Distribution transformer

A distribution transformer is the type of transformer that performs the last voltage transformation in a distribution grid. It converts the voltage used in the transmission lines to one suitable for household and commercial use, typically down to 240 volts. These transformers are pole-mounted if the transmission lines run above ground (see figure 1), and they are pad-mounted (see figure 2) if the transmission lines lie underground, as is the case in many suburban areas. The pad-mounted transformer is usually green and visible on the front lawns of many homes.

• Two types of Transformers
• 

  Figure 1. A single-phase pole-mounted distribution transformer

• 

  Figure 2. A pad mounted transformer box

Connections

Every utility pole has a grounding wire. There is also a grounding wire that accompanies the two 120 volt hot wires that come from the transformer. These two 120 volt wires are 180° out of phase so that if both electric currents are used, there is a combined voltage of 240 volts. This allows for both 120-volt and 240-volt devices to be powered by the same distribution grid.

For Further Reading

For further information please see the related pages below:

• Current transformer
• Transformer
• Electrical grid
• Distribution grid
• Connecting homes to the electrical grid
• Or explore a random page!