Question 151
What is the main purpose of arc-fault circuit interrupter (AFCI) protection in dwelling unit circuits?
Question 152
A 20 A, 120 V branch circuit in a dwelling supplies general-use receptacles. What is the maximum continuous load permitted on this circuit?
Question 153
You are asked to add a new receptacle to an existing 15 A general-purpose branch circuit in a dwelling. The measured existing load at the time is 6 A. Which is the best next step before adding the receptacle?
Question 154
In typical US residential wiring, 14 AWG copper conductors are most commonly used on which size of general lighting and receptacle branch circuit, assuming standard conditions?
Question 155
For general lighting and receptacle loads in a small office, ten duplex receptacle outlets are planned on a 120 V general-use circuit. Using a design value of 180 VA per receptacle, what is the total calculated load?
Question 156
A 15 A, 120 V branch circuit in a home frequently trips when a space heater and a microwave are used at the same time. What is the most appropriate corrective action?
Question 157
For 125 V, 15 A and 20 A receptacle outlets in a dwelling, which of the following locations is recognized as requiring GFCI protection?
Question 158
A multiwire branch circuit feeds a kitchen. Two 120 V small appliance circuits share a neutral but are landed on breakers that are on the same phase with no handle tie. What potential hazard does this create?
Question 159
Which of the following locations most clearly requires a GFCI-protected receptacle in a dwelling unit?
Question 160
A dwelling unit kitchen requires small-appliance branch circuits. What is a common requirement for these circuits in the US?
Question 161
A 14 AWG copper conductor on a 15 A branch circuit in a dwelling is typically protected by which maximum size overcurrent device?
Question 162
When reading a residential plan, the electrical legend shows a symbol for a duplex receptacle with a slash through it. What does this usually indicate?
Question 163
Which common household appliance typically requires a 240 V branch circuit rather than a standard 120 V circuit?
Question 164
A 20 A, 120 V branch circuit supplies general-purpose receptacles in an office. What is the maximum continuous load that should normally be placed on this circuit?
Question 165
In a commercial office build-out, several new cubicles require receptacle circuits. Which factor is MOST important when determining how many receptacles can be placed on a single general-purpose branch circuit?
Question 166
Where is a GFCI-protected receptacle most critically required in a typical dwelling unit bathroom?
Question 167
What is the standard ampere rating of a common duplex receptacle used on general-purpose 120 V branch circuits in US dwellings?
Question 168
What is the minimum conductor size typically used for a 20 A copper general-purpose branch circuit in a US dwelling?
Question 169
Several bathroom receptacles and the garage receptacle in a home have lost power, but all breakers appear on. What should the electrician check first?
Question 170
Which type of protection is typically required for 120 V branch circuits supplying outlets in a bedroom of a new dwelling unit?
Question 171
What is the maximum distance a $120\text{ V}$ non-dwelling unit receptacle is permitted to be from an electric heating unit (e.g., baseboard heater) according to NEC $424.9$?
Question 172
What is the primary purpose of an arc-fault circuit interrupter (AFCI) in dwelling units?
Question 173
What is the primary function of an arc-fault circuit interrupter (AFCI) device in a dwelling unit?
Question 174
A kitchen small-appliance branch circuit serves several countertop receptacles. When a toaster and a coffee maker are used together, the breaker trips. What code-compliant solution is MOST appropriate?
Question 175
An industrial lighting panel frequently experiences nuisance tripping on several 20 A breakers feeding office receptacles and cubicle circuits. Load measurements show each circuit carrying between 18 A and 19 A for several hours at a time. What is the MOST appropriate corrective action?
Question 176
A receptacle labeled 15 A, 125 V is intended for use on which of the following branch circuits in a typical dwelling?
Question 177
A 20 A, 120 V small-appliance branch circuit in a dwelling kitchen is required to supply which of the following?
Question 178
On a residential electrical layout, a receptacle symbol annotated with 'GFCI' most likely indicates:
Question 179
What is the primary function of an arc-fault circuit interrupter (AFCI) in a dwelling unit branch circuit?
Question 180
A cord-and-plug-connected window air conditioner nameplate shows 12 A at 120 V. Which minimum branch-circuit rating is generally appropriate for this load, assuming it is the only load?