Rubber Floor Mating

Scotchrap 20-mil-thick polyvinyl chloride (PVC)

maximum safe use voltage and label colors for

tape (manufactured by Minnesota Mining and

insulating gloves approved for Navy use.

Manufacturing Company) should be installed beneath

Before using rubber gloves, you should carefully

the seam. You may also use a 1-foot wide strip of

inspect them for damage or deterioration. To inspect

electrical grade deck covering under rubber- or

rubber gloves for tears, snags, punctures, or leaks that

vinyl-type coverings instead of heat welding vinyl.

are not obvious, hold the glove downward, grasp the

glove cuff, and flip the glove upward to trap air inside

PORTABLE ELECTRIC-POWERED TOOLS

it. Roll or fold the cuff to seal the trapped air inside.

Then, squeeze the inflated glove and inspect it for

damage. For additional information on rubber gloves,

Safety is a very important factor in the use of

refer to NSTM, chapter 300.

portable power tools and cannot be overemphasized.

The hazards associated with the use of portable power

RUBBER FLOOR MATTING

tools are electric shock, cuts, flying particles,

explosions, and so on. You should ensure portable

You must use approved rubber floor matting in

electric-powered tools are clean, properly oiled, and

electrical and electronic spaces to eliminate electrical

in good operating condition. Before you use any

mishaps and afford maximum protection from

portable electrical equipment, you should visually

electrical shock. Mishap investigations often show

examine the attached cable with plug (including

that the floors around electrical and electronic

extension cords, when used) to ensure it is in

equipment had been covered with only general-

satisfactory condition. Replace promptly any cable

purpose black rubber matting. The electrical

that has tears, chafing, or exposed conductors, and any

characteristics of this type of matting do not provide

damaged plug. Use an approved tool tester or

adequate insulation to protect against electrical shock.

multimeter to test portable electrical equipment with

There are various types of electrical grade mats or

its associated extension cord connected. When using

sheet coverings that conform to the requirements

the multimeter to check continuity of the ground

set forth in Military Specification (MILSPEC)

conductor from the tool case to the dummy receptacle,

MIL-M-15562.

be sure the meter reading is less than 1 ohm. With the

multimeter still connected between the tool case and

To ensure the matting is completely safe, you must

ground, bend or flex the cable to see if the meter

promptly remove from the matting surfaces all foreign

resistance remains 1 ohm or less. If the resistance

substances that could contaminate or impair its

varies, you might have broken conductors in the cord

dielectric properties. The dielectric properties of

or loose connections.

matting can be impaired or destroyed by oil, imbedded

metal chips, cracks, holes, or other defects.

Other safe practices in the use of portable

electric-powered tools include the following:

If the matting is defective for any reason, cover

the affected area with a new piece of matting.

Before you use a tool, inspect the tool cord and

Cementing the matting to the deck is not required, but

plug. Do not use the tool if the cord is frayed or

is strongly recommended. This prevents removal of

its plug is damaged or broken. Never use

the mat for inspection and cleaning, which would

spliced cables, except in an emergency.

leave the area unprotected. If the mat is not cemented,

Before you use a tool, arrange the portable

stencil an outline of the proposed mat on the deck.

cables so you and others will not trip over them.

Inside the mat outline, stencil "ELECTRIC-GRADE

The length of extension cords used with port-

MAT REQUIRED WITHIN MARKED LINES." Use

able tools should not exceed 25 feet. Extension

3/4 inch or larger letters.

cords of 100 feet are authorized on flight and

Electrical insulating deck covering should be

hangar decks. Extension cords of 100 feet are

installed so there are no seams within 3 feet of an

also found in damage control lockers, but are

electrical hazard. Where this is not possible,

labeled FOR EMERGENCY USE ONLY.

thermoplastic deck coverings, such as vinyl sheet

Do not use jury-rigged extension cords that

manufactured by Lonseal, Inc., should be fused

have metal handy boxes on the receptacle ends

chemically, heat welded, or heat fused with a special

hot air gun. With rubber deck coverings, fusing with

of the cord. All extension cords must have

nonconductive plugs and receptacle housings.

heat is not possible. A 3- or 4-inch wide strip of #51

1-16