Cable Calculations

Question 1

What is the power triangle?

Answer 1

PIV, P = V x I

Question 2

What is the following calculation - “Power = Current x Voltage”?

Answer 2

The power calculation or power triangle.

Question 3

What does Lb stand for?

Answer 3

Design current.

Question 4

What does Ln stand for?

Answer 4

The overcurrent device rating.

Question 5

What does Lt stand for?

Answer 5

The tabulated current carrying capacity of the cable.

Question 6

What does Ca stand for?

Answer 6

Ambient temperature.

Question 7

What does Cg stand for?

Answer 7

Grouped cables.

Question 8

What does Ci stand for?

Answer 8

Thermal insulation.

Question 9

What does Ct stand for?

Answer 9

The type of protective device.

Question 10

What is the abbreviation for “design current”?

Answer 10

Lb.

Question 11

What is the abbreviation for “the overcurrent drive rating”?

Answer 11

Ln.

Question 12

What is the abbreviation for “the tabulated current-carrying capacity of the selected cable”?

Answer 12

Lt.

Question 13

What is the abbreviation for “ambient temperature”?

Answer 13

Ca.

Question 14

What is the abbreviation for “grouped cables”?

Answer 14

Cg.

Question 15

What is the abbreviation for “thermal insulation”?

Answer 15

Ci.

Question 16

What is the abbreviation for “the type of protective device”?

Answer 16

Ct.

Question 17

What is the carrying capacity calculation?

Answer 17

Lt = Ln / CaCgCi*Cf

Question 18

How do you calculate voltage drop?

Answer 18

Voltage drop = (mV/A/m)LbL / 1000

Question 19

What is the maximum voltage drop for lighting circuits?

Answer 19

It cannot exceed 3% of the nominal voltage.

Question 20

What is the maximum voltage drop for every except lighting?

Answer 20

It cannot exceed 5% of the nominal voltage.

Question 21

What is the nominal voltage for lighting circuits?

Answer 21

6.9V.

Question 22

What is the nominal voltage for everything other than lighting circuits?

Answer 22

11.5V.