The primary responsibility for a homeowner, when evaluating their electrical systems in the home, is the safety of himself and his family.
This is also one of the few areas which your home inspectors would report as a defect to some degree. However, without any knowledge, it's always highly encouraged to higher a professional to make any repairs or modifications. However, systems or components that were acceptable when the home was built a hundred or fifty years ago could now be considered defective. A lack of GFCIs in the kitchen, for example, would fall into this category.
Homeowners should be especially cautious when evaluating the service panels hence another name called a "Dead Front". An electrical system and distribution panel can kill anyone unfamiliar with the potential to cause great damage, harm, or death.
"According to the InterNACHI's Standards of Practice for Performing a General Home Inspection, a home inspector is not required to do anything that the inspector thinks is unsafe, including removing covers from electrical boxes or panels and exposing electrified, "live", or "hot" electrical components within."
Modern electrical systems are wired with circuit breakers, or with fuses in older construction. These devices serve as over-current protection and are rated in amps. Most household circuits are wired for 15 or 20 amps. Over-current protection devices are designed to protect the electrical system’s wiring and equipment from overheating, but they may not protect a person from electrical shock, which is why any type of component in the system should be approached with caution.
By coming into contact with a live load or energized wire, a person's body (even a finger) can complete a circuit by connecting the power source with the ground. If this happens, it’s likely that the person will sustain an injury. Most fatal injuries result from high-voltage exposure, but it’s possible to incur a severe injury from low-voltage power if it has a high-current flow. Even if the current isn’t high, a person could be shocked or even electrocuted without ever tripping a circuit breaker or blowing a fuse. Currents of 50 to 100 milliamperes (1 mA = 1/1,000 of 1 amp) can be fatal.
The typical electrical service for homes in North America is a 120/240V split-phase system provided by a pole-mounted distribution transformer located at the service drop, which is made up of two 120-volt lines and a neutral line. This triplex cable may include a messenger cable located in the middle of the neutral conductor that provides support over long spans. The neutral line from the pole is connected to an earth ground near the service panel, which is usually a conductive rod driven into the earth.
The service drop provides the home with two 120-volt lines of opposite phase, so 240 volts can be obtained by connecting a load between the two 120-volt conductors, while 120-volt loads are connected between either of the two 120-volt lines and the neutral line. The 240-volt circuit is used for a home’s electrical appliances that require substantial power, such as a furnace, water heater, air conditioner, washer and dryer, and oven/range. The 120-volt circuit is used for lighter electrical loads, such as household lighting, and portable appliances and electronics that are plugged into the home’s standard two- or three-prong (with a grounding wire) electrical receptacles or outlets.
A homeowner or your hired home inspector is not required to remove the dead front (the front cover) of any electrical panel or box. The image above is a panel cover. Removing it is hazardous. Most schooling that your home inspector would attend does NOT require and does NOT recommend home inspectors to remove the dead front (the front cover).
Inspectors should follow these basic safety rules when inspecting live electrical components:
Wear protective eyewear/protection.
Wear gloves. (NOTE: Gloves that have an energy rating professional gloves. Not some cheap hardware store $10 gloves...)
Do NOT wear nylon or polyester clothing.
Do NOT allow your child to get between you and any live components.
Visually inspect the panel or box without removing the dead front or cover.
Do NOT touch a panel or box that is either very rusted or shows signs of moisture.
Do NOT touch any panel or box that is buzzing or arcing.
Frequently test for stray voltage using a non-contact AC voltage tester.
Do NOT insert any probes or tools into electrical panels or boxes.
NEVER carry or position a ladder near an electrical line or cable.
If in any doubt about anyone's safety, defer any repairs to a licensed electrical contractor.