How to Inspect Residential Electrical Systems, Panels, Grounding, Wiring - Part 4 - the Service Ground InspectAPedia® -
List of defects in the electrical service ground system
How to inspect the electrical ground components at a building
Online Course on how to inspect electrical panels
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This article summarizes inspection of the electrical ground system at a building. Readers should see our complete electrical ground inspection information at ELECTRICAL GROUND SYSTEM INSPECTION. This document discusses procedures for safe and effective visual inspection of residential electrical systems including electrical panels and other components, when the inspection is conducted by trained building
inspection professionals, home inspectors, electrical inspectors, and electricians. It was presented by
Daniel Friedman - InspectApedia.com, at the Hudson Valley chapter of the American Society of Home Inspectors -
HVASHI Seminar 12 Sept 2002, Updated April 2006, April 2009.
Please see our complete article on the inspection & diagnosis of electrical grounding systems at ELECTRIC SERVICE GROUNDING.
Table of Electrical Ground Wire Sizes
Ground Gauge CU (Copper)
Service Size
#8
to 100A
#6
to 125A
#4
to 165A
4*
#3
to 200A
Electrical Service Grounding Defects & Conditions
not found in sub panel feeder (a)
attached to plastic pipe (b)
attached to abandoned pipe
(b)
spliced
(b)
loose or missing connections
(a) or (b)
inaccessible connections
no water meter bypass or other dielectric plumbing fitting bypass (bonding jumper)
local grounding electrode conductor not found in main panel
ground bond between neutral and ground and panel enclosure not found in the main panel
no water meter/water shutoff valve bypass (bonding jumper) (a)
neutral (the grounded conductor) bonded to ground downstream of box (or upstream)
neutral bus not bonded to the ground bus (equipment grounding conductors & ground bus) at main panel
main panel not bonded to grounding electrode conductor and ground bus
undersized grounding electrode conductor wire
ground rod (grounding electrodes) cut off or short (or only one grounding electrode connection at new construction)(b)
corroded grounding electrode conductor (b) - More about the galvanic scale and corrosion between dissimilar metals is at GALVANIC SCALE & METAL CORROSION.
loose or missing grounding electrode conductor clamp at the grounding electrode (b)
loose or missing bonding jumper clamp(s) such as at a water meter or water pipe (b)
bare aluminum grounding electrode conductor
exposed to corrosion (b) - More about the galvanic scale and corrosion between dissimilar metals is at GALVANIC SCALE & METAL CORROSION.
neutral bonded to the equipment grounding conductor (the ground wire) in sub panel or junction box (a)
neutral not bonded to ground at the main service panel (b)
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Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Recommended books on electrical inspection, electrical wiring, electrical problem diagnosis, and electrical repair can be found in the Electrical Books section of the InspectAPedia Bookstore. (courtesy of Amazon.com)
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.
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.
"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.
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