Red Seal Construction Electrician cheat sheet

Lockout/tagout requires isolating the energy source, applying a personal lock and tag, and verifying absence of voltage before work; only the person who applied a lock removes it.

Arc flash boundary: the distance at which incident energy equals 1.2 cal/cm2 (5 J/cm2); the limited approach boundary restricts unqualified persons from approaching live parts.

CSA Z462 and NFPA 70E set arc-rated clothing requirements: Category 1 needs 4 cal/cm2, Category 2 needs 8 cal/cm2, Category 3 needs 25 cal/cm2, Category 4 needs 40 cal/cm2.

Working space about electrical equipment per CEC Table 2: 750 V to 30 kV to ground requires 2.8 m depth for exposed live parts on one side, 3.0 m for live parts on both sides.

Confined space entry requires atmospheric testing (oxygen 19.5-23%, LEL below 10%, H2S below 10 ppm) before and during entry.

Class C fires involve energized electrical equipment; use CO2 or dry chemical extinguishers, never water or foam.

Minimum approach distances for unqualified persons to exposed live parts at 750 V or less: 1.0 m (CEC Rule 2-304).

Stored energy sources include capacitors, UPS batteries, and pneumatic/hydraulic accumulators; discharge and block them before servicing.

Ohm's law: E = I x R; power P = E x I = I squared x R = E squared / R.

Three-phase power: P = sqrt(3) x E(line) x I(line) x power factor; single-phase: P = E x I x PF.

Impedance Z = sqrt(R squared + X squared); reactance XL = 2 x pi x f x L, XC = 1 / (2 x pi x f x C).

Voltage drop single-phase: VD = 2 x K x I x L / CM (K = 12.9 for copper, 21.2 for aluminum); three-phase uses 1.732 instead of 2.

Conductor resistance rises with temperature: R2 = R1 x (234.5 + T2) / (234.5 + T1) for copper.

Series circuit: same current through all elements, voltages add; parallel circuit: same voltage across branches, currents add.

Power factor correction: kVAR required = kW x (tan of angle 1 minus tan of angle 2).

Transformer turns ratio: E(primary) / E(secondary) = N(primary) / N(secondary); current ratio is inverse.

CEC Rule 8-104 limits continuous load to 80% of overcurrent device rating unless the assembly is rated for 100% loading.

CEC Rule 26-700: receptacles within 1.5 m of a sink require GFCI protection; Rule 26-722 covers bathroom receptacles.

CEC Table 2 sets working space; CEC Table 3 sets allowable ampacities for copper and aluminum conductors in free air and raceway.

Rule 12-3000 requires bonding of all non-current-carrying metal parts; Rule 10-700 covers grounding electrode requirements.

Section 16 governs Class I, II, III hazardous locations; Zone and Division systems both appear in the CEC.

Rule 6-112 requires a disconnecting means within sight of and not more than 9 m from the equipment it controls.

Permit and inspection requirements are set provincially; the electrical contractor must obtain permits before concealed work is covered.

Rule 4-004 sets ampacity correction for ambient temperature and conductor bundling (Table 5A/5B derating factors).

A multimeter measures voltage, resistance, and current; verify the meter's CAT rating (CAT III or IV) matches the environment before use.

A clamp-on ammeter reads current by transformer action around a single conductor; it cannot read current in a two-wire cable without splitting the conductors.

A megohmmeter tests insulation resistance at 500 V or 1000 V DC; minimum acceptable value for a 600 V circuit per CEC is 1 megohm (Rule 44-600).

Continuity testers with a low-voltage source verify bonding and grounding paths; never use an ohmmeter on an energized circuit.

A phase rotation meter confirms the sequence of a three-phase supply before connecting a motor.

Torque wrenches must be calibrated and used on all terminations; CEC requires terminations torqued to manufacturer's marked values.

A receptacle tester confirms wiring polarity and ground presence but does not verify GFCI trip time; use a GFCI tester for that.

Non-contact voltage testers are indicators only; confirm de-energization with a contact meter rated for the voltage.

CEC Rule 12-1000 sets conduit fill: no more than 40% of the interior cross-sectional area for three or more conductors.

Minimum conduit size for a given conductor count is found in CEC Tables 6, 8, and 9.

Bending radius for armoured cable must be at least 6 times the cable diameter; for non-metallic sheathed cable, 3 times.

Support intervals: EMT every 3 m and within 1 m of boxes; rigid metal conduit every 3 m; flexible conduit every 1.5 m.

Rule 12-510 requires a maximum of 360 degrees of bends between pull points in a raceway.

