Red Seal Construction Electrician flashcards
Red Seal Construction Electrician · Build recall with a focused review session.
33 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Lockout/tagout verification
- After isolating and locking the energy source, the worker must test for absence of voltage with a meter rated for the system voltage before touching conductors.
- Arc flash boundary
- The distance from live parts at which incident energy equals 1.2 cal/cm2. Inside this boundary, arc-rated PPE is required for the calculated incident energy level.
- Limited approach boundary
- A distance from exposed live parts that unqualified persons may not cross unless escorted by a qualified person. Set by system voltage in CSA Z462.
- Three-phase power formula
- P equals the square root of three times line voltage times line current times power factor. Used to compute load in watts for balanced three-phase circuits.
- Voltage drop calculation
- Single-phase: VD equals 2 times K times current times length divided by circular mils. Three-phase substitutes 1.732 for the factor 2. K is 12.9 for copper.
- Impedance triangle
- Impedance Z equals the square root of resistance squared plus reactance squared. Inductive reactance XL equals 2 pi f L; capacitive reactance is inversely proportional to frequency.
- Power factor correction kVAR
- kVAR required equals kW times the difference between the tangents of the original and target power factor angles. Capacitors supply reactive power locally.
- Continuous load 80 percent rule
- CEC Rule 8-104 limits continuous load to 80 percent of the overcurrent device rating unless the assembly is listed for 100 percent loading.
- Conduit fill 40 percent
- CEC Rule 12-1000 permits conductors to occupy no more than 40 percent of a raceway's interior cross-sectional area when three or more conductors are installed.
- Megohmmeter insulation test
- Applies 500 or 1000 V DC to measure insulation resistance. CEC Rule 44-600 requires a minimum of 1 megohm for circuits rated 600 V or less.
- Clamp ammeter limitation
- A clamp meter reads the net current through its jaws. Placing it around both conductors of a circuit cancels the magnetic fields and reads zero.
- Box fill calculation
- Per CEC Table 22, each conductor, clamp, device, and ground contributes volume. The sum must not exceed the box's marked cubic-centimetre capacity.
- Raceway bend limit
- CEC Rule 12-510 limits a run to 360 degrees of bends between pull points. Additional bends require a junction box or conduit body.
- EMT support spacing
- Electrical metallic tubing must be supported within 1 m of each box and at intervals not exceeding 3 m along the run per CEC Rule 12-1014.
- Service disconnect location
- The service disconnecting means must be readily accessible, installed at or nearest the point of entry, and marked to identify it as the service disconnect.
- Main bonding jumper
- Connects the neutral bus to the service enclosure. It is installed only at the service or separately derived source, never in downstream panels.
- Grounding electrode conductor sizing
- Sized from CEC Table 16 based on the largest ungrounded service conductor. Minimum 6 AWG copper for typical residential services.
- Motor branch circuit sizing
- CEC Rule 28-104 requires branch circuit conductors rated at 125 percent of motor full-load current from Tables 44 and 45.
- Motor overload protection
- Running overloads are set per CEC Table 29, typically 115 to 125 percent of nameplate full-load current, protecting the motor from sustained overcurrent.
- Motor disconnecting means
- Required within sight and not more than 9 m from the motor. Motors over 750 W need a lockable disconnect per CEC Rule 28-600.
- Reversing three-phase motor
- Interchange any two of the three supply conductors at the motor or starter to reverse rotation. This changes phase sequence.
- Transformer kVA formula
- Three-phase kVA equals 1.732 times voltage times current divided by 1000. Single-phase kVA equals voltage times current divided by 1000.
- Transformer overcurrent protection
- CEC Rule 26-250 permits primary-only protection under specified conditions; otherwise primary and secondary protection are both required based on transformer rating.
- Generator sizing for motors
- Generator capacity must accommodate motor starting kVA and limit voltage dip, typically to 15 percent, while carrying the steady connected load.
- Triplen harmonic neutral current
- Third-order harmonic currents from nonlinear loads add arithmetically in the neutral. K-rated transformers and oversized neutrals mitigate overheating.
- Lumen method calculation
- Number of luminaires equals illuminance times area divided by lumens per luminaire times coefficient of utilization times maintenance factor.
- Dwelling lighting load
- CEC Rule 8-400 requires a minimum lighting load of 3 W per square metre for the first 45 square metres of a single dwelling.
- Class 2 circuit limit
- Class 2 circuits are limited to 100 VA and use Chapter 3 wiring methods with separation from Class 1 and power circuits per CEC Section 16.
- Emergency lighting duration
- Emergency lighting must provide at least 30 minutes of illumination at an average of 10 lux along the path of egress.
- Take-off waste factors
- Estimates add waste to measured quantities: typically 5 to 10 percent for cable and about 3 percent for conduit, depending on routing complexity.
- Bid price components
- Material cost plus labour hours times labour rate plus overhead plus profit. Labour units come from estimating databases by installation type.
- Change order purpose
- Documents scope changes after contract award, priced before execution, and signed by both parties to protect the contractor's compensation.
- As-built drawings
- Marked-up drawings reflecting all field changes and deviations from design. Delivered to the owner and retained by the authority having jurisdiction.