Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
Ask a Question or Search InspectAPedia
InspectAPedia ® Home
ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR
AFCIs ARC FAULT CIRCUIT INTERRUPTERS
ALUMINUM WIRING HAZARDS & REPAIRS
AMPS VOLTS DETERMINATION
APPLIANCE EFFICIENCY RATINGS
BOOKSTORE - ELECTRICAL
Cadet & Encore Heater Recall
CIRCUIT BREAKER SIZE for A/C or HEAT PUMP
Classified CIRCUIT BREAKER WARNING
CUTLER HAMMER PANEL FIRE
CORROSION in ELECTRICAL PANELS
DEFINITIONS of ELECTRICAL TERMS
DIRECTORY OF ELECTRICIANS
DMM Digital Multimeter, How to Use
ELECTRIC METERS & METER BASES
ELECTRIC MOTOR DIAGNOSTIC GUIDE
ELECTRIC MOTOR OVERLOAD RESET SWITCH
ELECTRIC PANEL AMPACITY
ELECTRIC PANEL INSPECTION
ELECTRIC PANEL MOISTURE
Electric Power Frequency Table
EMF RF FIELD & FREQUENCY DEFINITIONS
ELECTRICAL GROUND SYSTEM INSPECTION
ELECTRICAL SERVICE DROP
ELECTRICAL SERVICE ENTRY WIRING
EMF RF FIELD & FREQUENCY DEFINITIONS
FIRE SAFETY Checklist, CPSC
GFCI PROTECTION,Testing GFCIs AFCIs
HEATING COST FUEL & BTU Cost Table
HEAT TAPE USAGE GUIDE
Hertz - Definitions of KHz MHz GHz THz
KNOB & TUBE WIRING
LIGHTING, EXTERIOR GUIDE
LIGHTING, INTERIOR GUIDE
LIGHTNING PROTECTION SYSTEMS
LOW VOLTAGE BUILDING WIRING
LOW VOLTAGE TRANSFORMER TEST
MAIN DISCONNECT AMPACITY
MOISTURE SOURCES in PANELS
MURRAY SIEMENS Recall
PHOTOVOLTAIC POWER SYSTEMS
PUSHMATIC - BULLDOG PANELS
REMOTE ELECTRIC POWER, PHOTOVOLTAIC
RUST in ELECTRICAL PANELS
SAFETY for ELECTRICAL INSPECTORS
SE CABLE SIZES vs AMPS
SIEMENS MURRAY Recall
THERMAL EXPANSION of HOT WATER
THERMAL EXPANSION of MATERIALS
UNDERGROUND SERVICE LATERALS
VOLTS / AMPS MEASUREMENT EQUIP
WIND TURBINES & LIGHTNING
ZINSCO SYLVANIA ELECTRICAL PANELS
This electrical safety procedures article discusses safety hazards at residential electrical systems both outside and indoors, and suggests safety procedures for the electrical inspector, home inspector, or other professionals who examine residential electrical systems. Safe electrical inspection procedures and safe use of volt meters, DMMs, multimeters, and similar electrical test equipment is discussed at the end of the article.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Safety Suggestions for Electrical Inspectors: Electrical System Inspection Safety Procedures, Observations, Reports
ASHI Home Inspector Educational Seminar Proceedings: ASHI-NE Chapter Annual conference
This is the full text version. A powerpoint presentation version of this class is also available. Readers of this article should also see these other building inspection safety articles: Safety for Building Inspectors and Septic Inspection Safety and also STAIRS, RAILINGS, LANDINGS, RAMPS - INSPECTIONS, CODES
These electrical inspection suggestions are not a complete inventory of all electrical safety procedures nor of all electrical components that should be inspected; these notes focus on identification of conditions that may present special electrical hazards for the electrical inspector. Contact Us by email to suggest changes, corrections, and additions to this material.
Electric shocks are responsible for about 1,000 deaths in the United States each year, or about 1% of all accidental deaths.- Refs.
Fatal Shock Hazard Warning: Inspecting electrical components and systems risks death by electrocution as well as serious burns or other injuries to the inspector or to others. Do not attempt these tasks unless you are properly trained and equipped.
Homeowner advice for electrical panel safety: These safety suggestions are for professional inspectors and are not a guide for homeowners. Homeowners should not remove the cover from an electrical panel - it is unsafe to do so. Homeowners should look at their electrical equipment for signs of trouble and should contact a licensed electrician to address any concerns that arise. Without removing the electrical panel cover, but by opening the hinged electrical panel access door, homeowners can access the main circuit breaker or fuse, as well as individual circuit breakers and fuses. These devices may be turned on or off by the homeowner as safety or other needs require.
Reports of deaths during home inspections: ASHI, the American Society of Home Inspectors, has reported (to DF) a single death of an inspector while at work. A Canadian home inspector fell from an improperly installed steel ladder "affixed" to a multi-story building. That tragic death which was reported (by NY Metro ASHI News) in 1990.
