On tue dec 2 2014 at 7 52 pm electrical notes articles wrote.
Cable tray sizes calculation.
Cable raceway tray support calculations.
Lbs ft inside tray depth.
Not required outside diameter cable qty cable size weight lbs ft total cable weight.
A 50 fill ratio should equal the maximum number of cables pulled in a given cross section.
This is typically in a raceway cable tray or conduit in a cable burried in the earth or in open air.
Minimum allowable tray.
Cable id cable o d.
It is based on cable type insulation type and the cable installation method.
Here voltage drop for 70 sq mm cable 5 8 is higher than define voltage drop 5 so either select higher size of cable or increase no of cable runs.
Distance enter the one way length of the wires in the circuit in feet.
If we select 2 runs than voltage drop is 2 8 which is within limit 5 but to use 2 runs of cable of 70 sq mm cable is not economical so it s necessary to use next higher size of cable.
Voltage drop choose the maximum percentage of the source voltage drop.
Cable tray is sized based on the number and type of cables required for the current and future need.
9 to begin a new calculation return to the input screen and select the clear button.
The current ratings are selected from tables 4 to 21 in as nzs 3008.
The sum of the cross sectional areas of all cables cannot exceed 50 of the trays fill area.
Cable trays may be filled 50 when using control or signal wiring.
Tables 4 to 21 are based on an ambient temperature of 40 c and a ground temperature of 25 c.
Cable tray should be perforated and 20 spare capacity.
Per the national electrical code article nema 392 9 b cable tray fill calculations and cable tray sizing calculations will be computed as follows.
Iii no of single conductor cables 2000 volts in the cable tray nec 392 12.
It is recommended not to exceed a voltage drop of 5.
Calculate cable tray width calculate cable tray area calculate cable tray length calculate cable tray weight calculate remaining width of cable tray calculate remaining area of cable tray free download.
Provides quick and easy results for the conduit fill percent per nec guidelines.
Calculate size of cable tray for following cable schedule.
The sum of the diameters of all cables rated 2001 volts or over is not to exceed the cable tray width.
Solid bottom cable tray when using solid bottom cable tray the allowable cable area is reduced from 50 to 40.
Cable are laying in single layer in cable tray.
1 2 no s of 3 5cx300 sq mm xlpe cable having 59 7mm outer diameter and 5 9 kg meter weight 2 2 no s of 3 5cx400 sq mm.
Conduit fill calculator conduit fill is the percent of area inside the conduit taken up by the cable s.
Ii no of cables more than 2100 v in the cable tray.
The cable sizing calculator considers solid or stranded copper conductors only.
