Quiz on the Code

Class 4 Circuits

1. For a Class 4 circuit,  a transmitter shall interrupt an energized circuit when which of these conditions occur on the circuit between the transmitter and receiver?

(a) A ground-fault condition that presents an unacceptable risk of fire or electric shock.
(b) A line-to-line fault condition that presents an unacceptable risk of fire or electric shock
(c) Any other condition that presents an unacceptable risk of fire or electric shock
(d)  any of these

2. Class 4 circuits must be supplied from a power source (transmitter) that has a voltage output of not more than _________ volts peak or dc.

(a) 450
(b) 400
(c) 425
(d) 250

3. When considering the marking on cables for Class 4 Circuits, which one of these measurements is not permitted to appear on the cable?

(a) ampere rating
(b) temperature rating
(c) voltage rating
(d) all are required

4. For conductors sized 24 AWG to 17 AWG, the Class 4 cable shall be marked for _______.

(a) maximum voltage
(b) intended ampacity
(c) length increments
(d) all the above

5. Jacketed cables of Class 4 circuits are permitted in the same enclosure, cable tray, raceway, or cable routing assembly with jacketed cables of any of the following:

(a) NM cable
(b) power limited security system conductors
(c) fiber optic cables
(d) all the above

 

KEY

1. D  ref: 726.121(A)
2. A  ref: 726. 121
3. C  ref: 722.(B)(7)
4. B  ref: 726.144
5. C  ref: 726.139(C)(2)