It’s not uncommon to hear people cheer when the lights and air conditioning automatically come back on when power gets restored after an extended power outage. But there is also a real hazard created if certain equipment, such as saws (e.g.: band saws, table saws, radial saws . . .), sanders (belt and disc), drill presses, and mechanical power presses were to automatically restart after a power failure. This is because someone working or passing through the area might not be aware the equipment has restarted, creating the potential for unintended contact with a turning saw blade, drill bit, or sanding belt, or the unintentional activation of a press cycle. In addition, material that was being worked on when power went out might still be in place when it restarts, possibly causing it to be flung through the air, or jamming at the point of operation on the equipment.
While it may be thought that just the sound being generated by the running equipment would make a person nearby aware that the equipment is running again, this is not always the case; some types of equipment are relatively quiet when running under no load, plus the ambient noise created by other activities and equipment in the area could easily drown out the noise produced by the restarted equipment. So Federal OSHA has a couple of regulations that address this particular hazard, most specifically in their standards for woodworking equipment and for mechanical power presses.
The Federal OSHA woodworking equipment standard for general industry
found at 29 CFR 1910.213(b)(13)
says "On applications where injury to the operator might result if motors were to restart after power failures, provision shall be made to prevent machines from automatically restarting upon restoration of power."
This can be achieved by using woodworking equipment that is manufactured or equipped with a magnetic start switch or similar protective starter switch, sometimes referred to as an anti-restart switch, safety restart switch, or a starter switch with “drop out” protection.
How can you determine if a specific piece of equipment is provided with a functioning safety start switch? When I conduct mock-OSHA inspections, I simply unplug a piece of equipment while it is running (under no load), or I turn off power to the equipment at its main electrical cut-off switch or breaker, and then let it come to a complete stop. Then I restore power to the equipment by plugging it back in, or by turning it back on at the main cutoff switch or breaker (I always use a second person to assist me by having them watch to make certain no one inadvertently gets too close to the machine during testing). If the piece of equipment automatically restarts when I restore the power, then it does not
have the required anti-start switch (or the anti-start switch is not functioning properly - they do wear out or malfunction sometimes). But if the equipment does not
restart when I restore power at the plug, main cutoff switch, or breaker, and will only run after activating the equipment’s primary start button or switch, then it does
have the required anti-restart protection.
The OSHA standard applicable to mechanical power presses, which requires the same basic type of protection, is found at 29 CFR 1910.217(b)(8)(iii)
. In addition, paragraph 29 CFR 1926.304(f)
of the OSHA construction
standards for woodworking tools mandates that “All woodworking tools and machinery shall meet other applicable requirements of American National Standards Institute, 01.1-1961, Safety Code for Woodworking Machinery”
; and that ANSI standard also requires anti-restart switches for the same types of equipment.
But what about equipment not used for woodworking? For example, a band saw being used for cutting steel rods instead of wood? Or a drill press used to drill holes in pieces of angle iron as opposed to a piece of wood? Although the hazard is basically the same, the OSHA standards do not specifically require anti-start switches for equipment used to cut metal and other materials. However, OSHA did publish a letter of interpretation
regarding this subject. In that letter, OSHA explains that the agency would refer to any applicable listing requirements for the equipment issued by Nationally Recognized Laboratories (such as Underwriters Laboratories), and where warranted enforce the use of anti-restart switches via 1910.303(b)(2)
(listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling
). OSHA could also refer to applicable ANSI standards for specific types of equipment and, if they require a safety switch, the agency might cite the employer under the General Duty clause of The OSH Act of 1970 (employers must protect workers from recognized hazards
). OSHA could also issue a citation under the General Duty Clause if it was determined that a safety switch originally installed by an equipment manufacturer was later removed or bypassed by the employer, or was not maintained in a functioning state.
So what options do employers have if they determine their equipment does not have a properly functioning anti-start up switch? Equipment manufacturers and their vendors may have replacement safety startup switches that could be installed by a qualified electrician. There are also after-market devices available in different configurations that can be plugged into, or wired in lieu of, power cords for equipment (again, by a qualified electrician), such as those marketed by JDS Products (www.jdsproducts.com
) and other companies.
Amputations are a prevalent problem for operators of woodworking equipment, and not being aware that a piece of equipment has automatically restarted after a power interruption a contributing cause. Therefore, I will close by urging you to take an inventory of woodworking (and similar) equipment to determine if each piece is equipped with a properly-functioning anti-start switch, and installing one / repairing any that do not. And please add safety starter switches to your site or equipment safety inspection checklists if not already on there. Your actions could possibly save an employee, and you, from suffering a lot of grief, pain and misery.