Code & Regulations
What is the minimum depth required for a direct burial cable in residential areas?
18 inches
Ohm’s Law states that voltage equals current times what?
Resistance
What color is the neutral wire in a typical residential system?
White or gray
What is the standard voltage for residential circuits in the U.S.?
120V and 240V
What type of fire extinguisher is used for electrical fires?
Class C
According to the NEC, how often must conduit be supported?
Every 10 feet and within 3 feet of a junction box
What does the term "power factor" refer to?
The ratio of real power to apparent power in an AC circuit
What type of conduit is approved for wet locations?
PVC or RMC (Rigid Metal Conduit)
How many watts are used by a 15A circuit at 120V?
1,800 watts
What is the minimum PPE required when working on live circuits over 50V?
Safety glasses, gloves, and arc-rated clothing
What NEC article covers grounding and bonding?
Article 250
What is the total resistance of three 6-ohm resistors in parallel?
2 ohms
What is the minimum burial depth for PVC conduit under a driveway?
18 inches
If a kitchen has 5 small appliance circuits, what is the minimum required amperage per NEC?
20 amps each, 100A total load counted at 50% demand factor
What is the purpose of lockout/tagout (LOTO)?
To prevent accidental energization of electrical equipment during maintenance.
What is the maximum number of 12 AWG conductors allowed in a 4x4x2-1/8 inch junction box?
9
In a three-phase system, how do you calculate total power?
P = √3 × Voltage × Current × Power Factor
What is the ampacity of a #10 THHN copper conductor at 75°C?
35 amps
What is the total amperage draw for a 10 kW heater on a 240V circuit?
41.67 amps
What is the maximum voltage allowed in a residential bathroom light fixture?
120V
What is the minimum required working clearance in front of electrical panels rated 600V or less?
36 inches
What is the frequency of AC power in the United States?
60 Hz
What is the primary purpose of a GFCI outlet?
To protect against ground faults by shutting off power when current leakage is detected
What is the demand factor for a residential feeder supplying a 15 kW range?
8 kW + 40% of remaining 7 kW = 10.8 kW
What is the minimum height for an electrical service drop over a residential driveway?
12 feet