Create a 3-Phase Board

We will now create a 3-phase and neutral distribution board for the workshop which is fed from distribution board 1, fuseways 2L1, 2L2 & 2L3.

  1. In the left tree right-click circuit 2L1 then select “New” -> “Board”.
  • Alternatively, select circuit 2L1 then on the “Specification” tab under “Topology” select “Sub-Main”.
  1. In “Type” select “Distribution Board”.
  1. Continue filling out the board details, then click OK.
  1. Enter the supply cable details.
  • Once entered, it is easier to enter the supply cable details on the supply phases without the distribution board being “open”, therefore at this stage do not press on the “+” button. If you do, you can always shrink it again by pressing on the “-” button.


Sometimes it can be confusing with regard to the supply fuse, the supply cables and the downstream boards. If you are unsure then sketch it out on a notepad, drawing the supply fuse, supply cable etc. Name the distribution board and fill out the “Fuseway” number; as this is a 3-phase board, count the number of 3-phaseway groups. In this example, we have chosen 6 x 3-phaseway groups (18 x single phase ways).
  1. Now enter the protective device details under the “Protective Device” tab and the results under the “Results” tab.
  2. Now that all the details have been entered for fuseway 2L1, with fuse way 2L1 highlighted, “Copy” either here or from the tool bar.
  1. Highlight the second supply phaseway (2L2) and paste then repeat for 2L3.
  • If you wish to copy and the paste to multiple phaseways at the same time, copy 2L1, then holding down the keyboard “control” key, highlight fuseways 2L2 and 2L3. Once both are highlighted, release the keyboard “control” key, go to “Paste” on the toolbar and enter. That’s all three supply phases done.
  1. Although we have copied 2L1 to the two other phaseway supplies (2L2 & 2L3), we need to confirm the two other supply phases to this distribution board so that the software recognizes that this is a phase-group. On the “Specification” tab under “Board Fed From” click the “Select” button.
  • A screen will open showing the available circuits on the supplying board (Distribution Board 1). In the bottom pane circuit 2L1 is automatically added.
  1. In the middle pane, hold down the Control key and click circuits 2L2 and 2L3 to select them, then click “Add”.

    The circuits are aded to the bottom pane.

  2. Click OK.

    The board “Specification” tab should now look like below, showing all 3 phaseway supplies.

  1. On the “Specification” tab, fill in the “Location” and “Make” fields, then select the “Results” tab.

    Note that the external earth loop has not been automatically filled in at this point because the bonding has not been verified.

  1. Select the “Bonding” tab then enter the details.
  • As the circuit supplying this distribution board has had its details entered, all these details including the test results will be automatically filled in except the external earth loop on the board “Results” tab.
  • If the “Bonding” = “No” the earth loop result from the supply end of the circuit test data will update the “External Earth Loop” field automatically.
  • If the “Bonding” = “Yes”, therefore not connected to the upstream earth, obviously the external earth loop reading would not be the same as the supply circuit earth loop reading and would need a new test result entered. (See a board that is outside of the equipotential zone that has had its earthing arrangement changed to a TT earthing system - this is dealt with later).
  • If “No” is chosen, the end of the supply circuit earth loop reading entered earlier is automatically entered into the “External Earth Loop Reading”. You have to enter both “Prospective Short Circuit……” fields with their respective readings.

Record 3-phase Circuits

Our first fuseway supplies a 3-phase direct-on-line compressor wired in 4.00 mm single insulated cables encased in 50.00 mm x 50.00 mm trunking. The current carrying capacity of the cable is rated at 28 amps and has a protective device rated at 40 amps for start up load. The compressor has a rated running current of 22 amps and has an overload device set at 23 amps.

  1. Highlight the first fuseway of the 3-phase group, go to “Topology” in the right hand screen and choose “Radial”.


14. Next go to the “Phaseway Group” and in this case, we will choose a 3-phase 400v without a neutral.


Now we need to select the other fuseways for the two remaining phases.

  1. In the top pane of the “Select Phaseway” window, highlight the two other phase ways.
As phase way 1L1 has already been allocated, it is not in the pane to be chosen.
  1. Click “OK”.
  1. Verify that the correct “Other fuseways” are entered, enter the “Description” field and click “New” to choose the cable.
  1. We have chosen a single insulated 6491x cable, with a CSA of 4.00 mm. We now need to choose an installation method, therefore click on “Installation Method”.
  • As the circuit is wired in trunking, therefore reference method B has been ticked. As you can see, the cable is rated at 28 amps.
  1. Now we need to choose the “Earth Cable”, the earth format is “Steel Trunking” having a size of 50 mm x 50 mm.

The software will calculate the actual CSA of the steel (greyed out).

  1. Fill out the protective device details. As this compressor has an overload device to protect the motor, tick the “Overload Device Present” box and enter the overload setting.
  1. Enter the test results for this circuit.

    Although the protective device details are entered for the first phaseway, the details are not showing on the fuse “chain”. This is because the details for the other 2 x phaseways have not yet been entered.

  1. In the left tree, right-click circuit 1L1 then select “Copy Circuit”.
  1. Highlight the other 2 x fuseways, click on “Paste” on the toolbar, or right click your mouse and copy and paste individually.
  • Now the other fuseways have their data automatically pasted in, the protective device and overload details now show. When a compliance check is carried out after all data has been entered, the circuit will pass for overload due to the setting of the overload device.
  • Note the Zs reading (0.50) is higher than the “Allowable Zs” and Zs*DF Local and is the highest reading in the “Chain”. When the compliance check is carried out, an automatic observation will be offered.


While we are on the subject of the “Over Load Device Present”, say you had an inductive load which therefore, could cause an overload on a single phase circuit. The circuit has a protective device in excess of the current carrying capacity of the cable. There are no spurs or branches taken from the circuit and the circuit has a fused spur unit with a 13 amp 1362 fuse (less than the current carrying capacity of the cable) adjacent to the load. You can enter the fuse size (13 amps) in the fused spur unit as the “Over Load Device Present”, therefore, enabling the circuit to “Pass” for overload protection.

➲ Next: Add Split Circuits.