Your company’s T&D switching and clearance procedure must first establish the authority, responsibility and procedure for operating disconnecting devices; and requesting, issuing and releasing clearances affecting the company’s T&D electrical system.
First, your procedure must cover who will be authorized to operate the company’s T&D system. Larger electric utilities have system operators on duty 24 hours a day who are authorized to operate the T&D system. No other person or group of employees, other than the system operator, is authorized to operate the T&D system. Smaller utilities may not have a system operator. Instead, they have designated employees – including foremen, lead workers and supervisors – who are authorized to oversee the company’s T&D switching and clearance procedure.
Next, the written switching and clearance procedure must detail what part of the T&D system is under control of the system operator, if one exists. Typically, the system operator has control of the T&D system from 600 volts to the transfer point at the utility’s generation system (refer to OSHA 1910.269(d) for generation switching and clearances) or intertie point with adjacent utilities, with the exception of distribution transformer cutouts and padmount transformer bayonet fuses. This means any switching or issuing clearances on the T&D system under the exclusive control of the system operator must be authorized and directed by the system operator. If a system operator is not in control, the T&D written switching and clearance procedure must detail the authority of the company’s designated employees.
But does OSHA 1910.269(m) stop at 600 volts? If your answer is yes, you need to review the OSHA 1910.269 preamble. It states:
“OSHA firmly believes that certain procedures must be followed for de-energizing live parts at any voltage over 50 volts if employees will be in contact with the parts during the course of work. Contact with electric circuit parts energized at 600 volts or less can be as fatal as contact with higher voltages. … These are the steps that were proposed in 1910.269(m) and that have been carried into the final rule. These are the same steps that are set forth, without a voltage limitation, in 1987 NESC Section 423, on which the proposal was based.”
Yes, OSHA 1910.269(m) requires you to de-energize and issue a clearance on all T&D systems down to 50 volts, or you must consider the lines and equipment as energized. When was the last time you saw an underground 120/240-volt secondary service that had been disconnected from the padmount transformer and meter base tagged with clearance tags on both ends? OSHA 1910.269(m) requires a clearance and tags, or the worker must work the cable as energized. Has OSHA ever cited a utility for not locking or taking a clearance below 600 volts? Yes, they have.
If your written switching and clearance procedure specifies the system operator’s control is between 600 volts and the transfer point at the utility’s generation system or intertie point with adjacent utilities – with the exception of transformer cutouts and fuses – then your written switching and clearance procedure must also detail how the electrical system below 600 volts is to be switched and tagged, or worked as energized.
No System Operator?
If your utility does not have a system operator, your written switching and clearance procedure must specify who will be authorized to operate switches and issue clearances. Foremen, lead workers and supervisors are typically trained and authorized to operate or oversee the operation of the company’s switches and disconnecting devices. They must also be trained and authorized to hang tags and issue clearances on sections of the T&D system.
A few important details I find lacking in many companies without a system operator – and yes, I do find the same problem at some utilities that have system operators – are the process of switching, not hanging tags and not issuing clearances on some parts of the T&D system. Even though these parts are, or should be, under the company’s switching and clearance procedure requirements, authorizations to switch and issuing clearances do not occur. Consider the following example.
A tree falls into a single-phase, 7.2 kV overhead line at 2 a.m., breaking the phase conductor and neutral. The line is off a country road and runs one mile from the tap-off point to a dead end. A crew is called to go out and take the tree off the line, splice the phase and neutral conductor together, then re-fuse the cutout. The crew goes out to the line cutout, finds it open and drives the single-phase tap to the downed tree and conductors. The crew knows the area well and knows there is no other source beyond the open line cutout. The crew assembles and has a tailboard meeting to discuss how they are going to put back up the phase and neutral. They agree grounds must be installed on both sides of the break before contacting the downed conductors. The crew then splices the conductors together and runs back to the line cutout to re-fuse and energize the tap. They then head home to their warm beds.
A Plan Gone Wrong
What is wrong with their plan? The foreman, lead worker or supervisor did not fill out a clearance tag, and they did not hang the tag at the line’s open cutout. They did not issue themselves a clearance, nor did they inform their crew during the tailboard that they had hung a tag for themselves and had issued a clearance from the open cutout to the end of the line.
