Investigation Guideline

Investigation Guideline
Product:
Appendix # :
Date amended:
I.

Electrocution / Electric Shock
34
November 4, 2003

Introduction
A. Background Information
In 2000, out of the estimated 400 electrocutions that occurred nationwide, about
150 (38%) involved consumer products. In-depth incident investigations will
provide up-to-date information on the impact of current technological interventions
that may prevent shock, help to identify whether and how safety features are being
circumvented or omitted, as well as identify products that do not meet current
voluntary standards.
Electric shock or electrocution can only occur when a person simultaneously
touches two conductive surfaces that are at different voltage levels. One of the
surfaces could be near zero volts or ground voltage such as water pipes, wet/damp
soil or concrete floor, electrical conduits or boxes, the metal cabinet of a major
appliance or metal-housed tool. If the voltage difference is high enough (generally
exceeding 30 volts AC) and the resistance is low enough, an electrical current
flows and the victim experiences a range of sensations or physiological responses.
Most people feel a slight tingling at about 1/1000 Ampere (1 milliampere)* . At ten
times higher currents (1/100 Ampere or 10 milliamperes), the shock becomes
painful and a victim's muscles begin to contract uncontrollably. A man holding
onto an electrically charged power drill may not be able to let go of the tool.
When the shock current reaches 100 milliamperes (1/10 Ampere)** and lasts for
several seconds, the human heart may go into "ventricular fibrillation." The
victim's heart, beating weakly and erratically, is unable to circulate oxygenated
blood to the brain, and death can occur within minutes unless circulation resumes
with rescue CPR (cardiopulmonary resuscitation) or the heart is restarted using an
electronic defibrillator.
Modern household wiring systems incorporate 3-wire grounded branch circuits
employing a separate grounding wire that attaches to the receptacle's yoke (frame)
and to the outlet box. If it is equipped with a 3-wire cord and a plug having a

*

One milliampere results if 30 volts are applied across a resistance of 30,000 ohms, which is the resistance
of a dry finger tip touching a heavy copper wire.
**
One-tenth ampere results from 120 volts applied across a 1200 ohm resistance, which is equivalent to a
sweaty hand grasping an electric drill's metal handle.

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round ground pin, an electrical appliance's metal housing will be connected to
ground when the cord is plugged into a properly installed 3-wire receptacle. The
ground wire supplies a path for fault current in case an internal short-circuit in an
appliance connects the ungrounded, normally energized portion of the product
wiring to its housing. Typically this fault current will be enough to activate a
circuit protection device (fuse or circuit breaker) and disconnect power from the
appliance. If the ground wire is missing or the ground pin is broken off the plug or
the receptacle is miswired, that protection disappears. Not only is fire from shortcircuit overheating a possibility, but severe electrical shock or electrocution is
likely when someone touches the appliance.
Older homes may have only 2-wire circuits or receptacles and lack the protection
provided by appliance grounding. Residents of older homes sometimes try to use
appliances with 3-wire cords and plugs in two wire receptacles by installing "3wire adapters." These adapters have a pigtail wire or terminal that must be
connected to a ground screw, usually assumed to be the center screw on a
receptacle cover plate. Sometimes the "Hot" and "Neutral" connections are
reversed when an adapter is utilized, or the pigtail or terminal is left unconnected,
or the center screw does not connect to a grounding circuit. Any of these instances
increases the risk of dangerous, potentially fatal electrical shock.
Better protection from electrocution is provided by a Ground Fault Circuit
Interrupter, or GFCI. A correctly installed, working GFCI can detect minute (6
milliampere) imbalances in current flow into and out of an appliance circuit and
disconnect the voltage to protect against serious injury. GFCIs can even be
installed when a ground wire is not available, but the NEC (National Electrical
Code) requires that the receptacle be specially marked to show that the ground is
missing. GFCIs provide the best protection against injury from electrical shock.
Some people buy "double insulated" tools to have increased protection from
electrical shock. The tools are specially marked to show that they have an extra
amount of protective insulation beyond the usual coating on wires and electrical
components. While the extra insulation can be effective against internal wiring
insulation faults, it can be compromised if the tool gets wet or when rough use
damages even the extra insulation.
CPSC's data and analyses of electrical shock incidents1 show that electrical
products and systems have become better over the years. Still, we find incidents
where a manufacturer did not understand or apply safety technology properly or
where some person(s) created a situation by working improperly on a product or
system that ultimately caused the injury or death. CPSC's continued investigation
of shock incidents will help to identify root causes of increased risks of injury or
death and, perhaps, to develop and propose workable solutions.

1

See section V, item A, on page 7.

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In addition to filling out the Data Record Sheet (DRS) attached to the end of this
document, please provide any relevant information that is discovered in the
investigation process that may not have been specifically requested in this
guideline or the DRS.

