Preparing to install sub-mains for a new electrical switchboard

This guidance for electricians asks questions and uses examples to help remove or reduce the risks to health and safety when installing 150mm² single double insulated (SDI) sub-mains for a new electrical switchboard.



You can adapt this example to your own job and help create a safer work environment.

One in three injuries on construction sites involve everyday tools and equipment. So make sure you don’t take shortcuts with your gear and use the right tools for the job.

Take time to prepare your site. Stop, Step back, and Think.

1. Stop

What job needs to be done? Do I have the right tools?

What's the job?

Installing sub-mains for a new sub-board along existing cable tray. The cable tray is 6m above ground. It has 2 left and right hand bends and is 75m long.

List the tools you need

  • forklift (to unload and move cable drums and bulk equipment)
  • cable drum stand
  • tag rope
  • cable winch
  • cable sock
  • assorted cable rollers
  • hydraulic cable cutters
  • assorted hand tools
  • extension ladder
  • electrical test equipment
  • power drill
  • portable two-way radios

2. Step back

Take a moment to ask:

Where is the job located?

In an old factory.

How long will the job take?

2 days.

How many tradies do I need?

  • 1 electrician for preliminary work
  • 4 electricians for installation work
  • 1 forklift driver.

What do I have to do?

Pull in the cables and secure them to the tray from the main switchboard room to the new sub-board.

What's been quoted as part of the job?

  • Materials: electrical cables and fixings
  • Labour
  • Hire of equipment.

Will the work impact on others?

No. The work is happening on the weekend, when the factory is shut down.

What hazards need to be fixed before I start?

  • Isolate all cables on cable tray.
  • Check and control the risk of contact with live parts in the switchboard room.

3. Think

Make sure your equipment is in safe working order. Know what to do when arriving on site.

Are the tools in good condition and appropriate to the task?

No. The drill needs to be tested and tagged. The batteries in the two-way radios need to be recharged.

Do I have all the right tools and equipment for the job?


What do I need to do before I'm on site?

  • Organise the site to store cables and equipment.
  • Order cables for early delivery.
  • Order 2 scissor lifts for delivery early Saturday morning.
  • Order a cable winch, rollers and cable stands.
  • Ensure that the factory supervisor has a valid forklift licence.

What do I need to do when I arrive on site?

  1. Report to the factory supervisor and get inducted onto the site.
  2. Review and revise Safe Work Method Statements (SWMS) for high risk work.
  3. Induct employees into the SWMS.
  4. Instruct operators on safe operation of scissor lift.
  5. Carry out the daily checks on the scissor lift and fork lift.

Check Personal Protective Equipment (PPE)

  • eye protection
  • long sleeve shirts
  • safety boots
  • protective gloves

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