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U. S. Department of Labor
Occupational Safety and Health
Administration
Directorate of Science, Technology and Medicine
Office of
Science and Technology Assessment
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Hazards of Improper Elevator Controller Wiring
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Safety and Health Information Bulletins |
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SHIB 08-16-2004 |
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This Safety and Health Information Bulletin is
not a standard or regulation, and it creates no
new legal obligations. The Bulletin is advisory in
nature, informational in content, and is intended
to assist employers in providing a safe and
healthful workplace. The Occupational Safety
and Health Act requires employers to comply
with hazard-specific safety and health standards.
In addition, pursuant to Section 5(a)(1), the
General Duty Clause of the Act, employers must
provide their employees with a workplace free
from recognized hazards likely to cause death or
serious physical harm. Employers can be cited
for violating the General Duty Clause if there is a
recognized hazard and they do not take reasonable
steps to prevent or abate the hazard. However,
failure to implement any recommendations
in this Safety and Health Information Bulletin is
not, in itself, a violation of the General Duty
Clause. Citations can only be based on standards,
regulations, and the General Duty Clause.
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Preface
An employee was fatally injured when the
elevator he was entering continued to move while the
elevator doors were open. An investigation revealed
that the interlock, which would have prevented
movement of the elevator car with the doors in the
open position, had been bypassed due to improper
wiring. This incident highlights the importance of
elevator maintenance and repair adhering to
manufacturer design codes and applicable industry
safety procedures and standards.
Purpose
The purpose of this Safety and Health
Information Bulletin (SHIB) is to:
- identify potential hazards of an
incorrectly wired elevator controller;
- identify consensus standards applicable
to elevators;
- provide information to employers
regarding the importance of complying
with consensus safety and maintenance
standards for elevators; and
- notify employers of required testing and
verification of proper elevator operation
before releasing elevators into service.
Background
The Occupational Safety and Health
Administration (OSHA) Houston South Area Office
investigated a fatality in Houston, Texas that involved
improper elevator wiring. As a result of improper
wiring of the elevator’s controller, the hoistway door
interlock circuit was bypassed, permitting the elevator car to travel at full-speed with the doors open. This
condition resulted in fatal injuries to an employee
entering the elevator while the elevator was moving.
Accident Description
Mechanics employed by a contracted maintenance company were assigned
to install a new generator for an elevator at a hospital. In addition to
installing the generator, the mechanics also reportedly found and repaired a
short circuit in the system. The mechanics then tested the elevator and returned
it to service. The fatal accident occurred about 25 hours later. There were no
reports of malfunctioning between the time the elevator was returned to service
and the time of the fatal accident.
The victim was trying to board the elevator.
As he approached the elevator, the elevator doors
were closing, and he extended his arms in an attempt
to hold the doors open. The victim then put his leg up
and tried to get into the elevator, which was moving
up. The victim became pinned between the elevator
doors. He was caught between the elevator car and
the hoistway as the elevator continued to move up,
and he died immediately.
The investigation of this accident was comprehensive and systematic. The
investigation concluded that at some point wiring was removed and subsequently
reattached incorrectly to an adjacent electrical terminal of the elevator car
controller (see Figure 1), bypassing the hoistway-door interlocks and resulting
in the elevator’s ability to move with the doors in an open position. A review
of the elevator’s wiring diagram substantiated the improper wiring. |
Figure 1
Controller Panel
Note two wires connected to Terminal
C105 and no wires connected to
Terminal C103. |
Other Information
While there are no specific OSHA standards
addressing the pattern of electrical wiring for elevator
control panels, the Occupational Safety and Health
Act requires employers to provide a workplace that is
“free from recognized hazards that are causing or are
likely to cause death or serious physical harm to his
employees.” To this end, employers need to take
reasonable steps to assure that employees who
perform work on elevators are adequately trained in,
and knowledgeable of, elevator design specifications
and proper maintenance procedures. Further,
equipment must be maintained in accordance with
manufacturer design specifications and operating
procedures.
