E2 Hazardous (Classified) Locations 5

Question 1

Which of the following gases is classified in Group B in Class I hazardous locations?

Accepted Answer

Hydrogen

Answer

Hydrogen is classified in Group B of Class I hazardous locations, along with gases that have similar explosion characteristics.

Question 2

Purged and pressurized enclosures used in hazardous locations must comply with which standard?

Accepted Answer

NFPA 496

Answer

NFPA 496 is the standard for purged and pressurized enclosures for electrical equipment in hazardous locations.

Question 3

In Class I, Division 2 locations, which of the following wiring methods is NOT permitted?

Accepted Answer

Electrical metallic tubing (EMT)

Answer

Electrical metallic tubing (EMT) is not permitted in Class I, Division 2 locations because it uses set-screw or compression fittings that do not provide adequate protection against the hazardous atmosphere.

Question 4

When installing explosion-proof equipment, threaded conduit connections must have a minimum of how many engaged threads?

Accepted Answer

5 threads

Answer

NEC Section 501.10 requires threaded conduit connections to explosion-proof enclosures to have at least 5 fully engaged threads to maintain the explosion-proof integrity of the joint.

Question 5

Which protection concept uses oil immersion to prevent ignition of a surrounding hazardous atmosphere?

Accepted Answer

Oil immersion (Ex o)

Answer

Oil immersion (Ex o) is a protection technique where electrical equipment or parts of equipment are submerged in oil to prevent ignition of the surrounding atmosphere.

(E2) E2 Commercial Electrical Inspector Practice Test

(E2) E2 Commercial Electrical Inspector Practice Test

E2 Hazardous (Classified) Locations 5