DE Electrician cheat sheet

Delaware licenses electricians through the Board of Electrical Examiners under the Division of Professional Regulation; the license types are Master Electrician, Journeyperson Electrician, and Limited Electrician (with apprentice registration separate).

Master Electrician applicants must document substantial qualifying field experience (commonly cited as 7 years of practical experience, with approved training substituting for part of it) and pass the Delaware master examination.

Journeyperson applicants typically need about 4 years of documented experience under a licensed electrician plus a passing journeyperson exam score; experience letters must be verifiable and on file before the exam.

The Delaware electrician examination is administered by a contracted testing vendor; approval from the Board must be obtained before scheduling, and passing scores are reported to the Board by the vendor.

Delaware requires continuing education for license renewal; licensees must complete the Board-specified hours per renewal cycle, and CE providers/courses must be Board-approved to count.

Licenses renew on a fixed cycle set by the Board; late renewal triggers a penalty fee, and practicing on an expired or lapsed license is a violation subject to disciplinary action.

An applicant must disclose criminal history and any prior license discipline; the Board reviews each case and may deny or condition licensure based on the facts.

Delaware issues a Limited Electrician license for restricted scope work; the scope limits what the holder may install or service, and work outside that scope requires a master or journeyperson.

A licensed master electrician is the party responsible for obtaining electrical permits and for the code-compliant performance of work done under that license, including work by employees.

Ohm's law: E = I × R; I = E ÷ R; R = E ÷ I. Applies to DC circuits and to AC circuits where impedance is purely resistive.

Power in a resistive circuit: P = E × I = I²R = E² ÷ R. In AC circuits, real power P = E × I × power factor.

Series circuit rules: current is the same through every element, voltage divides in proportion to resistance, and total resistance is the sum of individual resistances.

Parallel circuit rules: voltage is the same across every branch, branch currents sum to total current, and total resistance is less than the smallest branch resistance (1/RT = 1/R1 + 1/R2 + ...).

AC impedance combines resistance and reactance: Z = √(R² + X²); inductive reactance XL = 2πfL, capacitive reactance XC = 1 ÷ (2πfC).

Three-phase power: P = √3 × E × I × power factor for a balanced load; single-phase 240 V loads draw half the current of the same kVA at 120 V.

Ampacity and voltage drop: voltage drop in a conductor is Vd = 2 × I × R × L for single-phase two-wire circuits (multiply by √3 for three-phase), and excessive drop reduces delivered voltage.

Conductor resistance rises with temperature and with length, and falls with increased cross-sectional area; skin effect pushes AC current toward the conductor surface at high frequency.

Transformer action: primary-to-secondary voltage ratio equals turns ratio; power in equals power out (minus losses), so a step-down in voltage is a step-up in current.

Article 100 definitions control: a branch circuit is the circuit conductors between the final overcurrent device and the outlets; a feeder runs from service equipment to the final branch-circuit overcurrent device.

Continuous loads are calculated at 125% of the load for overcurrent device and conductor sizing (NEC 210.19 and 210.20), and the 80% rule applies to the continuous-load portion of a circuit.

Standard overcurrent device ratings are 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400 A and upward; the next-higher standard rating may be used only where permitted by 240.4.

Working clearances at electrical equipment are governed by NEC 110.26: 36 in deep for 0–150 V to ground, 42 in for 151–600 V, and 48 in for higher voltages, with 30 in wide clear space and 6 ft 6 in of headroom.

GFCI protection is required in bathrooms, garages, outdoors, kitchens (countertop receptacles), laundry areas, unfinished basements, and other locations listed in 210.8; AFCI protection is required for most 120 V branch circuits in dwelling units per 210.12.

Receptacle spacing in dwelling units: not more than 12 ft apart along the wall, and no point on the wall more than 6 ft from a receptacle (210.52).

Equipment grounding conductors must be sized per NEC 250.122 based on the rating of the overcurrent device protecting the circuit, not on the circuit conductor size.

