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ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR
AFCIs ARC FAULT CIRCUIT INTERRUPTERS
ALUMINUM SECs & WIRING
ALUMINUM WIRING HAZARDS
AMPS & VOLTS DETERMINATION
CIRCUIT BREAKER FAILURE
Classified CIRCUIT BREAKER WARNING
DEFINITIONS of ELECTRICAL TERMS
DIRECTORY OF ELECTRICIANS
ELECTRIC METERS & METER BASES
AMPACITY - the LIMITING FACTOR
ELECTRIC PANEL AMPACITY
ELECTRIC PANEL INSPECTION
ELECTRICAL BASICS
FEDERAL PACIFIC FPE HAZARDS
GROUND SYSTEM INSPECTION
KNOB & TUBE WIRING
LIGHTNING PROTECTION
LOW VOLTAGE BUILDING WIRING
MAIN DISCONNECT AMPACITY
MULTI-WIRE CIRCUITS
RUST in ELECTRICAL PANELS
SAFETY: ELECTRICAL INSPECTION SAFETY
  Shock Risk Statistics
  Outside Electrical Inspection
  Electric Meter & Service Entry
  Local Electrical Grounding
  Electrical Panel Interior Inspection
  Removing Electric Panel Covers
  Electrical Panel Cover Screws
  Electrical Panel Interior Hazards
  Testing Main Breakers or Fuses
  Inspect Breakers, Fuses, Circuits
  Testing Receptacles GFCIs AFCIs
  When to Shut Down Equipment
  Touching Electrical Equipment
  Guide to Electrical Test Equipment
  Using DMMs & VOMs Safely
  Voltage Measurement & Detection
  General Electrical Safety Suggestions
  Electrical Inspection Client Safety
SE CABLE SIZES vs AMPS
SQUARE-D RECALLS
UNDERGROUND SERVICE LATERALS
VOLTAGE MEASUREMENT EQUIPMENT
ZINSCO / SYLVANIA HAZARDS

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Ground wire wrapped on water pipe (C) Daniel Friedman

Electrical Safety Hazards and Safe Electrical Inspection Procedures for Electrical Inspectors & Home Inspectors
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  • Safety procedures during inspection of the electrical grounding system
  • Standards for Electrical System Inspections
  • How to use test equipment during electrical inspections
Our site offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at inspect-ny.com/appointment.htm.

This article discusses safety suggestions when inspecting the grounding system at residential electrical systems 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.

Readers of this article should also see GROUND SYSTEM INSPECTION - on how to inspect the electrical grounding system and what common defects may be present.

© Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

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.

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.

Inspect the Local Electrical Grounding Electrode or Grounding Connections

Ground wire wrapped on water pipe (C) Daniel Friedman Loose ground at water pipe (C) Daniel Friedman

  • Do not assume that the grounding electrode is a real one. Kick it. We find short scraps driven into the ground that can sometimes just be pushed over or pulled out, as our client is demonstrating. Often ground connections have come loose, were never connected, or have corroded away. The ground connection shown here is not reliable. The inspector has easily lifted the short ground rod out of the ground. (Photo above left)
  • Do not assume that the utility company's ground (back at the pole) is connected and working. Sometimes that ground has been lost and only the local ground is present - a very dangerous condition. See Case History: Double Fault Leads to Loss of Power for an account of loss of both local ground and utility company ground at a property.
  • Do not assume that water pipes form a good ground - original metal pipes extending into the soil may have been replaced with plastic. (Photo above right)
  • Do not assume that grounding connections you see are actually secure and making good electrical contact.

Details about inspecting electrical grounding and definitions are at GROUND SYSTEM INSPECTION.

electrical inspectors.

Using a Neon Tester, a DMM or VOM to Check Grounding Connections

VOM in use measuring live voltage (C) Daniel Friedman A simple volt ohm meter volt-ohmeter (VOM) such as the TriplettTM 310 or our little mini digital multimeter (DMM) shown at left can be used to test for unexpected and unsafe voltage at a component.

Testing for live voltage: this procedure describes a method for checking for the presence of live voltage.

During electrical work when we want to know if a metal part is connected to the grounded conductor (neutral) or to ground, we might use a neon tester to create a connection between a point of live voltage and the item which is being tested for grounding.

