Cable Tray Sizing Formula

Number of cable per trench is 1 number of run of cable is 1 run.

Cable tray sizing formula.

3 use the pull down menu to choose the type of cables being used and answer any of the pop up questions. Cable raceway tray support calculations. Diameter of 25sq mm cable 3x28 84 mm. An example how to calculate voltage drop and size of electrical cable photo credit.

Derating factors will be available in cable catalog. An 8awg thhn wire has a cross section of 23 61 square mm 0 03659 square in a 4 awg thw has a cross section of 62 77 square mm 0 09729 square in therefore the wires total cross sectional area is. Get the cable size corresponding to this derated current from the catalog. The sum of the cross sectional areas of all cables cannot exceed 50 of the trays fill area.

Total diameter of all cables laying in tray 119 4 137 2 54 mm. 4 choose the inside tray depth being specified. Generally cable tray sizing is correct when it appears 50 full of cable or wire or when it contains a 50 fill of cables or wire. Cable is directed buried in ground in trench at the depth of 1 meter ground temperature is approximate 35 deg.

Total sum of the diameters. 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. The installation will use cat cable at 19 in diameter 20 lb. Per nec tray sizing instructions 1 insure that macros have been enabled.

Straight section supports installed at 5 foot 1 5m centers are typical. Diameter of 400sq mm cable 2x68 6 137 2 mm. On tue dec 2 2014 at 7 52 pm electrical notes articles wrote. Tray design depth sum of od in total cross sectional areas of all cables.

I load in kw sqrt 3 v in kv p f a the current obtained has to derated since the cable is designed to operate at a defined temperature. Diameter of 25sq mm cable no of cable x outer diameter of each cable. Chart is based on 50 fill of 4 utp category 6 cable o d 21 033lbs ft not maximum loading weight for the tray. Cable tray is sized based on the number and type of cables required for the current and future need.

Practical guide on the amount of cable weight that can be installed tested in accordance with nema ve 1 csa e222 2 126 1. A inside tray area in in 2 d cable diameter in inches f fill ratio in n number of cables the formula is n f a 100 d 2 2 π example. Mm x 4 62 77 sq. Quick tray wire mesh cable tray fill table at 50 fill use the following formula to calculate the number of cables that will result in a particular fill ratio where.

A 50 fill ratio should equal the maximum number of cables pulled in a given cross section. Cable trays may be filled 50 when using control or signal wiring.