FREE E2 Hazardous (Classified) Locations Questions and Answers

Question 1

According to NEC Article 500, a Class I, Division 1 location is a location in which ignitable concentrations of flammable gases or vapors can exist under which condition?

Accepted Answer

Under normal operating conditions.

Answer

Only during equipment maintenance or repair.

Answer

Only in the event of a catastrophic container failure.

Answer

If they are stored in approved containers.

Question 2

In a Class I, Division 1 location, a conduit seal shall be installed within what distance of a terminal or junction box that contains a switch, circuit breaker, or other arcing device?

Accepted Answer

18 inches

Answer

6 inches

Answer

12 inches

Answer

24 inches

Question 3

What does the temperature marking, or 'T-Code', on a piece of equipment used in a hazardous location signify?

Accepted Answer

The maximum surface temperature the equipment will develop.

Answer

The maximum ambient temperature in which the equipment can operate.

Answer

The type of hazardous material it is approved for.

Answer

The time it takes for the equipment to cool down after shutdown.

Question 4

Which of the following wiring methods is permitted in a Class II, Division 1 location?

Accepted Answer

Threaded rigid metal conduit (RMC)

Answer

Electrical metallic tubing (EMT)

Answer

Type MC cable without an overall nonmetallic jacket

Answer

Open wiring on insulators

Question 5

The fundamental principle of an intrinsically safe system as defined in NEC Article 504 is to:

Accepted Answer

Limit the electrical energy to a level below that required to ignite a hazardous atmosphere.

Answer

Contain any explosion within a robust enclosure.

Answer

Purge the enclosure with clean air to prevent hazardous gases from entering.

Answer

Use only non-arcing components.

Question 6

A Class III location is hazardous because of the presence of:

Accepted Answer

Easily ignitable fibers or flyings

Answer

Flammable gases or vapors

Answer

Combustible dust

Answer

Flammable liquids