Recap
We wrapped up Part 2 with a common HVACR task to demonstrate how LOTO, according to OSHA 1910.147 Subpart J, may be sufficient for controlling hazardous non-electrical energy, such as rotating or moving parts, but would not be when the task transitions to the electrical components. This becomes especially problematic and far too common when direct exposure to electricity sneaks into the work scope unnoticed.
To recap, when workers face indirect hazards from electricity, meaning after it’s been changed to another form by motors, heaters, compressors, etc., the hazards take the form of kinetic or potential energy, such as hydraulic pressure, pneumatic force, high temperatures, compressed springs, and moving machinery. In such cases, a standard LOTO program under 1910.147 Subpart J would be adequate to protect the workers and comply with the regulations.
But this dynamic significantly changes whenever the workers’ activities expose them directly to electrical energy, such as servicing the motors, heating elements, transformers, VFD’s, contactors, and other electrical components.
When 1910.147 is Not Enough for LOTO
A LOTO program using only 1910.147 Subpart J is inadequate for the following reasons:
- First and foremost, 1910.147 Subpart J was never designed nor intended to address electrical hazards of shock or arc flash. This limitation is clearly stated up front in its scoping application according to 1910.147(a)(1)(ii)(D) as discussed in Part 1 but is often overlooked by many safety professionals and others who are responsible for developing their company’s COHE program. They can’t be fully blamed for this oversight because the OSHA regulations covering COHE are fragmented within several different 29 CFR standards which can make it very difficult to pinpoint the specific but different COHE mandates.
- The second reason for the inadequacy of 1910.147 Subpart J is due to the special nature of electricity and the unique abatement methods needed to prevent shock and arc flash accidents, which will be explained later.
- Lastly, when the worker is using LOTO to control electricity, they must also be a qualified electrical person under the electrical safety program while holding status as an authorized worker under the LOTO program.
A mechanic may not carry out work of the electrical equipment, such as the motors or solenoids of motor or solenoid operated valves (MOV/SOV) but is permitted to manipulate circuit breakers and safety disconnects to establish the isolation points needed for their LOTO.
The act of opening and/or closing energized electrical isolation points, regardless of the reason, contains some level of electrical risk. This does not mean such non-electrical workers must be a fully qualified electrical person, but they need some level of electrical safety training incumbent on the hazards they face when carrying out their assigned duties so they’ll be able to identify the hazard, assess the risk of likelihood and severity, and then take the necessary mitigation actions.
This is clearly mandated by 1910.332(b)(2), “Employees who are not qualified persons shall also be trained in and familiar with any electrically related safety practices which are necessary for their safety.”
This is concurrently validated by NFPA® 70E® section 110.4(A)(2).
Why We Must Move to OSHA 1910.333 Subpart S to Control Electrical Energy
To properly control electrical energy, we must transition away from 1910.147 Subpart J to the correct standard – OSHA’s electrical standard 1910.333 Subpart S titled “Selection and use of (electrical) work practices”.
This workplace safety regulation was designed to minimize “electric shock or other injuries resulting from either direct or indirect electrical contact when working on or near equipment that are or may be energized.”
The “indirect electrical contact” statement used here implies injuries from arc over or flashover incidents common with medium to high voltage circuits where the proximity of the worker to exposed energized parts can cause current to pass through the air. At lower voltages, < 3kV, a person must physically touch an energized part to receive a shock. However, with higher voltage circuits, contact is not necessary for a shock to occur, as electricity can literally “reach out and touch you,” as we see with lightning.
Air is a good insulator, but its dielectric strength to prevent the passage of current is directly proportional to the applied voltage. Like all insulators, air’s dielectric property, called the Minimum Air Insulating Distances (MAID), has limitations based primarily on the air spacing between conductive parts, including the human body, energized at different electric potentials. The greater the voltage, the greater spacing of air is needed to prevent a flashover.
Most of the shock protection boundaries also contain an “inadvertent movement factor,” which is extra spacing added to compensate for unexpected movement by the worker to minimize the possibility of unintentional contact.
Other contributors such as elevation, humidity or lack of humidity, etc. can also affect air’s dielectric properties, but this topic is outside of the scope of this article. To gain a better understanding of the attributes of air and distance as they relate to protection against electric shock through the Restricted Approach Boundary (RAB) and Minimum Approach Boundary (MAD), please see my article titled “Avoid Contact – The Shock Boundary Without a Distance.”
I provided this clarification to reduce any confusion that the “indirect electrical contact” mentioned in this OSHA standard is for shock prevention and not related to my previous statement “indirect exposure to electricity,” which was used in context with LOTO to describe hazardous energy after it has been converted from electrical energy to kinetic, mechanical, thermal or other forms of hazardous energy.