Box fill is calculated per CEC Table 22 and Rule 12-3034; each conductor counts, plus clamps, devices, and grounds.

Cable tray fill per Rule 12-2200; single conductors in tray must be derated per Table 5C.

Expansion fittings are required where raceways cross building expansion joints or where thermal expansion exceeds 6 mm per 30 m.

Service conductor sizing per CEC Rule 8-200 uses demand factors from Section 8; minimum ampacity is 100 A for a single dwelling.

The service disconnecting means must be installed at a readily accessible location, either outside or nearest the point of entry, and must be marked as the service disconnect.

Bonding jumper sizing per CEC Table 16: 200 A service with copper service conductors requires a 6 AWG copper bonding jumper to the water service.

Grounding electrode conductor sizing per Table 16 based on the largest ungrounded service conductor; minimum 6 AWG copper for most residential services.

Separately derived systems require a system bonding jumper at the source and a grounding electrode conductor to the grounding electrode.

A main bonding jumper connects the neutral bus to the enclosure at the service only; downstream panels must have isolated neutral buses.

Ground fault circuit protection requirements: CEC Rule 26-700 covers receptacles near sinks, Rule 26-722 bathrooms, Rule 26-724 outdoor receptacles.

Fault current path impedance determines the time-current trip of the overcurrent device; higher impedance means longer clearing time.

Motor full-load current from CEC Tables 44 and 45; branch circuit conductors sized at 125% of FLC per Rule 28-104.

Overload protection sized per Table 29 based on motor nameplate; running overloads typically set at 115-125% of FLC.

Short-circuit and ground-fault protection per Table 13; inverse-time breakers typically 250% of FLC for standard motors.

Motor disconnecting means must be within sight and not more than 9 m from the motor; a lockable switch is required for motors over 750 W.

Starter types: across-the-line, reduced-voltage (autotransformer, wye-delta, part-winding, soft-start), and VFD.

VFD installation requires shielded motor cable, grounding of the drive enclosure, and attention to reflected wave on long motor leads.

Control circuits per Section 14; a Class 2 control circuit must be separated from Class 1 wiring by barriers or spacing.

Motor rotation reversal: swap any two of the three supply conductors.

Transformer kVA = (sqrt(3) x E x I) / 1000 for three-phase; single-phase kVA = (E x I) / 1000.

Primary and secondary overcurrent protection per CEC Rule 26-250: primary only, primary and secondary, or secondary only with conditions.

Transformer impedance determines available fault current; typical dry-type 75 kVA transformers have 2-4% impedance.

Derating for altitude above 1000 m and ambient above 30 degrees C per manufacturer data and CEC Rule 26-254.

Generator sizing must account for motor starting kVA, step loads, and voltage dip limits (typically 15% maximum).

UPS systems: online double-conversion provides the highest ride-through; line-interactive is less expensive but has transfer time.

Harmonics: 3rd harmonic currents add in the neutral; K-rated transformers and oversized neutrals mitigate the effect.

Standby generator transfer switches must be rated for the load and marked for use as service equipment if applicable.

Lumen method: number of luminaires = (illuminance x area) / (lumens per luminaire x coefficient of utilization x maintenance factor).

Luminaire spacing to mounting height ratio (S/MH) determines uniformity; typical ratios range from 0.8 to 1.5.

Lighting load for a single dwelling is 3 W per square metre minimum for the first 45 m2 per CEC Rule 8-400.

Electric space heating load is calculated at 100% of connected load for the first 10 kW and 75% for the balance in a dwelling.

Low-voltage systems: Class 2 circuits limited to 100 VA; Class 1 remote-control circuits limited to 600 V and require Chapter 3 wiring methods.

Fire alarm systems per CAN/ULC-S524; notification appliance circuits require supervision and end-of-line resistors.

Emergency lighting must provide at least 30 minutes of illumination at 10 lux average along the path of egress.

LED drivers and dimming: 0-10 V analog and DALI digital protocols; verify compatibility with the driver before installation.

Take-off quantities are derived from drawings and specifications; add waste factors (typically 5-10% for cable, 3% for conduit).

Material cost plus labour hours times labour rate plus overhead and profit equals the bid price.

Labour units are expressed in hours per unit; the NECA or Means database provides typical values for rough-in, trim-out, and terminations.

As-built drawings must reflect all field changes; retain for the owner and the authority having jurisdiction.

A change order documents scope changes after contract award and must be priced before execution.

Project schedule uses critical path method; electrical rough-in must precede drywall and follow structural completion.

Load calculations and panel schedules must be submitted for permit review before construction begins.

Closeout documentation includes test results, O&M manuals, warranties, and verification of code compliance.