Question

What is the minimum number of 20-amp 277-volt branch circuits required where 810 incandescent luminaires are to be installed

Answer 1

Complete Question

What is the minimum number of 20-amp 277-volt branch circuits required where 810 incandescent luminaries are to be installed?The lamps to be installed are rated 75 watts at 277 volts. This is NOT a continuous load so each circuit can carry 20 amps maximum

Answer:

The number is
`k = 11`

Step-by-step explanation:

From the question we are told that

The current is
`I = 20 \ A`

The voltage is
`V = 277 \ volt`

The power rating of each bulb is
`P = 75 \ W`

The total number of incandescent luminaries is
`n = 810`

Generally the amount of current each lamp takes is mathematically represented as

`I_e = (P)/( V)`

=>
`I_e = (75)/( 277)`

=>
`I_e = 0.270 \ A`

Generally the number of bulb fitting(i.e bulbs ) a 20 A current can supply (i.e the bulbs the branch ) to is

`N = (I)/(I_e)`

=>
`N = (20 )/( 0.270 )`

=>
`N = 73.86`

Generally the number of 20-amp 277-volt branch circuits required is mathematically represented as

`k = (n)/(N)`

=>
`k = (810)/(73.86)`

=>
`k = 11`