Yes, but they are the only crew out on this cold, windy night and the nearest crew is probably 100 miles away. It does not matter where the next crew is. The person in charge must, per OSHA 1910.269(m), ensure the switch is open; tag the switch with a proper, fully completed clearance tag; issue a clearance from the open switch to the end of the line; and notify the crew of the clearance parameters. Additionally, the crew’s company switching and clearance procedure must require a clearance be issued and a tag hung on every switch before the line or equipment can be grounded and worked as such.
The OSHA 1910.269 preamble states:
“Paragraph (m)(2)(ii) defines the general application of the rule to crews working on lines that are not under the control of a system operator. In the usual case, one employee is designated to be in charge of the clearance. All the requirements in paragraph (m)(3) apply, with the employee in charge of the clearance taking the place of the system operator. In this manner, the final rule provides protection against the unintended energizing of transmission and distribution lines without requiring all lines to be under the control of one employee. One employee in a crew will be in charge of the clearance for the crew; procedures will be followed to ensure that the lines are truly de-energized; tags will be placed on the lines; and procedures will be followed to remove the tags and re-energize the lines.”
If clearance tags are not hung at all clearance points and a clearance is not issued, the person in charge has not taken control of the line or equipment, and he and the crew cannot work the line as de-energized and grounded. Any other authorized employee who is a person in charge for the utility can re-fuse and close the line cutout. Can it happen? Yes. Does it happen? Yes.
If a proper clearance is not developed and issued, OSHA 1910.269(m) does not allow workers to install grounds and work the lines and equipment as if they were de-energized and grounded.
In fact, if you read the first part of the OSHA 1910.269 preamble discussing paragraph (m), OSHA seriously considered not allowing electric utilities to use a tagging system but instead considered requiring the use of a locking system. This would have required each qualified electrical worker to install their own personal lock on every switching device before beginning work. The OSHA 1910.269 preamble states:
“The treatment of lockout vs. tagout presents OSHA with a difficult regulatory dilemma. On the one hand, if the issue were simply whether a lock or a tag will be better able to prevent equipment from being reactivated, there is no question that a lock would be the preferred method. … In the Final Rule, OSHA has determined that lockout is a surer means of assuring de-energization of equipment than tagout, and that it should be the preferred method used by employees. However, the Agency also recognizes that tagout will nonetheless need to be used instead of lockout where the energy control device cannot accept a locking device. Where an energy control device has been designed to be lockable, the standard requires that lockout be used unless tagout can be shown to provide ‘full employee protection,’ that is, protection equivalent to lockout.”
Difficult to Prove
To say a tagging clearance procedure is equal to a locking clearance procedure is very difficult to prove, which means the utility’s switching and clearance procedure, using tagging, must be squeaky clean and implemented identically each and every time. The OSHA 1910.269 preamble states:
“However, it is the fourth element of a clearance procedure, discipline, which is the most difficult to incorporate into a regulatory approach in the Final Rule. Not surprisingly, it also reflects the most serious limitation of tagout which does not arise with lockout.”
Time to Review
Review your switching and clearance procedure yearly and make any necessary changes. If changes are made, retrain the affected workers. Also, ensure your switching and clearance procedures are always identically applied in every situation, no matter when and where and by whom, from 50 volts up. Otherwise you must work the lines and equipment as energized.
There are very specific requirements for the clearance tag. It must:
• Be of a unique color
• Be used only when issuing clearances and nothing else
• State “Employees are at Work”
• Be able to hold up to environmental conditions
Clearance tags must be hung and proper clearances issued by your system operator or designated employee before de-energized and grounded work can begin. Doing anything less will potentially get your company cited or, worse, someone may be injured or killed.
About the Author: Brian Erga, president of ESCI Inc., has more than 36 years of electric utility expertise and holds a BSEE degree. An expert on safety practices and work methods related to the electric utility industry, he is a member of IEEE/ESMO, NSC, NFPA, ASTM F18 and a member of NESC Subcommittee 8, responsible for NESC Part 4 “Rules for the Operation of Electric Lines.”