How does my electrical system work?

Your Home Electrical System

Electricity enters your home through a service head from a series of outdoor power lines or an underground connection.

A typical service head consists of two 220-volt wires and one neutral wire that deliver power to lights and appliances around the home.

Each year, 400 people are electrocuted in their own home or yard.

The electric meter is mounted outdoors where electricity enters your home.

This device is used to measure the amount of electricity that is consumed in your home.

The meter is monitored by your electric utility company and is protected by law—tampering with it is both extremely dangerous and illegal.

The service panel is the central distribution point for delivering electricity to switches, outlets, and appliances throughout the house. Located near the electric meter, the service panel is equipped with a breaker that shuts off power to the circuits if an electrical system failure occurs.

Groundin G is the method used to connect an electrical system to the earth with a wire.

Grounding adds critical protection against electric shock and electrocution by using a grounding rod to provide a third path for conducting electricity in the event of a short circuit or an overload.

Grounding will help protect the person working on the system, the system itself, and any appliances and equipment that are connected to the system.

We explain what electrical work you can do yourself.

What can you do?

There is a limited amount of electrical work you can do when it comes to wiring in your own home. This is listed in regulation 64 of the Electricity (safety) Regulations 2010 and includes:

Replacing switches, socket outlets, lamp holders, ceiling roses, water heater switches, thermostats and elements.

Repairing light fittings.

Moving, repairing or replacing flexible cords connected to permanently connected outlets or ceiling roses.

Disconnecting and reconnecting permanently wired appliances.

Moving switches, sockets and lighting outlets, but only if they are wired with tough plastic-sheathed cables.

Installing, extending, or altering any cables (except the main cables that come from the street to your switchboard).

You have to get the finished job checked and tested by a licensed electrical inspector.

You cannot connect your work to the electricity supply yourself.

The inspector will connect it, test it, and issue you with a Certificate of Compliance (see below) if it complies with safety requirements.

Fitting plugs, cord extension sockets or appliance connectors to a flexible cord.

Replacing fuse wires and fuse cartridges. Repairing appliances.

Before you do any work, make sure:

You have the necessary knowledge and skills.

The power is turned off.

You are not anywhere where conductors or terminals are live or could become live.

When something goes wrong

If you think something has gone wrong, make sure the power is off and contact a licensed electrician. Otherwise you risk injuring yourself or someone who lives with you and you could be prosecuted

There are training providers (like technical institutes) that run courses for people wanting to do their own electrical work at home.

For more information about working safely with electricity, contact the Energy Safety Service.

Work that must be done by a licensed electrician

Any work not appearing in the list above must be done by a licensed electrician. This is a person registered by the Electrical Workers Registration Board .

What's Inside My Service Panel?

Home Electrical Service Panel

Every home has a service panel that distributes electricity to switches, outlets, and appliances.

Service panels are equipped with fuses or circuit breakers that protect the wires in each circuit from overheating and causing a fire.

Older service panels use fuses, while more modern systems utilize circuit breakers.

A tripped breaker is likely the result of too many appliances overloading the circuit and should be fixed immediately.

Follow these steps to turn the power back on.

i n structions for r esettin G a tripped breaker Unplug or turn off appliances in the room.

Find your main breaker panel and open the cover.

Locate the tripped breaker or blown fuse. A tripped circuit breaker will be in the off position or in a middle position between on and off .

To reset the breaker switch it to off position and then back to on .

This may restore power to the room.

If the problem continues, there may be more serious issues.

Contact an electrician to diagnose the problem.

Fortunately, many of the dangers associated with older systems can be prevented simply by upgrading your home’s electrical service panel.

f uses Service panels installed before 1965 use fuses to protect each individual circuit. Once a fuse is blown, it must be unscrewed and thrown away.

Fuses were commonly used in 30- and 60-amp service panels. Today, most homes use 100- to 200-amp service. i n structions for r eplacin G fuses When replacing fuses in your service panel, the replacement fuse should always match the amperage rating of the circuit.

Never replace a fuse with one that has a larger amperage rating. This is a very dangerous practice.

What Kind Of Wiring System Is In My Home?

Understanding Your Home’s Wiring

More than 30 million homes, or about one-third of the homes in the United States are at least 50 years old, and studies have shown that the frequency of fires in these aging homes is disproportionately high.

Many older homes were built with electrical systems and components which are no longer safe and may be considered as fire hazards.

Electrical distribution systems are the third leading cause of home structure fires.

It is important to identify what type, color, and size wire is needed in order to properly address hazardous situations before they become critical.

Knob & Tube Wiring: 1800s–1930s Knob and tube wiring was designed as an open air system that used ceramic knobs to separate wires from combustible framing.

These suspended wires were directed through ceramic tubes to prevent contact with the wood framing and starting a fire.

Today, knob and tube wiring is considered a fire hazard because it is not a grounded system, and is more susceptible to damage from aging and faulty renovations.

Aluminum Wiring: 1960s–1970s

As the price of copper soared in the 1960s, it became common to replace copper wires with aluminum instead. Because aluminum is highly responsive to temperature fluctuations, it is more likely to become loose over time and lead to a highresistance connection that is a fire hazard.

It is estimated that nearly two million homes were wired with aluminum between 1962 and 1972.

If your home is equipped with aluminum wiring, consult an electrician about updating your wiring system and other options that can protect your home.

Grounded Electrical Systems: 1940s–Present

Electricity always seeks to return to its source and complete a continuous circuit.

A typical circuit in your home’s wiring system has two conductors—one that flows from the service panel to appliances in your home, and another that returns the current to the main service panel.

In a grounded electrical system, a third or “grounding” wire is connected to all outlets and metal boxes in your home, and is then connected directly to the earth using a metal grounding rod or a cold water pipe. In contrast, an ungrounded system does not prevent electricity from taking the path of least resistance – even if that path is through an unsuspecting person who comes into contact with an appliance that has a short circuit.

Grounding is a critical safety feature that protects you from shock or electrocution. If your home is not grounded, contact an electrician to upgrade your electrical system.