B. Product Class Description
We are interested in any consumer product involved in an electrocution or electric
shock. If a product-specific guideline exists, please follow the instructions in that
guideline in conjunction with this electric shock guidance.
For incidents involving contact with power line, use the guideline on “Outdoor
Communications Antennas and Other Products", Appendix # 1.
C. Specific Items of Interest
Whenever possible, please include diagrams. We are particularly interested in
obtaining information to assist in evaluating the effectiveness of:
a. Grounding circuits
b. Double insulation
c. Over-current protective devices (fuses or circuit breakers)
d. Ground fault circuit interrupters (GFCIs)
D. Headquarters Contacts
1. Doug Lee, ESEE, 301-504-7569, [email protected]
2. Richard Stern, CRC, 301 504-7620, [email protected]
3. Risana Chowdhury, EPHA, 301-504-7334, [email protected]

II.

Instructions for Collecting Specific Information
A. Synopsis
In the synopsis of the report, please use the keywords electrocution, electric
shock, or GFCI as appropriate, to ease the computer-based data retrieval process.
Also use the appropriate product code for the product primarily responsible for the
shock.
• Try to include in the narrative a description of the circumstances that led up to
the incident. Was an appliance or power cord damaged to expose electrically live
conductors? Did an electrical product come into contact with or become immersed
in water? Did someone assemble or rewire an electrical cord or appliance or
perform work on a household wiring circuit?

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• Describe in the narrative how the incident happened with supporting facts. What
was the victim doing? How was contact with electricity made? Was the victim
using protective equipment or clothing (gloves, boots, etc.--provide descriptions)?
What else was being used? Who discovered the incident? How? What did they do?
• Describe in the narrative the deaths, injuries, type of treatment administered, and
extent of any property damage. Describe the current condition of the product in
question.

B. Description of Incident Environment
Describe the accident scenario with as much detail as available. In particular, try
to identify grounding paths and possible source(s) of stray current. Describe
whether water, moisture, or dampness might have been involved in aggravating the
severity of the incident.
Definition: "Grounding Path"
A grounding path is the route that electric current takes to return to the
lower voltage side of its source. Current always takes a path from the higher
voltage component of a source of electrical energy through conductive material,
like copper wire, or resistive material, like damp ground, to the lower voltage
component of the source.
The low voltage side of all residential and commercial AC electrical
systems is required to be connected to "Earth Ground", usually through a metal
rod or copper pipe buried in the ground. So the return path for AC current is often
called the "grounding path."
Definition: "Stray Current"
In a "normal" electrical circuit, the current flows only in the conductors,
i.e., the wires, motor windings, lamp filaments, and other electronic components of
the appliance, power cord and household wiring that supply the appliance.
If a person or some object that can conduct electrical current comes into
contact with an energized (voltage-carrying) conductor, some of the current may
"stray" from its normal path and flow through the person or object. Current will
flow if the person or object is simultaneously in contact with a grounding path to a
lower voltage. The amount of stray current that flows depends on the total
resistance of the new path.
Sometimes the source of stray current is not obvious, such as when a faulty
underwater light or a fallen extension cord in a pool energizes the water.
Someone standing, barefooted, at the side of the pool who reaches into the water
may be severely shocked.

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C. Description of Victim's Contact with Product
•Describe victim's posture/condition (moist skin, fully clothed vs. bare arms, legs,
or feet, sitting or standing on ground, etc.) at the onset of the incident.
•Determine, as well as possible, victim's experience with, or knowledge of product
(e.g., whether victim had read and understood instructions or operator's manual,
was aware of the safety devices or features, or was aware of potential hazards).
•Specify victim's point of contact with the product and grounding surface and the
body part(s) involved (e.g., hand touching a knob on the product while a bare knee
was in contact with a metal pipe, etc.). Describe the clothing and its condition if it
was directly involved in the incident (e.g., work gloves, hat, or boots that touched
the voltage source or ground path).
State the source of the above information (such as victim, witness, investigative
report, etc.).

D. Description of Product
•Specify product characteristics and labeled ratings, such as BTU rating,
size/capacity, volts/amps/watts, testing laboratory certifications (UL, ETL, or
CSA, for example), CE markings, or indications of conformance with specific
standards, and any other descriptive information or symbols on rating plate, etc.
•Whenever available, list manufacturer's name, brand name, model/serial number,
date of manufacture and lot number, age of product (date of purchase or
acquisition, if possible) and any markings or date-codes from which product
information might be gained. Record a description of the condition of the product
at the time of acquisition (new, used, reconditioned, other, specify).
•Provide wording of any warning/safety instruction labels affixed, and describe the
shape and color of any symbols shown on them.
•Provide as much detailed information as available about:
a. Grounding circuits - Describe branch wiring that provided power (2-wire, 3wire, type and gauge of wire, receptacles grounded or not, HOT and
NEUTRAL connections properly polarized). Describe condition of extension
cords or accessory cords and wiring that were used, including number of wires,
presence or absence of ground pins on plugs, repairs, polarization of wires, etc.
Describe condition of power cord(s) on product(s).

