Ground wire wrapped on water pipe (C) Daniel Friedman Local Electrical Grounding System Inspection Procedures & Safety
     

  • ELECTRICAL GROUND INSPECTION SAFETY - CONTENTS: How to inspect the electrical grounding system at a home: the grounding electrode, wiring, connections - Safety procedures during inspection of the electrical grounding system; Standards for Electrical System Inspections; How to use test equipment during electrical ground system inspections
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Electrical ground system inspection safety: 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.

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Inspect the Local Electrical Grounding Electrode or Grounding Connections - electrical ground system defects & safety hazards

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

Here we discuss safety considerations when inspecting the building electrical ground system. Readers of this article should also see ELECTRICAL GROUND SYSTEM INSPECTION - on how to inspect the electrical grounding system and what common defects may be present.

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.

  • 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 DOUBLE FAULT, LOSS OF ELECTRICITY 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.

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-ohm meter (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 DOUBLE FAULT, LOSS OF ELECTRICITY..

  • 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 DMMs VOMs SAFE USE OF.

Also see  Guide to Electrical Test Equipment and  DMMs VOMs SAFE USE OF as well as  ELECTRICAL INSPECTOR SAFETY PROCEDURES for building inspectors.

ELECTRICAL INSPECTOR SAFETY PROCEDURES 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

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.

 

Continue reading at ELECTRICAL GROUND REQUIREMENTS or select a topic from the More Reading links shown below.

Watch out: for safety, also review SAFETY HAZARDS & SAFE ELECTRICAL INSPECTION PROCEDURES for Inspectors examining Residential Electrical Systems and Local Electrical Grounding for safety procedures during inspection of the grounding system.

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ELECTRICAL GROUND INSPECTION SAFETY at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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