Special occupancies: Idaho Journeyman Electrician Practice Questions

In the hazardous location system, what separates Class I, Division 1 from Class I, Division 2?

Under 500.5(B), Division 1 locations have ignitible concentrations under normal conditions; Division 2 locations have them only through abnormal events such as leaks or ventilation failure.

A textile mill has easily ignitible fibers and flyings in the air. Which hazardous location class applies?

Section 500.5(D) defines Class III locations by ignitible fibers or flyings; Class I is gases and vapors and Class II is combustible dust.

Gasoline and propane vapors belong to which Class I material group?

Section 500.6(A) places gasoline, propane and similar materials in Group D; acetylene is Group A, hydrogen Group B, and Group E is a Class II (metal dust) group.

Grain dust and flour dust belong to which Class II group?

Section 500.6(B) puts grain, flour, starch, wood and plastic dusts in Group G; Group E is metal dust and Group F is carbonaceous dust such as coal.

What does the temperature class (T-code) marked on hazardous location equipment tell you?

Section 500.8(C) requires a temperature class marking that shows the equipment's maximum surface temperature, which must stay below the autoignition temperature of the gas or dust present.

Which protection technique is typical for equipment in a Class II, Division 1 location?

Section 500.7 lists dust-ignitionproof equipment for Class II, Division 1; explosionproof is the Class I, Division 1 technique and nonincendive is a Division 2 technique.

Threaded conduit joints in a Class I, Division 1 location must be made up with at least how many fully engaged threads?

Section 500.8(E)(1) requires NPT-threaded conduit and fittings to be made wrenchtight with at least five full threads fully engaged.

According to the NEC, what is required in each conduit run that leaves a Class I, Division 1 location?

Section 501.15 requires a sealing fitting in each conduit run that leaves a Class I, Division 1 location, so gases and vapors cannot travel through the conduit into the unclassified area.

In Class I, Division 1, how close to an enclosure containing arcing devices must the conduit seal be?

Section 501.15(A)(1) requires seals within 18 in (450 mm) of enclosures that contain arcing or high-temperature devices.

In a commercial repair garage without the required mechanical ventilation, the area from the floor up to what height is classified Class I, Division 2?

Article 511 classifies the floor area up to 18 in (450 mm) above the floor as Class I, Division 2 in major repair areas where ventilation is not provided, since gasoline vapors are heavier than air.

At a motor fuel dispensing facility, how far from the dispensers must the emergency electrical disconnect be located?

Section 514.11(A) requires readily accessible emergency disconnects not less than 20 ft (6 m) nor more than 100 ft (30 m) from the dispensers they serve.

In a patient care space, how must receptacles and fixed equipment be grounded?

Section 517.13 requires two grounding paths: a wiring method that qualifies as an equipment grounding conductor under 250.118, and an insulated copper equipment grounding conductor.

How many receptacles are required at minimum at each patient bed location in a general care (Category 2) space?

Section 517.18(B) requires at least eight receptacles at each general care patient bed location.

How many receptacles are required at minimum at each patient bed location in a critical care (Category 1) space?

Section 517.19(B) requires at least 14 receptacles at each critical care patient bed location, with at least one connected to the normal system or an unrelated critical branch source as required.

How must a general care (Category 2) patient bed location be supplied?

Section 517.18(A) requires at least two branch circuits at each general care bed: one or more from the critical branch and one or more from the normal system.