Free Low Voltage (C-7) practice test

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10 questions from the Peerless Institute C-7 Low Voltage Systems exam. Covers cable ratings, signal loss, grounding, and code compliance.

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  1. 1Underfloor raceways of half round and flat top raceways, not over 4 inches in width, shall have a covering of concrete or wood over the raceway at least:

  2. 2Dry-type transformers installed indoors, not over 112-1/2 kVA, shall have a separation of at least ____ from combustible materials.

  3. 3Underfloor flat top raceways, 4 inches wide, but not over 8 inches wide, with a spacing of 1 inch or more between raceways shall be covered with concrete to a depth of not less than:

  4. 4If excavating a trench 25 meters x 14 meters x 5 ft., how many cu. yds. are there?(NOTE: There are 3.218 ft. in one meter. The answer is arrived at by the following equation:(25 x 3.218) x (14 x 3.218) x 5 divided by 27 = 697.7 = 672 cu. yds.)

  5. 5A grounding ring encircling the building, in direct contact with the earth, must consist of at least ____ ft. of bare copper conductor not smaller than 2 AWG.

  6. 6The minimum depth of working space for a 120/240 volt panelboard, with exposed live parts on one side and grounded parts on the other, shall be at least:

  7. 7At least 1/4 in. of NM cable, including its sheath, must be brought into a nonmetallic box.

  8. 8Underfloor flat top raceways, 4 inches wide not but not over 8” wide, spaced less than one inch apart shall be covered with concrete to a depth of:

  9. 9Each auto transformer 600 volts, nominal, or less, shall be protected by an individual overcurrent device. This overcurrent device shall be rated or set at not more than ____ percent of the rated full-load input current.

  10. 10The lighting outlets provided for illumination about electrical equipment over 600 volts shall be so arranged that persons changing lamps or making repairs on the ____ will not be endangered by live parts or other equipment.