CEA NEC Code and Calculations 2

Question 1

According to the NEC, what is the maximum voltage drop allowed for a branch circuit serving lighting loads?

Accepted Answer

3%

Answer

The NEC recommends a maximum voltage drop of 3% for branch circuits and 5% total for feeders and branch circuits combined.

Question 2

A 20-ampere, 120-volt branch circuit is limited to what maximum continuous load?

Accepted Answer

16 amperes

Answer

NEC 210.20 requires that continuous loads not exceed 80% of the branch circuit rating, so 20A × 80% = 16A maximum continuous load.

Question 3

What NEC article covers wiring methods and materials for general installations?

Accepted Answer

Article 300

Answer

NEC Article 300 covers general requirements for wiring methods and materials used in electrical installations.

Question 4

When calculating the load for a household electric dryer, the NEC requires a minimum demand of how many volt-amperes?

Accepted Answer

5,000 VA

Answer

NEC 220.54 requires a minimum load of 5,000 VA for each electric dryer when calculating feeder and service loads.

Question 5

Under NEC Article 210, a 15-ampere branch circuit is permitted to serve a maximum of how many general lighting receptacle outlets in a dwelling?

Accepted Answer

No specific limit by count

Answer

The NEC does not limit receptacle outlets by count on a branch circuit; load limits and circuit ampacity govern the design instead.

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