Be careful: this is not a reliable nor a complete test. For example, a weakly-grounded wire or electrode may look just fine when tested with a VOM, a DMM, or a neon tester, but when subject to higher current flow the ground may be completely inadequate.

For a case study which found exactly this problem, see Case History: Double Fault Leads to Loss of Power..

 

  • Never touch metal plumbing or gas system pipes while you're working around electricity.
  • Never touch electrical equipment while standing on a damp or wet surface. [Unless you are trained and are wearing appropriate protective gear.]

For example, if the meter indicates more than 1or 2 volts between a service panel cover and ground, there's a safety problem. Most low-cost analog-type meters such as the one described provide additional ranges used to read lower voltages with more sensitivity.

Some VOM models provide alligator clips for the ends of the test probes. These clips permit measuring high voltage without handling the probes. Always shut off the power before connecting the alligator clips.

Details on safe use of DMM's and VOMs are at Using DMMs & VOMs Safely.

Also see  Guide to Electrical Test Equipment and  Using DMMs & VOMs Safely as well as  General Electrical Safety Suggestions for building inspectors.

General Electrical Safety Suggestions describes important basic safety procedures, clothing, and equipment for home inspectors and electrical inspectors.

These electrical inspection suggestions are not a complete inventory 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

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

SAFETY: ELECTRICAL INSPECTION SAFETY
  Shock Risk Statistics
  Outside Electrical Inspection
  Electric Meter & Service Entry
  Local Electrical Grounding
  Electrical Panel Interior Inspection
  Removing Electric Panel Covers
  Electrical Panel Cover Screws
  Electrical Panel Interior Hazards
  Testing Main Breakers or Fuses
  Inspect Breakers, Fuses, Circuits
  Testing Receptacles GFCIs AFCIs
  When to Shut Down Equipment
  Touching Electrical Equipment
  Guide to Electrical Test Equipment
  Using DMMs & VOMs Safely
  Voltage Measurement & Detection
  General Electrical Safety Suggestions

Handling Immediate Threats to Life and Safety at a Building Inspection

If in the inspector's judgment equipment is an immediate threat to life and property, such as a boiler whose flue connection has fallen off, we recommend that dangerous equipment be shut down and the appropriate people notified. See Shutting Down Unsafe Equipment. In some cases "appropriate people" includes not only the client and building owner, but also building occupants.

In some instances such as sparking electrical panels, gas leaks, or evidence of a fire, the inspector and everyone else should leave the building immediately and from outside, call the fire department and as appropriate, the gas company, police, or rescue personnel.

Technical Reviewers & References

Particular thanks are due to experts and also consumers who read these articles and suggest corrections, changes, and additions to the material. Content suggestions, technical corrections and content critique are invited for any of the content at our website.

  • Daniel Friedman - principal author/editor of the InspectAPedia TM Website
  • Electrical shock injury statistics: www.healthatoz.com - September 2008;
  • Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
  • "Frequency of Occurrence and Sources of Rust and Corrosion in Electrical Panels," Daniel Friedman, IEEE HOLM Conference, Philadelphia PA, 1992 - see ELECTRIC PANEL RUST for an online version of this article.
  • Jim Simmons: Personal communication, J. Simmons to Daniel Friedman, 9/19/2008. Photographs contributed to this website by Jim P. Simmons, Licensed Electrician, 360-705-4225 Mr. Electric, Licensed Master Electrician, Olympia, Washington Contact Jim P. Simmons, Licensed Master Electrician, Mr. Electric, 1320 Dayton Street SE
    Olympia, WA 98501, Ph 360-705-4225, Fx 360-705-0130 mrelectricoly@msn.com
  • Kenneth Kruger: Original author of the sidebar on testing VOM DMM condition: Kenneth Kruger, R.A., P.E. AIA ASCE, is an ASHI Member and ASHI Director in Cambridge, MA. He provided basis for this article penned by DJ Friedman.
  • "How to Use DMM's Safely," Leonard Ogden, CEE News, 888 Seventh Ave., New York, NY 10106, Dec 1990 p.10.
  • Dr. Jess Aronstein, consulting engineer, Poughkeepsie NY, 1991 protune@aol.com
  • Rex Cauldwell, master electrician and contributor to the Journal of Light Construction on electrical topics
  • New York State Central Hudson Gas and Electric Company, G&E/1-2/85 consumer safety pamphlet
  • American Society of Home Inspectors, ASHI Training Manual, Al Alk -[obsolete, and includes unsafe practices-DF]
  • Critique, contributions wanted: Contact Us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

