Archive Notice - OSHA Archive

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OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at

June 17, 2002



MEMORANDUM TO: Michael G. Connors,
Regional Administrator, Region V
FROM: Russell B. Swanson, Director
Directorate of Constructionm

Richard Fairfax
[Directorate of Enforcement Programs]
SUBJECT: Flexible Corrugated Plastic Covers for Temporary Use to Cover Live Electric Parts in Switch and Panel Boxes

This is in response to your May 21, 2001, memo addressed to the [Directorate of Enforcement Programs (DEP)], in which you ask for clarification on the use of a temporary electrical panel box cover manufactured by SP Products Inc. In a June 28, 2000 interpretation memorandum addressed to Mr. Kenneth Gerecke of Region III (revised), DEP stated that the use of corrugated plastic "switchbox" covers that have not been approved in accordance with general industry standards was prohibited. However, you ask if their use is also prohibited in construction.

The SP Products Inc. temporary box cover ("temporary cover") is basically a warning sign made of high-visibility corrugated plastic, and similar to plywood or heavy cardboard in physical appearance. The temporary cover, which attaches to the panel or switch box by two nonconductive magnetic strips, is rated for 600 volts, and is advertised as durable and being water, puncture, and tear resistant. The temporary cover is intended to be used when frequent access is needed to the live electrical parts of a panel box. During those times (involving both construction and general industry activities), the temporary cover would be used in lieu of the permanent (approved) covers provided by switch and panel box manufacturers. SP Products Inc. says the ease with which the temporary cover can be installed and repeatedly moved or removed is a significant advantage over the common practice of using cardboard or plastic sheeting. That practice is common because of the time and effort needed to remove and replace the manufactured cover repeatedly, which typically requires screws or nuts and bolts for its removal and re-installation.

Sections 1926.405(d) and 1910.305(d) require that:


Switchboards that have any exposed live parts shall be located in permanently dry locations and accessible only to qualified persons. Panelboards shall be mounted in cabinets, cutout boxes, or enclosures designed ["approved" for §1910.305] for the purpose and shall be dead front. However, panelboards other than dead front externally operable type are permitted where accessible only to qualified persons... [emphasis added]

Both standards define "accessible" and "readily accessible" as follows:

Accessible (as applied to equipment): Admitting close approach; not guarded by locked doors, elevation, or other effective means. (See "Readily accessible").

Readily accessible: Capable of being reached quickly for operation, renewal, or inspections, without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, chairs, etc.

In essence, the temporary cover is designed to make the live parts of the panel box "readily accessible." With the temporary cover installed, anyone, including unqualified personnel, can readily obtain access to those parts. In contrast, the standards indicate that inaccessibility requires obstacles that are not easily/readily overcome to block access to the live parts. For example, the original, manufacturer-supplied panel box covers can only be removed by first removing screws. Therefore, the temporary cover violates these standards.