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b. Double insulation - Describe materials used on product enclosure, housing or
case. Identify any label references to insulation systems, including specific
wording, such as "Double Insulated," or "square-inside-a-square" symbol.
c. Over-current protective devices (fuses or circuit breakers) - Describe location,
type and condition of fuse-box or panel-board. Describe type and condition of
fuses and circuit breakers. Attempt to determine whether they are in working
condition or whether they have been bypassed in some way. Try to determine
when they were most recently replaced, exercised (turned on and off several
times) or tested. Identify any GFCIs or AFCIs (arc-fault circuit interrupters) by
brand, model, type, ratings, etc.
d. Ground fault circuit interrupters (GFCIs) - Describe location, type (breaker,
receptacle, portable, etc.), brand/model, ratings, and condition of any GFCIs
found that may have been involved with incident. Attempt to determine when
GFCI was installed, how often it was tested, and when it was most recently
tested. DO NOT ATTEMPT TO TEST OR RESET the GFCI or otherwise
alter its state. Attempt to determine if an installed receptacle-type GFCI is
correctly wired into its circuit (LINE and LOAD or HOT and NEUTRAL not
reversed). Seek the services of a licensed electrician if necessary.

III.

Photographs/ Diagrams of Incident Scene
A diagram or photograph of installation is particularly useful. Good photographs
of the product and/or the incident scene are always helpful.

IV.

Obtaining samples and documents related to the investigation
•Collect sample(s) if available, keeping the sample(s) as undisturbed as possible. If
no sample is present, describe similar products at the incident site. Record
observation of their appearance compared to the failed unit.
•Collect any extension or accessory cords involved in the shock incident.
•The GFCI should be collected if it was in the circuit that supplied shock current.
If there are competing interests for the GFCI or other product samples, contact the
CPSC Compliance Officer for guidance. Attempt to negotiate for possession or to
gain written assurance from an official having proper jurisdiction that a report of
analysis will be delivered to you. Examination of possibly non-functioning GFCIs
should be conducted by a competent forensic investigator who is an expert in
failure analysis of electronic power-handling devices. Refer to the CPSC
Investigation Guideline on "15- and 20-ampere Electrical Receptacles” for
recommendations on collection methods involving receptacles.

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•Obtain copies of reports and photographs from repair facility or insurance
company.
•Include copies of any installation instructions, user manuals, or product safety
information inserts.

V.

Additional information on electrocution and electrical safety
A. An Evaluation of the U.S. Consumer Product Safety Commission’s
Electrocution Reduction Program, November 2002, Robert Garrett, Susan B.
Kyle, Ph.D., Office of Planning and Evaluation. PDF document available in two
parts at:
http://www.cpsc.gov/LIBRARY/FOIA/FOIA03/os/Electropt1.pdf and
http://www.cpsc.gov/LIBRARY/FOIA/FOIA03/os/Electropt2.pdf
B. Lessons in Electrical Circuits, Vol. I, Ch. 3, "Electrical Safety," web-published
2000-2003, Tony R. Kuphaldt at:
http://www.ibiblio.org/obp/electricCircuits/DC/DC_3.html
C. Electrical Safety--Safety and Health for Electrical Trades, DHHS (NIOSH)
Publication No. 2002-123 at http://www.cdc.gov/niosh/docs/2002-123/2002123a.html

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DATA RECORD SHEET
Investigation Guideline
PRODUCT: Electric Shock / Electrocution
s
s
TASK NUMBER __________________________
INCIDENT DATE ___________________________

A. Product / Accessories
1.

Product Code_____________________________________________________

2.

Product Name ____________________________________________________

3.

Label Ratings: _________Volts AC? or DC? (circle choices)
________ Amps
________Watts or volt-amperes (VA)

4.

Describe and/or photograph any warning labels on the product.(Present?) (None?)

5.

UL, CSA, or other agency mark _______________________________________

6.

Manufacturer ______________________________________________________

7.

Model Name/Number _______________________________________________

8.

Serial Number _____________________________________________________

9.

Age of appliance ___________________________________________________

10.

Purchased (NEW?) or (USED?) Date: _________________________________

11.

What was the appliance cord like?
11.1. Permanently connected? _____________ Or Removable? ____________

11.2. What markings are on the cord?__________________________________
________________________________________________________________________
11.3. What markings are on the plug body or the prongs? __________________
________________________________________________________________________
12.