More expert information on this topic



ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR
AFCIs ARC FAULT CIRCUIT INTERRUPTERS
ALUMINUM SECs & WIRING
ALUMINUM WIRING HAZARDS
AMPS & VOLTS DETERMINATION
CIRCUIT BREAKER FAILURE
Classified CIRCUIT BREAKER WARNING
DEFINITIONS of ELECTRICAL TERMS
DIRECTORY OF ELECTRICIANS
ELECTRIC METERS & METER BASES
AMPACITY - the LIMITING FACTOR
ELECTRIC PANEL AMPACITY
ELECTRIC PANEL INSPECTION
ELECTRICAL BASICS
FEDERAL PACIFIC FPE HAZARDS
GROUND SYSTEM INSPECTION
KNOB & TUBE WIRING
LIGHTNING PROTECTION
LOW VOLTAGE BUILDING WIRING
MAIN DISCONNECT AMPACITY
MULTI-WIRE CIRCUITS
RUST in ELECTRICAL PANELS
SAFETY: ELECTRICAL INSPECTION SAFETY
SE CABLE SIZES vs AMPS
SQUARE-D RECALLS
UNDERGROUND SERVICE LATERALS
VOLTAGE MEASUREMENT EQUIPMENT
ZINSCO / SYLVANIA HAZARDS
More Information

InspectAPedia ® Home & Site Map
Air Conditioning
InspectAPedia Bookstore
Electrical
Environment
Exteriors
Heating
Home Inspection
Insulate Ventilate
Interiors
Mold Inspect/Test
Plumbing Water Septic
Roofing
Structure
Accuracy & Bias Pledge
Contact Us

More Information on Electrical Inspection Procedures, Electrical Hazards, Building Diagnostic Inspections and Repairs

  • * Safety Hazards and Safe Inspection Procedures for Electrical and Home Inspectors at Residential Electric Panels
  • Aluminum Wiring Information Website Aluminum Electrical Wiring Hazards and Repairs: in-depth authoritative info, photos, documents including selection of proper vs. ineffective repair methods. E.g.: Ideal 65 "Twister" purple connector fails in field and lab testing with aluminum wire.
  • Ampacity of an Electrical Service: How to determine the electrical service size or ampacity entering a building
  • Circuit Breaker, a bad one fails to trip failure at aluminum bus-to-circuit breaker connection - field report and photographs
  • Electrical Panels, How to Inspect in Buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects, defective products. Inspection Class Presentation
  • Federal Pacific Electric (FPE) Stab-Lok Circuit Breaker Panel Hazards Website - Latent fire hazards, in-depth authoritative research, documents, advice on Stab-Lok electric panel and circuit breaker failures and what to do when this equipment is found in buildings.
  • Lightning Strike Risk Assessment, Protection Systems & Services
  • Multi-wire branch circuit inspection and defects
  • Rust and Corrosion in Electrical Panels, A Study and Report on Frequency and Cause for Electrical and Home Inspectors at Residential Electric Panels
  • "Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
  • "Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
  • "How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
  • "Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
  • "Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
  • "How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
  • "Home Wiring Inspection," Roswell W. Ard, Rodale's New Shelter, July/August, 1985 p. 35-40.
  • "Evaluating Wiring in Older Minnesota Homes," Agricultural Extension Service, University of Minnesota, St. Paul, Minnesota 55108.
  • "Electrical Systems," A Training Manual for Home Inspectors, Alfred L. Alk, American Society of Home Inspectors (ASHI), 1987, available from ASHI. [DF NOTE: I do NOT recommend this obsolete publication, though it was cited in the original Journal article as it contains unsafe inaccuracies]
  • "Basic Housing Inspection," US DHEW, S352.75 U48, p.144, out of print, but is available in most state libraries.
  • Electrical System & Wiring Hazard Inspection, Detection, Cause, Remedy, Prevention - Main Electrical Page
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