Standard Interpretations - Table of Contents|
| Standard Number:||1926.400|
January 8, 1986
Mr. Albert Davis, Business Manager
Dear Mr. Davis:
Thank you for your recent inquiry requesting our interpretations of specific construction safety and health standards pertaining to the electrical trades.
After researching your questions in depth, the following interpretations are offered to help you in your efforts to provide a safe and healthful workplace:
Question 1. 1926.400(a) - Is this section saying that when there are specific requirements provided by the Construction Standards 1926, they take precedence over requirements provided by the NEC, NFPA and ANSI?
1926.400(a) specifically references the NEC, NFPA 70-1971 and ANSI C1-1971 unless otherwise provided by regulations of this part (Subpart K of the 1926 Standards). In brief what this is saying is that the provisions and requirements of the references shall be followed except where Subpart K specifically negates a provision/requirement of the codes (NEC/NFPA).
Question 2. As applied to 1926.401(i) what is the interpretation of:
a. Open Wiring
c. Unauthorized Personnel
a. Open Wiring - True open wiring was an older method of installing interior wiring in which the wires were run exposed on the ceiling, roof structure, or walls. They were supported on porcelain insulators of either the knob or the cleat type. Frequently the conductors were bare. Open wiring as now used refers to the individual conductors being physically separated as in the McGill "String-O-Lights", and being run exterior to the walls, ceilings, structure.
b. Inaccessible - Applied to wiring methods, inaccessible means not capable of being removed or exposed without damaging the building structure or finish of the building. As applied to equipment, electrical vaults, etc., inaccessible means guarded by barriers, locked doors or gates, or other equivalent means.
c. Unauthorized Personnel - Personnel who are not familiar with the construction, operation and hazards of operation relative to equipment, electrical systems, or other activities which they are not expected or authorized to perform, operate or construct.
Question 3. 1926.401(j)(2) - In a multi-story building or other building where a number of different crafts, pipefitters, sheet metal workers, fireproofers, etc., must work within arm's length of temporary lighting, please advise if the following is permitted:
a. Open Wiring such as McGill "String-O-Lights". b. Lighting Strings using "Romex" type conductors.
What is your interpretation of cord? Is "Romex" type cable considered to be a cord?
"It seems to me that 1926.401(j)(2) requires the use of heavy duty electric cords for temporary lighting where "unauthorized" workers must work within arm's length of lighting strings--is this a correct interpretation? If it is a correct interpretation, then why is it not being enforced by OSHA compliance personnel?"
Starting with your request for definitions:
(1) Cord - A cord is a small cable, very flexible and insulated to withstand a certain amount of wear. There is no sharp dividing line in respect to size between a cord and a cable and, likewise, no sharp dividing line in respect to the character of insulation between a cord and a stranded wire. In general, a cord usually consists of stranded conductors.
(2) Stranded Wire - A group of small wires used as a single wire. A wire has been defined as a slender rod or filament of drawn metal. If such a filament is subdivided into several smaller filaments or strands and is used as a single wire, it is called a stranded wire. Again, there is no sharp dividing line of size between a stranded wire, a cord, or a cable. If used as a wire, for example in winding inductance coils or magnets, it is referred to as a stranded wire, and not a cable. If it is insulated, it is called a cord.
(3) Cable (a) A stranded conductor (single-conductor cable) or (b) a combination of conductors insulated from one another (multiconductor cable). The component conductors of the multi-conductor cable may be either solid or stranded, and may or may not have a common insulation covering. Some manufacturers refer to a cable as a solid wire heavily insulated, and in general, this is a suitable definition. However, in reality the term cable is a general term.
It is not clear where you obtained the measurement of "arms length". The standards you have identified do not use this phrase or indicate a precise measurement. What the standards are trying to prevent is injury or death from electrocution. This could come about from damaged insulation on the temporary light cords/cables and direct contact from employees touching the exposed conductors or indirect where the conductors touch metal framing studs, pipe, ducts, etc., and employees touch the energized metal.
OSHA does not recognize "arm's length" of such hazards as protection of the employees.
Generally speaking, tools, equipment, and machinery used on construction sites suffer the effects of hard usage as well as weather. This is true in the case of temporary lighting. For that reason the standard 1926.401(j)(2) requires the use of heavy duty cords. In terms of the National Electric Code, this translates to types S, SO, ST, and STO, or equivalent insulation. As with any piece of equipment, the different types of temporary lighting available may be misused.
In general, industrial use of McGill "String-O-Lights" may be permitted provided:
1. No work performed in the area is exposing the lights or electrical conductors to hard usage or damage.
2. The lights are strung and hung in a manner recommended by the manufacturer, and in accordance to the applicable codes.
3. The insulation is intact and has no bare spots. As an example, the lights could be used to light a hallway for personnel putting down tile, providing they were out of reach of either tools or equipment.
It should be remembered that some of the temporary lighting used does not have the insulation of the S, SO, ST, STO, or equivalent types. Too often our compliance officers have inspected sites and found the lights suspended by wrapping them around piping, metal beams, etc. Frequently the insulation has been found to be damaged from being dragged over objects, pulling on it, or by hanging other objects from the conductors, or by employees with equipment working around the lights. In these situations, a hazard may be presented and cited accordingly.
In regards to the use of "Romex" cable. Romex is a trade name. The electrical classification is non-metallic sheath cable. If used in accordance with the applicable codes and its construction is water and flame resistant it may be used for temporary lighting. Connections for temporary lights must meet the National Electrical Code requirements for wire nuts, strain relief devices, and insulation. Pin type connections in stranded or solid conductors are not allowed and may be cited.
You mentioned in your letter that you referred the above questions to four different compliance officers and received four different answers. If you could be more specific about that, it might assist us in clarifying the above matters among our field staff.
I hope the information contained in this letter answers your questions sufficiently. Feel free to contact this office if we can be of further assistance.
References: National Electrical Code-1971 American Electricians' Handbook, Tenth Edition-1981
Standard Interpretations - Table of Contents|