Locating Electrical LOTO Requirements in the OSHA Regulations is Not Intuitive
Unfortunately, in true government fashion, finding the electrical LOTO requirements within this OSHA safety standard (1910.300 Subpart S) is neither intuitive nor easy. This misplacement explains the oversight by EHS professionals responsible for their company’s COHO programs.
Additionally, within Subpart S, there is no mention of electrical “lockout/tagout” until you reach subsection 1910.333(b)(2), which is preceded by the main section titled “Working on or near exposed deenergized parts” rather than lockout/tagout. Sometimes navigating the OSHA regulations is like finding the proverbial needle in the bureaucratic haystack.
I once asked the author of OSHA’s electrical standards why are there so many separate LOTO provisions located in so many different OSHA regulations for General Industry alone, consisting of 1910.147 Subpart J, 1910.269 Subpart R and 1910.333 Subpart S, rather than formulating one LOTO standard containing individual sections to control different types of hazardous energy. He explained at the time when Subpart S and Subpart R were being developed for electrical hazards, OSHA was not confident Subpart J was adequate for electricity, so rather than revising Subpart J to include electricity, they wrote two new standards for electrical LOTO.
But he admitted that, in hindsight, combining everything related to controlling hazardous energy through LOTO into one standard, then separating them as needed, was probably the best approach. I must admit I chuckled a little when I heard his reasoning which reinforced my belief the word “government” and “efficient” are often not very compatible.
According to OSHA, “Exposed Deenergized Parts” Has Many Different Conditions
To fully understand this concept of “exposed deenergized parts,” we need to review 1910.333(a)(1) in detail, which states in part, “Live parts (energized at 50 volts or more) to which an employee may be exposed to shall be deenergized before the employee works on or near them…” From there, the logical conclusion is to find the meaning of the words “Exposed” and “Deenergized” as defined by 1910.399.
“Exposed” (as applied to live parts.) is defined as “Capable of being inadvertently touched or approached nearer than a safe distance by a person. It is applied to parts not suitably guarded, isolated, or insulated.”
“Deenergized” is defined as “Free from any electrical connection to a source of potential difference and from electrical charge; not having a potential different from that of the earth.” The word “potential difference” is essentially a description of voltage.
Reading subsection 1910.333(a)(1), then using the definitions by themselves to understand them, has unfortunately led people to erroneously conclude OSHA only requires electric parts at 50 volts or more to be ‘deenergized,’ meaning having no voltage or being connected to a source of voltage before they’re allowed to work on it.
All it takes to deenergize a motor is to open the circuit breaker or its disconnect. But would this single step by itself allow us to disconnect the motor leads with our bare hands? Of course not! Without locks and tags affixed to the correct circuit breakers or switches, nothing prevents another worker or the control circuit from inadvertently reenergizing the circuit. Some will argue, “But the standard says all we only need is to ‘deenergize’ the motor.” That is only partially correct and is completely unsafe.
A caution must be shared here. Please note: the 1910.333(a)(1) governance does not specify what type of current, ac or dc, the 50-volt threshold starts. Regardless, if it’s an ac or dc system we’re working on, it’s mandated at 50 volts or more.
There have been situations where consensus standards have taken liberty to increase the shock threshold to 100 Vdc. Such provisions are contrary to OSHA laws and regulations, which take supremacy over consensus standards. We will discuss this issue later in Part 5.
Understanding the Context is Needed Rather than Only Definitions
The reason comprehending the full context of “deenergizing the equipment” with the standard must be understood is because the details are concealed within the LOTO provisions of OSHA’s electrical safety standard in 1910.333. It throws several subtle curve balls to achieve a “deenergized” state outside of its definition.
To further complicate the situation, we must also be aware the word “deenergized” is used several times in the standard but with differing conditions, including but not limited to LOTO. As painful as it may seem, correctly interpretating OSHA laws in this case must be accomplished through a full contextual understanding of the entire regulatory directives by careful study.
That said, let’s delve into the details to make sense of it all.
Definition of Deenergized Says...
OSHA 1910.333(b)(1) states in part “electric circuits and parts that have been deenergized but not locked or tagged out shall be treated as energized parts.”
Did you catch that? Even after it’s been “deenergized” (as defined), it must still be treated as energized unless a LOTO is used. So, the second condition for electrical equipment to be “deenergized” requires LOTO.
...and Other Requirements to be Deenergized
However, it doesn’t end there. The circuit or part is still not considered safe to work on or is “deenergized” unless the following additional steps are in place and completed:
- The employer must have written procedures to “deenergize” the equipment.
- The circuit or equipment must be disconnected from all sources of electricity (this is essentially the definition of deenergized) without reliance on control circuits as the sole disconnecting means.
- Stored electrical energy must be discharged and capacitors shorted and grounded.
