# How do you size a power cable?

## How do you size a power cable?

Divide the voltage running through the cable by your target current. If, for instance, 120 volts will act on the cable, and you want 30 amps to run through it: 120 / 30 = 4. This is your target resistance, measured in ohms. 30,000 x 1.724 x 10^-8 = 0.0005172 ohm sq.

### What size is standard power cable?

The common sizes of cable are 1, 1.5, 2.5, 4, 6 and 10mm2 – the measurement represents the cross-sectional area of the individual cores. The current-carrying capacity of cable varies according to a number of installation design factors.

#### What size electrical wire do I need?

The rule of thumb that techs will usually go by is that for a 30 amp circuit breaker, 10-gauge wire is the right one to go with. For a 40 amp you need a 8-gauge wire. For a 20 amp, you will need a 12-gauge wire.

Can 1.5 mm cable be used for power?

Depending on the installation method used, the 1.5mm cable has a maximum rated capacity of between 14 and 20 amps, so its right on the limit. The only solutions are to upgrade the cable to 2.5mm or downgrade the MCB to 10amps.

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.

## What cable is used for mains power?

Twin and Earth cables All of your general internal power cables within your home will probably use twin core and earth cabling. As the name suggests, this type of cabling is formed from two cores, insulated with PVC outer sleeve, and an earth core between the two.

### How much load can a 2.5 mm cable take?

Choosing the correct size cable

Conductor Size Current Maximum power (Watts)
1.25 mm2 13 amps Up to 3120 Watts
1.5 mm2 15 amps Up to 3600 Watts
2.5 mm2 20 amps Up to 4800 Watts
4.0 mm2 25 amps Up to 6000 Watts

#### How many amps can 10mm cable take?

A 10mm cable can carry between 40 and 70 amps of current.