AWS Installation Techniques 3 — Questions and Answers
Question 1: When installing shielding gas supply lines for MIG welding, which material is NOT recommended for flexible hose sections?
- Stainless steel braided hose
- Natural rubber hose (Correct answer)
- Nylon-lined hose
- PTFE-lined hose
Correct answer: Natural rubber hose
Natural rubber hose is not recommended for shielding gas lines because it can outgas contaminants that degrade weld quality and may absorb moisture.
Question 2: During the installation of a robotic welding cell, what is the purpose of installing the welding power source outside the cell enclosure?
- To reduce electromagnetic interference with robot controls
- To make the power source easier to service without entering the cell
- To reduce heat buildup inside the cell enclosure
- Both A and B are correct (Correct answer)
Correct answer: Both A and B are correct
Locating the power source outside the robotic cell both reduces electromagnetic interference with sensitive robot controls and allows maintenance without entering the guarded enclosure.
Question 3: What is the maximum recommended distance between the welding power source and the work for SMAW to minimize voltage drop?
- 25 feet total combined cable length
- 100 feet total combined cable length (Correct answer)
- The cable length has no effect on voltage drop
- 50 feet for the electrode lead only
Correct answer: 100 feet total combined cable length
AWS recommends keeping total combined cable length (electrode plus work leads) to 100 feet or less to minimize resistance-related voltage drop and maintain arc quality.
Question 4: When installing a plasma cutting system, where should the air dryer/filter assembly be positioned relative to the plasma unit?
- After the plasma unit on the outlet side
- Immediately before the plasma unit inlet (Correct answer)
- At the main compressor outlet only
- Anywhere along the supply line
Correct answer: Immediately before the plasma unit inlet
The air dryer and filter must be installed immediately before the plasma unit inlet to remove moisture and contaminants as close to the point of use as possible.
Question 5: A TIG welding installation requires a high-frequency arc starter. What electrical installation precaution is mandatory?
- Using aluminum wiring for all connections
- Proper grounding and shielding of nearby electronic equipment and controls (Correct answer)
- Installing the HF unit at least 20 feet from the welder
- Using only rubber-insulated cables throughout
Correct answer: Proper grounding and shielding of nearby electronic equipment and controls
High-frequency arc starters emit electromagnetic interference that can damage or disrupt PLCs, CNC controls, and other electronic equipment if proper shielding and grounding are not installed.
Question 6: What is the correct method for supporting overhead welding cable runs to prevent cable damage and tripping hazards?
- Tie cables directly to structural steel with wire ties
- Support cables with proper cable trays, J-hooks, or messenger wire at regular intervals (Correct answer)
- Bundle cables tightly together with duct tape
- Allow cables to drape in large loops between support points
Correct answer: Support cables with proper cable trays, J-hooks, or messenger wire at regular intervals
Cable trays, J-hooks, or messenger wire provide proper support that prevents cable damage from excessive bending, abrasion, and weight stress.
Question 7: When installing welding equipment in an area classified as a hazardous location (Class I, Division 2), what type of enclosure is required for electrical components?
- Standard NEMA 1 general-purpose enclosure
- Explosion-proof or intrinsically safe enclosure rated for the hazard class (Correct answer)
- Weatherproof NEMA 3R enclosure
- Any enclosure with a lockable door
Correct answer: Explosion-proof or intrinsically safe enclosure rated for the hazard class
Class I, Division 2 hazardous locations require explosion-proof or intrinsically safe equipment enclosures to prevent ignition of flammable gases or vapors.
AWS Installation Techniques 3
When installing shielding gas supply lines for MIG welding, which material is NOT recommended for flexible hose sections?