- Stored non-electrical energy must be blocked or relieved.
- A qualified person must attempt to operate the equipment to verify it is “deenergized.”
- A qualified person must use test equipment to verify the part(s) are “deenergized” (meaning nominal voltage is absent) to include any energy from induction or back feeds.
- If the system nominal voltage is over 600 volts, the test equipment must be checked for proper operation before and after testing the part(s). Interestingly, this critical verification is not an OSHA requirement for equipment energized at ≤ 600 volts, which will include common industrial voltages of 480, 277, 240, 208 and 120 volts.
Only after the previous steps have been performed successfully can the electric circuits, equipment, or parts be officially deemed “deenergized” and “safe” to work on and compliant with OSHA regulations. Anything less than this is unsafe, significantly increases risk of shock or arc flash, and subjects the employer to fines and civil actions.
For more information on the topic of deenergized as used by OSHA, please see my article titled “De-energized – More Than Flipping the Switch To Off”.
A Comprehensive LOTO Program is Needed
An employer’s control of hazardous energy program (COHE) must be comprehensive by including provisions from both 1910.147 Subpart J for non-electrical energy and 1910.333 Subpart S to address electricity. This must be followed with regular LOTO training of all workers, not only for the “Affected Employees” (those who operate equipment) and “Authorized Employees” (those who repair the equipment) but must also include “All Other Employees” as discussed in Part 2.
As a reminder, Subpart S has additional electrical safety training requirements to be a “Qualified (electrical) Person” according to 1910.332 – Training for both those who are fully qualified or have limited task qualifications.
Let’s not forget that adherence with OSHA regulations only establishes the bare minimum obligation a company must follow to avoid violating the law and paying fines and penalties. A “compliance alone is adequate” mindset can lure employers into a false sense of security that the employees are sufficiently protected from harm.
If you’re reading this article, then you’re likely a person who comprehends the myopic shortfalls of a compliance-only approach to safety and are seeking improvement opportunities to better worker safety.
LOTO Under the Construction Standard 29CFR1926 is Not Lockout
Before concluding this Part, I believe we should briefly discuss LOTO for those who perform electrical work during construction because this work practice officially falls under the scope of OSHA’s Construction standard 1926.
Controlling hazardous energy for the construction industry is found in two OSHA regulations. The first is in 1926 Subpart K – Electrical, which covers new electrical installations not related to electric utilities often referred to as “Utilization Equipment.” Secondly, it appears in 1926 Subpart V – Electric Power Transmission & Distribution, which applies during the initial construction of powerlines and similar electric utility infrastructure.
Unlike OSHA’s General Industry standard 1910.269 Subpart R for electric utilities, 1926 Subpart V does not have instructions for electric power plants while being built. Controlling hazardous energy for transmission and distribution power lines and substations under 1926 Subpart V during construction is through clearance orders and are identical to those required after they’re placed into service pursuant to 1910.269 Subpart R.
However, for those who primarily build non-utility electrical infrastructure for utilization purposes, such as industrial plants, commercial buildings, refineries and now data centers within the construction industry, then the control of hazardous electricity is driven by 1926.417 Subpart K.
But here’s the catch: while 1926.417 is titled “Lockout and Tagging of Circuits,” which logically leads one to assume it would include “locks” and “tags,” this standard only speaks of “tagging” within its three short sentences. The words “locks,” “applying locks,” or “lockout” are never mentioned.
One reason for the significant difference between 1910 Subpart S compared to 1926 Subpart K, is the construction standard was never revised before OSHA’s technical writer of electrical standards retired from the federal government.
Because of this problem, it is strongly recommended those performing electrical construction work should, at a minimum, adopt electrical safety practices, including LOTO, as mandated by the general industry standard 1910 Subpart S. The employer should also augment this with NFPA 70E to ensure workers are sufficiently protected. Failure to do so could result in a violation of the General Duty Clause.
Lastly, the content of the vast majority of in-person and online LOTO training classes and certificate courses, such as OSHA’s 7115, only cover 1910.147 Subpart J while identifying electrical disconnecting devices and load equipment without referencing the necessary actions to address direct electrical exposure under 1910.333 Subpart S or NFPA 70E.
e-Hazard's LOTO Class
Seeing this significant gap that can endanger workers’ lives, we at e-Hazard have developed a Control of Hazardous Energy (LOTO) training class using a comprehensive curriculum that encompasses all the pertinent regulations, standards, and practices to ensure workers are fully protected.
Conclusion
Starting in Part 4, I’ll share some practical methods to reduce hidden risks while simultaneously increasing safety margin for employees, especially for electrical LOTO practices. I’ll incorporate those from NFPA 70E, Standard for Electrical Safety in the Workplace, which doesn’t limit itself to either maintenance activities or construction activities; the standard applies to both industries.
