Electrical Design Software | Elecdes Design Suite by Scada Systems Ltd

Power Numbers for Raceway, Cables and Wires

Power number description

The power number represents the power compatibility of a cable or wire when compared to other cables or wires. Sensitivity to electromagnetic interference is the usual use for the power number.

As a simple example, an instrument cable should have a different number from the power cable for a motor.

The power number informs the automatic routing functions of Paneldes which cables to keep separated from each other. Paneldes will only route conductors through raceway with the appropriate power number.

  • Each cable or wire has a single power number.

  • Each raceway segment can have one or more power numbers.

  • You can define the compatibility for each number 0...32768.

Power number "0"

The power number zero, "0", is a special number that disables the power separation feature of the automatic routing functions.

  • A cable or wire with power number "0" can be placed in ANY raceway segment.

  • A raceway segment with power number "0" can carry ANY cable or wire.

Incompatible power numbers

Although connected raceway segments may have different power numbers, if there is not at least one common power number between two raceway segments, then they cannot be connected together.

For example: a segment with power numbers "1-4, 9" can be connected to a segment with power numbers "3, 12" but not to a segment with power numbers "5-7,11".

Thus if two segments appear to be joined correctly in the model yet no route can be found through that junction, the segments may not have any common power numbers.

Point separated power numbers

Power numbers with different "point" values can be used on raceway segments in close proximity to prevent them from being connected together. A point value is added to a power number by adding a decimal point then fractional digits.

For example: "3.1" is power number "3" with point value "1".

The power number is the number before the dot. This is the number used when Paneldes checks if a cable can be carried by the raceway segment. However, when Paneldes is connecting segments, it will not connect two segments together if they have different point separated power numbers. A raceway segment with the same power number but no point separation can be connected.

For example: a segment with power number "3.1" can be connected to a segment with power number "3.1" or "3", but not to a segment with power number "3.2".

All of the segments in this example can carry a cable with power number "3".

This method can be used to prevent cross-connection between parallel runs of tray that have the same power number. If each run of tray has a different point separated power number, they can all carry the same cables, but they will not be cross connected between runs.

NEC signals power numbers

If you are using the NEC code to calculate raceway fill, you can set the power numbers that identify control or instrumentation (signals) cables and trays.

See How to Configure NEC Filling.

Power ranges for raceway

The power number for raceway segments can now contain one or more "ranges". This allows you to specify a range of power numbers that the tray can carry.

E.g. If you want a tray to carry all cables from 110 to 480, then enter the text "110-480" into the POWER number attribute of the tray segment.

NB: "1-5" is the same as "1,2,3,4,5"

A raceway segment can have several ranges separated by commas e.g. "110-480, 900-999, 5000-6000"

The power ranges for raceway segments can be set at insert time or with the Global Editor.

Split power numbers for tray / Tray dividers

A raceway segment can, when necessary, be treated as two or more separated sides by "tray splitting" across the tray width. In some designs this would represent a physical divider placed down the length of a tray and in others clamping or tying down cables to keep them separated into groups.

Splitting only works on straight segments of tray.

To split a tray you must enter a complex POWER number setting when inserting or Global Editing the tray. This setting describes the POWER ranges and numbers on each side of the tray and either the percentage of the tray filling capacity (CABLEFACTOR and WEIGHTFCTR), or the physical distance by which it is split.


The text for a split tray is formatted as follows:

  • <power for side A> , <split data A> , <power for side B> , <split data B> , <power for side C> , <split data C> , ...

    e.g. 100-400, N0.6, 500-1000

  • <power for side>

    These parts describe the power ranges for each side just as a normal POWER setting does.

    In the example, side A can carry cables with power numbers in the range 100 to 400, side B can carry cables with power numbers in the range 500 to 1000.

  • <split data>

    Describes the split orientation and either the split width or the proportion of the cable fill capacity that is assigned to the previous power value.

    In the example, N0.6 specifies that side A is the NORTH SIDE (N/S/E/W can be used) and that side A comprises 60% (0.6) of the tray capacity. NB: NORTH is +Y (WCS).

    When there is more than one split, the orientation letter is required on only the first split. All other splits are in order across the tray width.

  • The split is interpreted as a real world dimension if measurement units follow the value, as in the example below.

    "1,4,8", N200mm, 8-12, 150mm, 500-1000

    "1,4,8" is the power range on side A, comprising 200mm of the north side of the tray. Next split is 150mm carrying cables with power numbers in the range 8-12 and the last tray split can carry cables with power numbers in the range of 500-100 in the remaining tray width and is the south side.

    You can use metric or imperial dimensions i.e. mm, cm, m, km, in, ft, yd, '(feet) , "(inches) for slitting the trays.

  • The split is interpreted as a percentage of raceway fill capacity if there are no units following the number, as in the example below.

    "1,4,8", E0.3, 8-12, 0.2, 500-1000

    "1,4,8" is the power range on side A, comprising 30% (0.3) of the tray fill capacity on the east side of the tray. Next split is 20% (0.2) carrying cables with power numbers in the range 8-12 and the last tray split can carry cables with power numbers in the range of 500-100 range in the remaining tray capacity, which will be 50%, and is the west side.

  • To create air gaps between cables in a raceway segment, create splits with an unused power number as shown in the text format below.

    1,N0.3, 99,0.05, 2,0.3, 99,0.05, 3

    The above text will create three cable groups (power values 1, 2 and 3) each with 30% of the tray capacity along with 2 'gaps' using power value 99 each comprising 5% of the tray capacity. This example assumes that power 99 is not used by any cable in the project.

NOTE:

This feature should be used sparingly. Junction segments and corners can not be split and hence long routes with splits may become un-split or cause cables to cross over.

See also

Keeping power separated raceway on different layers

Panel ducting

Raceway

How to tune your model for wire and cable routing

Routing functions description

Route optimisation errors and warnings

Cable filling factor for raceway