competent engineering staff that have already done this before should be on site.

The manufacturer's instruction and installation manuals must be read and followed.

Make sure that there is a safety lockout system in place, that everyone understands how it works, and that it must be followed, no exceptions.

Alan

Before closing the ring make sure that Phase sequence is OK. Also check if the mechanical interlocks work on both ways.

Obviously ensure that is it tested and commissioned properly. The biggest trap with RMUs is that the normally have line-side earth switches, so make sure you have correct interlocking to prevent closing an earth onto a live bus (or switching instructions at least)

In RMUs normally supply comes from two directions hence it essential to know how the system is connected.

Thank you everyone.Could you please explain what are the commissioning test that we have to conduct on the rmu?

first you have to disconnect the supply after confirmation power off you have to reach that point where you want to install RMU .at this point you have to cut wire and get selection input and output terminals
ranjan is right rmu has bi directional power supply so, incoming power you have to choose this line as input and after that you can connect two output terminals through rmu as you consider remaining cut wire another also output one and second output as you like