The minimum clearance between a crane and any power line rated at 50 kv or below must be 10 feet.

Before assembly or disassembly of a crane, the employer must determine if it could come within 20 feet of a power line (up to 350 kV). If so, the employer must take one of the following actions:

(a) Confirm with the power company that the line is de-energized and visibly grounded at the worksite. (b) Make sure no part gets within 20 feet of the power line.

(c) Follow Table A, which has minimum clearance distances based on voltage.

TABLE A: Minimum Clearance Distances Based on Voltage

Cranes cannot be assembled/disassembled below an energized power line or within the Table A clearances from a power line. If Table A is used, the owner/utility must provide the power line voltage to the employer within two days of a request.

Power lines must be assumed to be energized until they are confirmed to be de-energized and visibly grounded. Warnings about electrocution hazards must be posted conspicuously in the crane cab and outside the cab in view of the operator (except for overhead gantry and tower cranes).

The work zones must be demarcated 360 degrees around the equipment to prevent encroachments within 20 feet of a power line. If the line is not de-energized, a meeting must also be held with the crew before operations begin to review the location of the lines and procedures to prevent encroachment. Measures similar to those required during assembly/disassembly must be taken to prevent encroachment, but in this case an insulating link between the load line and the load is also an option.

Operators and crew members must be trained:

• On the procedures to follow in the event of power line contact
• To presume that power lines are energized until confirmed and visibly grounded
• To presume that power lines are not insulated until otherwise confirmed by the owner or a qualified person
• On the limits of insulating links and other devices (e.g. proximity alarms)
• On proper grounding procedures and their limitations.

Spotters must also get applicable training.

What if the line is not de-energized?

If the line is not de-energized, the employer must take the following actions:

• Conduct a meeting with the assembly/disassembly crew to review measures to prevent encroachment.
• Use only nonconductive tag lines.
• Use a dedicated spotter, a proximity alarm, a range control warning device, an automatic limit device or an elevated warning line/barrier placed in view of the crane operator.

Exceptions to Table A? Follow these Minimum Precautions

If work must operate closer than the Table A values, then the following precautions must be taken at a minimum:

• The employer must show that Table A is infeasible and that it is infeasible to de-energize and ground or relocate the line.
• Safe distances must be determined by the owner/operator of the line or a registered professional engineer who is a qualified person.
• A planning meeting must be held and procedures developed must be implemented (if procedures are inadequate, work must be stopped and new procedures established or the line must be de-energized).
• Automatic re-energizing devices must be inoperative.
• A dedicated spotter must be assigned.
• An elevated warning line/barricade or an insulating link must be installed between the line and the load, except for work on electrical transmission/distribution lines covered by Subpart V (additional provisions take effect one to three years after the effective date).
• Non-conductive rigging must be used.
• A range-of-motion limiting device must be used.
• Non-conductive tag lines must be used.
• Barricades at least 10 feet from the equipment (where feasible) must be established.
• Equipment must be properly grounded.
• Workers must be kept from touching the line above the insulating link.
• Only essential personnel are allowed in the area.
• Insulating line hose or cover up must be installed by the owner/operator unless unavailable.
• The owner and user must meet with the equipment operator and other workers to review procedures.
• One person must be identified who will implement the plan and can stop work if necessary.
• Documentation of these procedures must be immediately available on site.
• Safety devices and aids must comply with manufacturers’ specifications.
• All employees must be trained in power line safety per 1926.1408 (g).

Equipment Clearance Distances

Equipment traveling under or near a power line must:

(a) Have a lowered boom/mast and support system
(b) Obey minimum clearance distances set in Table T (c) Reduce speeds to minimize breaching (d) Use a dedicated spotter if closer than 20 feet (e) Illuminate or identify the power lines at night

(f) Identify and use a safe path of travel.

TABLE T

Minimum clearance distances while traveling with no load

Dear Mr. Blood:

This is in response to your October 13 letter requesting an interpretation of an Occupational Safety and Health Administration (OSHA) standard addressing the operation of a crane in close proximity to overhead power lines. I apologize for the delay in responding to your inquiry.

With regard to what is acceptable as insulating barriers to prevent physical contact of equipment or machinery with electric distribution and transmission lines when the equipment or machinery is operating within 10 feet of the power lines, please be advised as follows: Rubber insulating equipment meeting the requirements of 29 CFR 1910.137 is normally intended as protection from "brushing" type contact for employees working on the lines. Although 1910.137 is not applicable to construction work, it may be used as a compliance guide for barriers required under the exception to 1926.550(a)(15), under certain conditions. If hard direct contact with the line is not likely, rubber insulating equipment can provide protection from brush contact with the power line. However, if direct impact with the lines is reasonably likely or expected, this equipment will not provide the necessary protection. In such cases, other types of barriers would be required, such as those listed in the National Safety Council Data Sheet No. 1-743New90 and the types of plastic guard equipment covered in ASTM F968, Specification for Electrically Insulating Plastic Guard Equipment for Protection of Workers. Although guards of a type consisting of ABS plastic, 1/8-inch thick, (approximate puncture strength 50,000 volts) are often successfully used on 15KV and 34.5KV systems, none are totally impact proof to the extent that strong direct blows would leave the air gap integrity unchanged or not cause sliding or other adverse movement along the line.

While the "goal post" type of guarding approach to overhead line safety probably provides the most durable means of withstanding barrier impact, it should be remembered that no practical barrier can absolutely prevent contact of a crane (or similar material handling device), simply because the capabilities of such heavy operating devices normally overwhelm any obstruction that may be installed.

If we can be of any further assistance please contact me or Dale Cavanaugh of my staff at (202) 219-8124.

Sincerely, Roy F. Gurnham, P.E., J.D. Director Office of Construction and Maritime Compliance Assistance

October 13, 1993

Francis Perkins Technical Data Center Department of Labor Building Room N 2439 200 Constitution Avenue N.W.

Washington, DC 20210

Dear Sir:

We're requesting a definitive interpretation of the following standard:

1926.550(a)(15)

Except where electrical distribution and transmission lines have been deenergized and visibly grounded at point of work or where insulating barriers, not a part for an attachment to the equipment or machinery, have been erected to prevent physical contact with the lines, equipment or machines shall be operated proximate to power lines only in accordance with the following:

(i) For lines rated 50 kV. or below minimum clearance between the lines and any part of the crane or load shall be 10 feet;

(ii) For lines rated over 50 kV., minimum clearance between the lines and any part of the crane or load shall be 10 feet plus 0.4 inch for each 1 kV. over 50 kV., or twice the length of the line insulator, but never less than 10 feet;

Questions:

What would qualify as an insulating barrier if we have a contractor, who needs to drive sheet piling adjacent to 12000V and 440V lines, where the lines are unable to be deenergized? The electric utility installed insulating barriers i.e., boot/cover, to cover the lines? Would this type of cover be acceptable when addressing the standard?

The contractor is under the assumption that when the lines are booted/covered, that he can work next to the lines and disregard the 10 foot minimal standard. We have contacted numerous OSHA compliance officers and area officers and received different interpretations. These interpretations have ranged from working a minimum of 10 feet from the energized lines to being able to work next to the energized lines.

We await your clarification on this particular issue.

Sincerely, St. Paul Fire and Marine Insurance Company Ivan Blood Account Specialist/Construction Loss Control Services Richard L. Hegerle Account Specialist

Loss Control Services