# What size ground wire do I need for a 75 kVA transformer?

## What size ground wire do I need for a 75 kVA transformer?

For example, a 75-kVA transformer with a 480-volt primary and 208/120 volt, three-phase, four-wire secondary would have a maximum primary current of 90 amps and a maximum secondary current of 208 amps. The secondary conductors would be required to be 4/0 copper using 75 degrees Celsius insulated (or better) conductors.

## Do transformers need to be grounded?

Transformers themselves are not and do not have to be grounded. Grounding is mostly used for increased safety when it comes to appliances utilizing the mains electricity. You need to be aware though that since by using these transformers you forfit ground protection.

**Do transformers need ground rod?**

Utility companies will also frequently require a driven ground rod or other type of grounding electrode be supplied for the ground-mounted transformer or a wrapped electrical grounding electrode (commonly called a butt-wrapped electrode) on the bottom of a wooden power pole.

### What size breaker feeds a 75 kva transformer?

The rated current of the transformer can be used as the basis for a breaker. The rated current of a 3 phase, 75 kva transformer is 112 Amps, which is 25% of the rated current of a 125 Amp breaker.

### How many amps does a 75 kva transformer use?

75 KVA is equal to 75,000 VA. (K= 1,000) The full value in VA, 75,000 divided by 1.732 = 43,302, which is then divided by the Voltage 208V = 208.2 Amperes. This is a “Three Step Division”, technique: VA / 1.732 / Voltage = Amperage.

**How many grounding does a transformer need?**

In addition to the main solidly grounded system that supplies the facility, two different solidly grounded systems are established at the secondary of each stepdown transformer. A neutral of each transformer is bonded to the transformer enclosure and connected to the grounding electrode of the system.

## How many earthing is required in a transformer?

Only one earthing system need to be installed at distribution transformers.

## Why do we need neutral grounding in transformer?

Neutral transformer grounding serves as a permanent and continuous conductive path to “earth” with sufficient ampacity to carry any fault current, sufficiently low impedance to limit the voltage rise above ground, and facilitates the operation of the protective devices in the circuit.

**How many ground rods does a transformer need?**

two grounding electrodes

Not installing a third grounding electrode. The NEC requires a minimum of two grounding electrodes, unless one electrode has a resistance to earth less than 25 ohms.

### How many amps does a 75 kVA transformer draw?

208.2 Amperes

75 KVA is equal to 75,000 VA. (K= 1,000) The full value in VA, 75,000 divided by 1.732 = 43,302, which is then divided by the Voltage 208V = 208.2 Amperes. This is a “Three Step Division”, technique: VA / 1.732 / Voltage = Amperage.

### Is a main breaker required after a transformer?

A. No. Lighting and appliance branch-circuit panelboards supplied from a transformer, as permitted in 240.21(C), must have overcurrent protection for the panelboard on the secondary side of the transformer.