511 EM 385-1-1 Chapters 9-15

Sections

11-8. General Requirements.

Attachment Plugs and Receptacles

Use listed equipment for portable electric tools or cords in conductive locations such as water-filled areas.
Ensure attachment plugs endure rough use and have strain relief to protect terminal screws.
Connect plugs into receptacles over 240 volts only when the circuit is de-energized, or specific conditions like integral disconnects, local disconnects, or RCD protection are met.

Clear Spaces

Maintain a clear space of 24 inches (15 inches for cranes) around electrical equipment to ensure safe access and operation.
Implement procedures to maintain clearance and ensure safe escape in spaces where standard clearance is not feasible.

Labeling

Clearly mark switches, fuses, and circuit breakers for easy identification of their respective circuits or equipment.
Label switchboxes, receptacle boxes, and other electrical enclosures to indicate system voltage.

Motors and Controllers

Provide insulating mats or platforms for motors or controllers over 150V, ensuring safety for attendants during operation.

Knowledge Check Choose the best answer for the question.

11-11. To ensure safe access and operation, maintain a clear space of _____ around electrical equipment .

24 inches (15 inches for cranes)

36 inches (4 feet for cranes)

48 inches (6 feet for all other equipment)

6 feet (8 feet for heavy equipment)

You forgot to answer the question!

EM 385-1-1 Paragraph 11-8 (h.–k.).

11-8. General Requirements (h.–k.).

h.  Attachment Plugs and Receptacles.  (11-8.h)

(1)  When portable electric equipment or flexible cords are used in highly conductive work locations, such as those inundated with water or other conductive liquids, listed equipment must be used.

(2)  Attachment plugs for use in work areas must be constructed so that they will endure rough use and must be equipped with a strain relief to prevent strain on the terminal screws.

(3)  Physical attachment of plugs into receptacles rated over 240 volts must be made with the circuit de-energized according to chapter 12 unless one of the following conditions are met:

(a)  The cord connected load has been switched to the off position, unloading the circuit and the plug or receptacle is de-energized by design with an integral disconnect, before electrical contact is made.

(b)  The receptacle is de-energized by local disconnect which is considered under the sole control of the individual attaching the plug.

(c)  The receptable is protected by a residual current device (RCD) set to open at currents not exceeding 30 milliamps and a trip time of 400 milliseconds.

(4)  When a NEMA standard configuration exists for a particular voltage, amperage, frequency, or type of current, the NEMA standard plug and receptacle must be used. When NEMA standard configurations do not exist, such as OCONUS, standard plug and receptacle pairs must be rated for the particular voltage configuration, amperage, frequency, type of voltage, and appropriately listed.

i.  Clear Spaces. Provide and maintain access to, and egress from, working space around all electrical equipment to permit ready and safe operation and maintenance according to NFPA 70, Spaces About Electrical Equipment.  Open equipment doors must not impede access to and egress from the working space.  A space of 24” (15” on cranes) must be the minimum distance required when one or more doors are open for access or egress to not be considered impeded.  Where required clearance is not feasible (for example, floating plant, vessels), establish procedures to ensure sufficient clearance is maintained for fully opening the door and/or servicing the electrical enclosure so that personnel can escape upon an arc flash event.  (11-8.i)

j.  Labeling. The following equipment must be labeled or marked as indicated at a minimum. Other labeling or marking requirements and the means and methods of acceptable application and construction of the labels or markings may be required by other paragraphs of this manual or by documents referenced by this manual that are required to be adhered to.  (11-8.j)

(1)  Mark, label, or arrange all switches, fuses, and automatic circuit breakers for ready identification of the circuits or equipment that they supply.

(2)  Mark switchboxes, receptacle boxes, metal cabinets, enclosures around equipment, and temporary power lines to indicate the system voltage.

k.  Motors and Controllers.  Provide insulating mats or platforms where live parts of motors or controllers operating at over 150V to ground are guarded against accidental contact only by location and where adjustment or other attendance may be necessary during the operation of the apparatus so that the attendant cannot readily touch live parts unless standing on the mats or platforms (see 29 CFR 1926.405).  (11-8.k)