Answer / abduljameel

Selection of cable size based on the following:
1.Load current
2.Length of the load from the source.
3.Cable laying area(underground,cable tray,area)
4.Permissible voltage drop.

Kindly refer cable manufacturer catalgue for selection

Answer / nitiyanandam

FOLLOWING EACTORS R CONSIDER TO SELLECTION OF CABLE

1.sellection of condutor ALU or CU
2.cable insulation PVC or XLPE
3.load current.
4.lenth of conductor.
5.voltage drop.
6.temperature.
7.apply voltage.

Answer / madhav

While other answers are general procedures for selection of
cable, underground cable laying is different, AFTER having
taken the above factors into consideration.

The laying of underground cable should also consider the
permissible conductor temperatures, ambient temperature,
number of cores and mode of laying (single cores or
multicores), etc. The maximum current carrying capacity
also varies with the type of cables and its insulation
properties.

Cable laying is also of several types. In case of single
core cables, they could either be close together or
seperated by one diameter of the cable. That could also
cause differences in current carrying capacities.

In general, for a loaded 5 core cable when laid in ground,
the derating factor could be 0.7 times the rated current
carrying capacity of the cable.

Answer / william lobo.

In case of laying of single core cables then trefoil
formation should be adopted. i.e. R Y and B phases should
be clamped with alluminium clamp only or Stainless steel
clamp to avoid induction.

Derating factors are also to be considered which depends on
the distance of cable laid from each other. If cables are
touching one another incase of multicore cables then
derating factor will be about 0.5 to 0.6 or so.

why we use isolation transformer?

2 Answers   Godrej,

---

while doing high voltage test on 11kv/433 distribution transformer why we only give 28 kv on hv side and 3kv on lv side for power transformers what is the value what factors it depends

0 Answers   Enercon,

---

What is difference between PVC cable & XLPE cable?

14 Answers   Intertek,

---

how to calculate the powerfactor in induction motor having name plate details? for example 1 h.p motor 1.86 A 415 V

6 Answers  

---

what is the difference between equipment earth and system earth.

1 Answers   Hofincons,

---

We have drive feeding an output contactor for a 5000 hp motor @ 5kV application. The motor FLA is 629amps x 1.25% service factor = 786.25 amps The cable that we current have in place between the drive and the output contactor is 350kcmil- MV-105 (parallel cables). Per the NEC table 310.60 (C) (69). This show the cable ampacity is at 615 amps per cable for a rating of 1230 amps. We have derated the cable for the cable tray and the multiple cables application and our calculations show that after the correction factor factor we are at 922amps. 1230 amps x .75% correction factor factor = 922.5 amps. The customer is driving us to then use another safety factor of .25% off of the already derated cable. Can you please provide a longhand calculation for your solution on this application?

0 Answers   Siemens,

---

What is maximum demand?How can we caluclate it?

3 Answers   TATA,

---

wich type of cable is selected for wiring of 20hp motor?

5 Answers   Alchemist,

---

What is the significance of %Z in case of transformer?

1 Answers  

---

when we have to purchase the transformer by own i.e how much load will preferred HT connection?

0 Answers   Power Square,

---

Why inverter rating in KVA?

3 Answers  

---

condider as 100 w lamps glowing . for completing a one unit how much time it should glow

3 Answers   Avalon,

---