Although a home inspection is a relatively unregulated industry, professionals need to be mindful of their client’s safety. This awareness includes being aware of your surroundings. It can be difficult because every appointment changes. The most dangerous part of a home inspection is electrical, aside from walking on a roof. Many things can go wrong quickly, and some can prove fatal. Home inspectors need to be able to identify the causes of electrical shocks and arc flashes to avoid them.

The Basics

North American homes typically have a 120/240V split phase service. A pole-mounted distribution transformer provides this at the service drop. It is composed of two 120-volt lines as well as a neutral line. The triplex cable could also include a messenger wire located in the middle. This cable provides support for long distances. The earth ground is the neutral line that runs from the pole to the service panel. This earth ground is typically a conductive rod embedded into the earth. The service drop supplies the home with two 120 volt lines of opposite phases. 240 volts is possible by connecting a load to one of the 120-volt conductors. 120-volt loads can be connected to either the 120-volt or neutral lines. The circuit of 240 volts is for appliances that use substantial power, such as furnaces, dryers, washer and dryers, ovens, ranges, and water heaters. The 120-volt circuit can be used for smaller electrical loads such as household lighting and electronic devices that plug into standard electrical outlets or receptacles.

Three-phase power is used in Europe for homes. It has longer service drops and can supply power to multiple residences. This is a cost-effective way to provide power to dense areas. This service drop is composed of three-phase wires, and one grounded neutral.

How an Electrical Circuit Work?

It is possible to get an electric shock at any time that electrical power is present. This applies regardless of whether or not there are any protective devices.

An electrical circuit needs at least two wires to conduct electric current, which is in the form of electrons. The current is measured in amps. It travels from the power source (such a local utility), through the device that it operates (called the load), and back to the source to complete a circuit. AC wiring is alternating-current and has 120 volts in the “hot” wire. This voltage creates the momentum necessary for electrons to flow through the circuit. The hot side of an electrical device’s circuit is where the power switches are located. Because it is grounded at an electrical panel, the return conductor, also known as the neutral is at 0 V. Most 120-volt circuits are wired for 15 to 20 amps of current.

What Injuries Are Common?

Circuit breakers are used in modern electrical systems. Older constructions may have fuses. These devices are used to protect against over-current and are rated at amps. Most household circuits run on 15 to 20 amps. Over-current protection devices protect wiring and equipment from overheating. However, they do not protect people from electric shock.

A person can make a circuit by contacting a live load, or an energized wire. It is likely that an injury will occur if this happens. High-voltage exposure is the most common cause of fatalities. However, it is possible to sustain severe injuries from low-voltage power. Even though the current isn’t too high, it is possible for a person to be shocked or even electrocuted. A current of 50 to 100 milliamperes (1/1,000 of 1 ampere) can cause death.

Standards of Practice

The inspector does not have to:

• Measure or determine the voltage or amperage of the main service equipment.
• Remove dead fronts or panelboard cabinet covers;
• Insert any tool, probe, or device into the main panelboards, sub-panels or distribution panelboards.
• Any over-current protection or electrical disconnect device must be operated.

If they suspect a defect, inspectors can go beyond the SOP to give more information to their clients.

Warning Signs

However, there are signs that the system or panelboard may be compromised. These should prompt the inspector to refer the matter to an electrical contractor licensed to evaluate the situation.

• The scorch marks on the dead door or front panelboard indicate a recent or past arc flash.
• Rust is a sign of past or recent moisture intrusion
• Missing or open breakers, which cannot be confirmed to have been de-energized
• DIY wiring can overload circuits;
• Uninsulated wiring
• Excessive dust, dirt, and debris within the panelboard.
• Any signs of water around, under, or inside the panelboard can cause shock or electrocution.

What is an Arc Flash?

An arc flash is a flashover of electricity that travels through the air between one conductor or another. It can happen unexpectedly, can be quite explosive and short-lived, and it can also be very visually stunning. It can do some damage, or disable equipment and cause serious injury. Because it is unpredictable, an arc flash can cause serious injury. It will attract to any item that has the highest conductivity, such as a rodent, house pet, or person. An arc flash can result in serious electrocution or electrical burns.

Arc flashes can be triggered by a variety of catalysts, such as:

• excess dust;
• condensation;
• corrosion;
• component failure;
• Installation of a faulty system;
• Dropping a metal tool can cause sparks, and/or
• accidental contact.