Inspectors climbing in, on, around buildings should guard against becoming complacent, overconfident, or careless. ASHI Standards of Practice provide that an inspector may refuse to enter, inspect, access any component based on concern for safety. In our photo the inspector is pointing out how easily an inspector might touch live electrical components while also becoming grounded by a gas pipe.
Reports of injuries during home inspections: There have been reports of falls and fall-related injuries, reports of electric shock, reports of threats of violence, and one report of an attempted murder of a home inspector by a real estate agent. [SV to DF, New Paltz NY, re D.B. realtor, ca 1992].
As of September 2008, we have not heard reports of serious injuries to home inspectors or their clients during the inspection of electrical components. Electrical shocks, injuries, and fires certainly occur in residential as well as commercial environments.
Wet skin (standing in water, sweaty) has a resistance of about 1000 ohms. (Dry skin will have a higher resistance, and of course an inspector wearing protective gear such as rubber gloves, rubber-soled shoes, standing on an insulated mat, will have still higher electrical resistance, and safety.)
At this skin resistance, a current of only 0.1 to 0.3 amps at 100 Volts is sufficient to cause potentially fatal ventricular fibrillation. -- Wikipedia September 2008.
Portions of the ASHI Standards of Practice for home inspectors is commented upon below.
ASHI Standards and other building inspection standards are revised from time to time, and the version of Standards discussed here may be obsolete. However the principles discussed and cautions advised will apply to newer versions of building inspection standards as well.
ASHI is the American Society of Home Inspectors - see www.ashi.com. Other home inspection professional associations such as CREIA, NAHI, FABI, TAREI, CAHI, NACHI, and the various U.S. states who license home inspectors have published their own versions of these standards. Home inspection standards are a definition of the scope of practice - what the inspector is obligated to do or not do.
General Electrical Safety Suggestions describes important basic safety procedures, clothing, and equipment for home inspectors and electrical inspectors.
Pay special attention to water entry at the service entry cable, at the top of the electric meter enclosure, and at the wall penetration where the SEC enters the building as these conditions can send water into the electrical panel where corrosion creates unreliable equipment and water is a hazard.
See ELECTRIC METERS & METER BASES for procedures used for inspecting these outdoor components.
Details about inspecting electrical grounding and definitions are at ELECTRICAL GROUND SYSTEM INSPECTION.
8.3.C. [The inspector is NOT required to] dismantle any electrical device or control other than to remove the covers of the main and auxiliary distribution panels.
At least one death, that of an electrician, has been reported to have occurred during the removal of a panel cover
The following photos and text provide examples of external evidence that may let the inspector avoid trouble or a nasty surprise when inspecting electrical equipment.
The pair of photographs below show two clear warnings that water has been entering an electrical panel - watch out for rust, and for circuit breakers that may not trip in response to an overcurrent, due to internal corrosion.
This defect is not one for which a home inspector (nor most electricians) can reliably test in a home, but the warning remains appropriate. Replace such breakers, and if the electrical panel is badly corroded the entire panel needs replacement.
See RUST in ELECTRICAL PANELS for a detailed account of the sources of water and rust in electrical panels and the frequency of observation of rust and water damage in that equipment.
This distraction is more risky than it may appear. A sudden flash, a sudden shout or movement, could cause an inspector to lurch, touching an electrically live and dangerous component. It is important for the inspector to learn and practice calm, steady movements and to resist distractions.
How to Look for Unsafe Panel Cover Screws & for Evidence of Burning and Arcing When Approaching the Electrical Panel
The pair of photos just below shows at left, electrical arc flashover soot, and at right, the repair - tape on the electrical wire, but the wire is still too close to the screw mounting hole for the panel cover.
Now that we have removed the cover and carefully set the cover and screws aside (don't lose the screws),
8.3.B. [The inspector is NOT required to] test or operate any overcurrent device except Ground Fault Circuit Interrupters
8.1.D. [The inspector shall observe] branch circuit conductors, their overcurrent devices, and the compatibility of their ampacities and voltages
In addition to examining the electrical panel before touching it, looking for dangerous conditions like water, rust, sheet metal screws, rats, and blocking client access, the inspector should also recognize that certain brands or models of electrical equipment are known to be unsafe and may be dangerous to inspect or operate.
Federal Pacific Electric Stab-Lok equipment includes breakers which remain internally "on" when switched "off", as well as too often failing to trip off in response to an overcurrent, and which have been reported to result in electrical arc explosions when manually or otherwise exercised.
Zinsco: Similar bus burnups and electrical arc explosions have been reported regarding Sylvania/Zinsco electrical panels.
Contact Us by email to add field reports of problems regarding these or other electrical products.