## What is thumb rule in electrical?

Thumb Rules. Cable Capacity. For Cu Wire Current Capacity (Up to 30 Sq.mm) = 6X Size of Wire in Sq.mm. Ex. For 2.5 Sq.mm = 6×2.5 = 15 Amp, For 1 Sq.mm = 6×1 = 6 Amp, For 1.5 Sq.mm = 6×1.5 = 9 Amp.

Table of Contents

**How much current can 2.5 sq mm wire carry?**

For Cable Current Capacity = 4X Size of Cable in Sq.mm, Ex. For 2.5 Sq.mm = 4×2.5 = 9 Amp.

**How much current can 1.5 sq mm wire carry?**

The 1.5 mm wire load capacity is controlled at 2860W. Reasonable and safest.

### How do you calculate square mm of wire?

Calculating the Area of a Cable

- As an example, let’s assume we want to know the area for a copper conductor cable having 41 strands of 0.20mm wire.
- 0.20 × 0.20 = 0.04.
- 41 × 0.0314 = 1.2874.

**How do you calculate cable size from KW?**

To calculate the Cable Sizing one needs to divide the voltage running through the cable by the target current. For instance, If your wire has a voltage current of 150 Volts and your target is 30 then you divide 150/30.

**Which wire is used for AC?**

Air Conditioner Wire Size Chart (1.5-5 Ton Units)

Air Conditioner Tonnage: | Max. Wattage (At 10 EER): | Min. Wire Size: |
---|---|---|

1.5 Ton | 1,800 Watts | 18 AWG Wire |

2 Ton | 2,400 Watts | 18 AWG Wire |

2.5 Ton | 3,000 Watts | 14 AWG Wire |

3 Ton | 3,600 Watts | 12 AWG Wire |

## How do I calculate what size wire I need?

How do I calculate wire size for motors?

- Multiply the resistivity (Ω•m) of the conductor material by the peak motor current (A), the number 1.25, and the total length of the cable (m).
- Divide the result by the voltage drop from the power source to the motor.
- Multiply by 1,000,000 to get the result in mm2.

**How do I calculate cable size needed?**

To calculate the Cable Sizing one needs to divide the voltage running through the cable by the target current. For instance, If your wire has a voltage current of 150 Volts and your target is 30 then you divide 150/30. This gives you your target resistance of 5 which is required.

**How much voltage drop is OK?**

The National Electrical Code says that a voltage drop of 5% at the furthest receptacle in a branch wiring circuit is passable for normal efficiency. For a 120-volt 15 ampere circuit, this means that there should be no greater than a 6 volt drop at the furthest outlet when the circuit is fully loaded.

### Is MCB required for AC?

Buying an MCB After the stabilizer, the next important accessory needed for your AC’s long life is the MCB- Miniature Circuit Breakers or Molded-case Circuit Breaker. The MCB is an automatically operated electrical switch which protects appliances from damage caused by overload or short circuit.

**How many mm is AC wire?**

2.5mm^2 wire is good for 18A inside a wall, so you are limited by the 15A sockets. A 220V 15A socket can deliver 3.3kW, and even if the voltage drops to 180V it can still do 2.7kW. Your aircon requires 1.55kW so there is enough power available.

**What is 10mm cable used for?**

10mm earth cable is suitable for fixed wiring of electrical equipment, lighting and household appliances Usually used for grounding wires.