State governments also regulate the
installation, maintenance, repair, and operation of
elevators. Typically, the state Department of Labor
and Industry or similar state agency oversees elevator
installation and operation. Many of these agencies
require compliance with industry standards and guidance for elevators, as discussed in the following
paragraph. A directory of state elevator code
authorities can be accessed through
http://www.neii.org/. In some cases, local authorities
regulate the installation, repair, maintenance, and
operation of elevators; and employers need to ensure
compliance with these local requirements.
The safe work procedures and equipment
necessary to assure the safety of elevator passengers
and maintenance workers have been developed over
time by the elevator industry. Industry standards and
guidance documents related to this subject are
provided by the American Society of Mechanical
Engineers (ASME), the National Elevator
Manufacturing Industry, Inc. (NEMI, also known as
the National Elevator Industry, Inc. (NEII)), and the
National Elevator Industry Educational Program
(NEIEP).
Specific safety procedures and equipment that are
necessary to prevent incidents similar to the fatality in
Houston are included in the following:
ASME A17.1 - Safety Code for Elevators and
Escalators, 2000
ASME A17.2 – Guide for Inspection of Elevator,
Escalators, and Moving Walks, 2001,
(consolidation of A 17.2.1, A17.2.2, and A
17.2.3)
ASME A17.3 – Safety Code For Existing
Elevators and Escalators, 2002
NEII - Elevator Industry Field Employees
Safety Handbook – 2000
Conclusions
The Houston, Texas accident illustrates the
importance of assuring that elevator components are
properly wired and procedures followed to assure that
the elevator will operate properly before it is returned
to service. Elevator maintenance companies and
employers should take steps to ensure the integrity of
elevator wiring performed during maintenance
activities and adhere to the wiring diagrams specified
by the elevator manufacturer. In addition, employees
performing maintenance and repair work on elevators
must be trained in, and knowledgeable of, applicable
standards, including proper testing and verification
mechanisms required before returning elevators to
service.
Recommendations
To ensure the safe operation of elevators and
the protection of employees, employers need to
assure that employees who install and maintain
elevators are adequately trained and knowledgeable
about proper installation, wiring, and maintenance
procedures. The following guidelines will help reduce
the risk of employee injury from malfunctioning
elevators:
- Integrity of electrical wiring.
Maintenance personnel should review
the controller and advancer wiring.
Wiring diagrams should be kept on
site and reviewed to ensure that the
controller and advancer panel wiring
is correct, to make certain the door
interlocks are operating properly, and
to prevent operation of the elevator
driving mechanism when either the
hoistway door or elevator cab door is
not properly closed.
- Employee training. Maintenance
technicians, elevator inspectors, safety
compliance personnel and consultation
personnel should be familiar with the
consensus safety standards applicable to
elevators. Employers need to ensure that
their personnel are knowledgeable of the
safe procedures to positively control
hazards and the recommended fail-safe
measures to “test and verify” proper
operation of an elevator following
maintenance activities and prior to
releasing an elevator into service.
- Adherence to industry standards. The
referenced industry standards address
proper elevator maintenance and
post-maintenance procedures. Service
personnel need to be knowledgeable of
proper procedures, and employers need
to take reasonable steps to ensure that
their personnel adhere to these
procedures. Employers should implement
effective maintenance control programs
for elevator systems and ensure that
methods are used to detect and correct
any defects affecting safe operation of an
elevator system following maintenance
activities and before the elevator is
returned to service.
References
- American Society of Mechanical Engineers
(ASME). Safety Code for Elevators and
Escalators, 2000. ASME A17.1.
- American Society of Mechanical Engineers
(ASME). Guide for Inspection of Elevator,
Escalators, and Moving Walks, 2001
(consolidation of A 17.2.1, A17.2.2, and A
17.2.3). ASME A17.2.
- American Society of Mechanical Engineers
(ASME). Safety Code for Existing
Elevators and Escalators, 2002. ASME
A17.3
- National Elevator Industry, Inc. (NEII).
Elevator Industry Field Employees Safety
Handbook – 2000.
http://www.neii.org/
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Links/Citations to the websites listed above are offered for the
reader’s convenience. Since OSHA does not control the
information contained in the websites, OSHA cannot assure the
accuracy, relevance, timeliness, or completeness of all of this
information. Moreover, providing links/citations to such
websites does not constitute an endorsement of the websites, or
their content, nor does it suggest that these websites are the
exclusive or most useful sources of relevant information.
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