Applications / CODE

Question 1

Four things to consider when sizing a conductor are:

Answer 1

1: Load in amperes
2: Continuous load or not
3: Termination temperature of equipment
4: Environmental conditions

Question 2

If not connecting directly to equipment, what is the distance from equipment where the termination temperature is no longer a factor in sizing a conductor?

Answer 2

1.2 meters

Question 3

Do neutral conductors count as a current carrying conductor in a conduit?

Answer 3

No

Question 4

Does the common conductor/identified conductor carry current?

Answer 4

Yes

Question 5

When doing code calculations, always use the _____ temperature rating.

Answer 5

Lowest

Question 6

One conductor from each phase and a neutral must be run in each conduit for parallel in order to _____..

Answer 6

Balance electromagnetic fields around the conductors.

Question 7

When using a derating factor to size a conductor, would you multiply or divide the derating factor in the rated load current? What about for conductor ampacity?

Answer 7

Divide load current, multiply conductor ampacity.

Question 8

What trade term is often used to reference flexible cords?

Answer 8

Cabtire

Question 9

NS75 and NS90 are examples of _____. Where will you find allowable ampacity for aluminum and for copper?

Answer 9

Neutral Supported Cable. Table 36A for aluminum, 36B for copper.

Question 10

Note 2 of table 36B lists corresponding correction factors for _____.

Answer 10

Ampacity of copper neutral supported cables.

Question 11

Most electronic loads including computers and dimmers are _____ loads.

Answer 11

Non linear

Question 12

You may downsize the size of a neutral conductor to a demand of _____ if the max unbalanced load is greater than _____.. In what situation can you not do this and why?

Answer 12

70%

200A

Electric discharge lighting or non-linear loads on 3phase 4wire systems, due to harmonic currents.

Question 13

Rule 4-018 states that the service neutral shall not be smaller than the _____ required for the installation.

Answer 13

Grounded conductor

Question 14

What is an issue with single conductor metal sheathed cables?

Answer 14

Magnetic field expanding beyond the metallic armour, which can induce voltage into the sheath.

Question 15

What may be done if sheath currents can’t be eliminated? Per what rule?

Answer 15

Derate the ampacity per rule 2-030

Question 16

When calculating distance correction factor, you would use the (rated values, or termination temperature values) to make the calculation?

Answer 16

Rated values

Question 17

Formula for total distance allowable from OC devices when calculating voltage drop is:

Answer 17

(D3 distance) x (% V drop) x (DCF) x (Vapp/120) = Total distance

Question 18

What’s the difference between transient voltages and ground faults?

Answer 18

Transient voltages seek ground (example, lightening).

Ground faults seek path of least impedance to the source.

Question 19

The ampacities shown in tables D8A to D11A have been determined using the _____, as applied by IEEE 835

Answer 19

Neher-McGrath methodology

Question 20

What is an auxillary gutter?

Answer 20

Raceway of sheet metal enclosure used to supplement wiring space of electrical equipment and enclose interconnecting conductors.