What was appliance plug like (Use Table with NEMA configurations on page 13)?
12.1.
Two-pronged (NEMA 1-15P)? YES NO
•
Polarized (different sizes for prongs) YES NO

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13.

12.2.

Three-pronged (NEMA 5-15P, for example) YES NO
•
Type? _________
•
Are all prongs present? YES NO
•
If not, which one is missing? (Make sketch if necessary)

12.3.

GFCI or ALCI (Appliance Leakage Circuit Interrupter, 2-blade) on the
plug? (Usually has "TEST" and "RESET" button on plug body.) YES NO

12.4.

Was a 2-blade-to-3-blade grounding adapter used? If so, describe or sketch
adapter. _______________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________

What was the receptacle like? (Use Table with NEMA configurations on page 13)
13.1.
2 slots (like NEMA 1-15R)? YES NO
•Polarized? YES NO
•GFCI present in circuit breaker panel? YES NO
•GFCI label on receptacle? YES NO (required if GFCI breaker)
13.2

3 Slots (NEMA 5-15R or others, for example)
•Type? ___________________
•GFCI present in receptacle or in circuit breaker panel?

14.

What was the condition of the product before the incident?
14.1.
Cord _______________________________________________________
__________________________________________________________________
__________________________________________________________________
14.2.
Plug _______________________________________________________
__________________________________________________________________
__________________________________________________________________
14.3.
Appliance ___________________________________________________
__________________________________________________________________
__________________________________________________________________
14.4.
Any attachments or accessories __________________________________
__________________________________________________________________
__________________________________________________________________

15.

Was an extension cord used? Please describe the cord and any markings on it.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________

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16.

What, if any, repairs or maintenance were made to the appliance, cords, or accessories
prior to the incident date? ________________________________________________
________________________________________________________________________
17.
Were any evaluations performed by police, fire, medical examiners, independent
investigators, etc. on the appliance, cords, or accessories following the incident?
(Obtain copies of any evaluation reports.)_____________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
18.
Are the gripping surfaces of the product metal or insulated? _____________________
________________________________________________________________________
________________________________________________________________________
19.
Did the product shock anyone before? If so, describe any differences between that
incident and this incident (location, user, extension cords, weather, etc.). ___________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________

B. Power Source
20.

Did the incident cause any circuit breakers or other protective devices to activate?
What are the voltage and current ratings of the protective devices? ________________
________________________________________________________________________
________________________________________________________________________
21.
Describe any visible changes to the appliance after the incident (smoked areas,
blackened areas, melting, etc.)? ____________________________________________
________________________________________________________________________
________________________________________________________________________
22.
If you have an electrical tester (SureTest® or equivalent), what are the results of the
receptacle test? ________________________________________________________
________________________________________________________________________

C. Victim
23.

Who was using the appliance? ________________________________________
________________________________________________________________________
_______________________________________________________________________
24.
How much experience did the victim have with this and similar appliances/tools?
________________________________________________________________________
24.1.
Did the intended task differ from previous tasks done by the victim?
__________________________________________________________________
__________________________________________________________________
24.2.
How long did it normally take the victim to perform the task involved and
how long did the task take when the victim suffered the shock?
__________________________________________________________________
__________________________________________________________________

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25.

Who else has used the appliance? __________________________________________
________________________________________________________________________
________________________________________________________________________

26.

Did anyone notice any unusual operating characteristics of the appliance?
________________________________________________________________________
________________________________________________________________________
27.
Describe what the victim was wearing. _____________________________________
________________________________________________________________________
________________________________________________________________________
28.
Specify if the victim’s body was wet or sweaty. ______________________________
________________________________________________________________________
________________________________________________________________________

D. Circumstances
29.

Weather conditions at time of incident
29.1.
Temperature _________________________________________________
29.2.

Humidity ___________________________________________________

30.

Was water involved? How and where? _____________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
31.
Were other live electrical circuits involved (e.g. saw cut through a power cord, tiller
hit buried wire, drill cut into household wiring, etc.)? _________________________
________________________________________________________________________
________________________________________________________________________
32.
If possible, specify the victim’s point of contact with the product where the shock
occurred and with the surface that provided a path to ground (or to a different voltage
level). ________________________________________________________
________________________________________________________________________
________________________________________________________________________
E.

ADDITIONAL NOTES and INFORMATION
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________

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________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
F. SKETCHES

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(NOTE: 3-pole (3-phase) plugs and receptacles are not likely to be in homes, but
heavy stove, heater and air conditioner circuits may use 3-poles, 3 or 4 wires)

TABLE -- NEMA (National Electrical Manufacturers Association) Plug and Receptacle
Configurations (for use as reference to answer Q12 and Q13 on DRS)