Question 1
A multi-wire branch circuit shares a neutral between two 120 V ungrounded conductors from different phases. What is required to ensure safe disconnection?
Question 2
A multiwire branch circuit (MWBC) shares a neutral between two ungrounded conductors. What is a key safety requirement for the disconnecting means of the two ungrounded conductors?
Question 3
A multi-wire branch circuit shares a neutral between two 120 V ungrounded conductors supplied from a 120/240 V panel. The neutral current is unexpectedly high even when the phase currents are similar. Which condition is MOST likely?
Question 4
On a multi-wire branch circuit (MWBC) using a shared neutral, why must the ungrounded conductors be on different phases or legs?
Question 5
A multi-wire branch circuit using a shared neutral must have ungrounded conductors that are:
Question 6
Which conductor material is most commonly used for small residential branch circuits in Canadian dwellings?
Question 7
On a complex lighting and receptacle plan, you must identify circuits that share a neutral conductor in a multi-wire branch circuit. What feature on the drawings or panel schedule helps most with this task?
Question 8
In a multi-wire branch circuit using a shared neutral, what condition must be met to avoid overloading the neutral conductor?
Question 9
During an inspection of an older building, you find a multi-wire branch circuit where the two ungrounded conductors land on breakers that do not have a common disconnecting handle. What is the main safety concern?
Question 10
Which cable type is most commonly used for residential interior branch circuits in wood-frame construction in Canada?
Question 11
Which cable type is commonly used for residential interior wiring for general-purpose branch circuits in Canada?
Question 12
You find multiple neutrals landed under one terminal on a neutral bar that is not listed for more than one conductor. What should you do?
Question 13
A multi-wire branch circuit shares a neutral between two hot conductors. For safety, how should the breakers for these hots be arranged?
Question 14
In a mixed-use building, the owner requests that receptacle circuits from different tenants share neutrals in the same raceway. What is the most important concern?
Question 15
Which statement best describes a multi-wire branch circuit (MWBC) in a dwelling unit?
Question 16
A multi-wire branch circuit feeds two small-appliance circuits in a kitchen. What must be true about the two-pole breaker or handle tie protecting this MWBC?
Question 17
In a multiwire branch circuit (MWBC) using a shared neutral, what is one key requirement for the ungrounded conductors?
Question 18
An intermittent tripping of a GFCI receptacle occurs whenever two circuits that share a neutral are both heavily loaded. What is a likely cause?
Question 19
During service work, an electrician finds that a neutral conductor for a multi-wire branch circuit is loose. What is the MOST likely symptom on the connected 120 V loads?
Question 20
A commercial office panelboard is supplied by a 208Y/120 volt, 3 phase, 4 wire system. Several 120 volt receptacle loads are fed using multiwire branch circuits with shared neutrals. An apprentice measures significant neutral current even when some hot conductors are lightly loaded. What wiring issue could cause this?
Question 21
A shared neutral multiwire branch circuit (MWBC) is installed using two hot legs from a 120/240 V system. What is important for the breakers serving these hot legs?
Question 22
A multiwire branch circuit supplies two 120 V small-appliance circuits using a shared neutral. After replacing the panelboard, the two ungrounded conductors were landed on different single-pole AFCI breakers on the same phase. The shared neutral remains in place. What symptom is most likely when loads are plugged in?
Question 23
A multi-wire branch circuit (MWBC) shares a neutral between two ungrounded conductors on opposite phases. Which panel arrangement is acceptable?
Question 24
A large panelboard has several multi-wire branch circuits. Neutrals for different circuits have been tied together under one terminal. What is the main hazard of this practice?
Question 25
A panelboard in a commercial building has neutrals and equipment grounding conductors landed under the same terminal screws. What is the most appropriate corrective action?
Question 26
A 120/240 V single-phase service has several multiwire branch circuits. One multiwire branch circuit has a shared neutral between two ungrounded conductors on the same phase. What is the primary concern with this condition?
Question 27
In a commercial building retrofit, LED drivers are being installed to replace older fluorescent ballasts. The electrician notices that neutral conductors are shared among several circuits. What is the most critical consideration when reusing these neutrals?
Question 28
A multiwire branch circuit shares a neutral between two 120 V ungrounded conductors on opposite legs of a 120/240 V service. If one ungrounded conductor is incorrectly moved to the same phase as the other, what is the MOST likely result?
Question 29
When multiple branch circuits share a neutral conductor (multi-wire branch circuit), what is generally required at the breakers?
Question 30
On a multi-wire branch circuit, what is a common symptom of an open shared neutral?