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Soldering 2 (1). To calculate the load,add up the number of amps each piece of Light Cutting Up to 1" 3-4 equipment draws and 20 percent. (3). Face shield:Tinted or non-tinted (2). Often equipment is rated in watts. To get amps: (4). Welding hood A=WNA=AmpsV=VoltsW=Watts (5). Leathers:Alone or combination of chaps,gauntlets,jackets,or pants (3). Select wire which is rated for the number of amps to be carried. and (4). Select receptacles,circuit breakers,and fuses which can carry the aprons. load to be applied,plus 20 percent. (6). Gloves:Leather,cotton,rubber,chain-mail. (5). Electric motors may draw up to 6 times their working load at start-up. (7). Aprons:Cotton,rubber,or leather. This surge can cause the circuit breaker to trip or a fuse to blow. The (8). Fire resistant uniforms. surge may last from a few milliseconds to 10 or 20 seconds depending (9). Hard hats or bump caps. on which what equipment the motor is starting. (10).Hearing protection:Earplugs or earmuffs. 4. Disconnect and Overload Protections (11).Respirators and dust masks:Match respirator cartridge to the A. Disconnect or overload devices open the circuit(switch off the power hazardous automatically)if the device is forced to carry more than its'maximum material from which you need protection. load or if excessive heat occurs due to accidental ground,short circuit,or (12).Coverall:Cotton,flame and chemical resistant. an overload. B. The two common devices for this use are fuses and circuit breakers. Select the type which best suits your application. C. Ground Fault Interrupters(GFI) Electrical Safety When receptacles are placed in wet locations ground fault interrupters (GFI)are advisable. GFI's open the circuit when it detects leakage of a 1. General. certain number of milliaperes is advisable.Use GFI's in areas like A. Never work on energized circuits. bathrooms,piers,labs and wash down areas. B. Do not attempt to perform work which should be done by a qualified 5. Grounding electrician. A. All handheld powertools must have a ground.This may have been C. Do not leave appliances and handheld power-tools plugged in if they do provided when the tool is built;if so the tool will have a three-pronged not have over-current devices. plug. Note—For a grounded powerlool to work properly,it must be 2. Definitions. plugged into a(grounded)receptacle. A. Ampere—The unit for measuring the rate of flow electricity. B. All permanently mounted electrical machines such as drills,lathes,mills, B. Conductor—A material through which an electric current can readily and grinders must grounded. travel. Metals are good conductors. Copper and aluminum are very C. Suitable points for grounding are,cold water pipes,buried tanks which good conductors. contain nonflammable materials,and building structures. If none of these C. Current—The total flow past a certain point in a given length of time. are available,a long stake or plate may be driven into the ground. Electric current is measured in amps. D. Grounding wire must be a continuous conductor without splices. Any D. Insulator—A material through which an electric current does not readily connectors placed on the conductor should be done without the use of pass. Some of the best insulators are polystyrene,mica,glass and solder and should be done with the proper tool and workmanship. Poor wood. connections cause high resistance and could result in arcing or E. Resistance—The opposition of a conductor to the flow of electrical due explosion. to"friction'inside of the conductor,measured to ohms. 6. Temporary Wiring F. Volt—The unit for measuring the force that drives current through a A. All temporary wire should be grounded in accordance with the National circuit. It is conceptually similar to pressure in a water pipe line. Electric Code. 3. Electrical Overload B. Ensure that no wiring is exposed. A. Overloaded circuits can generate heat at the point of resistance to ignite C. Temporary lights should have guards to prevent breakage. nearby combustible ideas. D. Walkways and work areas should be kept clear of wiring. B. Before applying a load to a circuit,calculate the load to be applied. E. All splices should have insulation rated equal to that of the wiring.