Box fill is calculated per NEC 314.16 by counting conductor volumes, device yokes, and clamps against the cubic-inch capacity of the box.

The NEC is adopted locally by cycle; Delaware jurisdictions enforce the adopted edition, and local amendments may be stricter than the model code, so always confirm the edition in force.

Cable and raceway support: NM cable must be secured within 12 in of boxes and supported every 4.5 ft; EMT must be supported within 3 ft of boxes and every 10 ft.

Bending radius and conduit fill: use the NEC Chapter 9 tables and Annex C for fill, and keep bends within the raceway's permitted radius to avoid conductor damage.

Conductor identification: grounded conductor is white or gray, equipment grounding conductor is green, green with yellow stripe, or bare, and ungrounded conductors are other colors; the high-leg of a 4-wire delta is orange.

Terminations must be made with listed connectors and torqued to the manufacturer's specification; aluminum conductors require AL-rated devices and oxide-inhibiting compound where specified.

Panelboard installation: neutrals and grounds are bonded only at the service (main bonding jumper); in subpanels the neutral bar must be isolated from the enclosure and grounding bar.

Grounding electrode system: a ground rod must be 8 ft in contact with soil and supplemented by an additional electrode unless a single electrode has 25 ohms or less resistance (250.53).

Motor branch circuits use Article 430: overload protection is sized to the motor nameplate, while short-circuit and ground-fault protection is sized from Table 430.52 percentages.

Wiring methods in wet or damp locations require listed wet-location fittings and conductors; boxes in wet locations must be listed for the purpose and arranged to drain.

Lockout/tagout: de-energize, verify with a tester rated for the voltage, apply a lock and tag, and treat circuits as energized until tested and proven dead.

NFPA 70E establishes approach boundaries: the limited approach boundary restricts unqualified persons, and the restricted approach boundary requires qualified persons with appropriate PPE.

Arc-rated PPE and clothing are selected from an incident-energy analysis or the PPE category tables in NFPA 70E, matched to the available fault current and clearing time.

Personal protective equipment for electrical work includes voltage-rated gloves with leather protectors, arc-rated face protection, and insulated tools rated for the voltage involved.

Temporary power and GFCI protection: receptacles used for construction must have GFCI protection, and extension cords must be listed, undamaged, and rated for the load.

Inspection sequence: rough-in inspection before concealment, then final inspection after devices and equipment are installed and labeled; the authority having jurisdiction may require corrections before energizing.

A permit and inspection are required for new services, panel changes, and major circuit additions; work performed without a permit can be ordered removed or re-inspected at the owner's cost.

Test instruments must be rated for the category of the circuit being tested (CAT III or CAT IV for service and distribution work); using an under-rated meter risks arc flash.

Electrical work in Delaware is permitted and inspected at the local level (city or county) or by the state where no local authority exists; the authority having jurisdiction enforces the adopted code edition.

Permit applications typically require the licensed contractor's name and license number, a scope description, and payment of fees before work begins.

Inspection failures generate a correction notice; the contractor must correct the listed items and request a re-inspection, and repeated failures may trigger additional fees or Board referral.

Unlicensed contracting is enforceable by the Board and local authorities; penalties can include fines, stop-work orders, and denial of future licensure.

Delaware requires the license to be displayed or available and the license number to appear on advertisements and contracts as required by Board regulation.

Code adoption in Delaware follows the state's adoption cycle; local jurisdictions may adopt a different NEC edition or add amendments, so confirm the edition with the AHJ before design.

The Board can discipline a licensee for code violations, failure to obtain permits, abandonment of work, or fraud; discipline ranges from reprimand to revocation and civil penalty.

General lighting load for dwellings is 3 VA per square foot; small-appliance and laundry branch circuits are 1,500 VA each, subject to demand factors in Table 220.42.

Standard method service calculation: sum general lighting, small appliance, laundry, and appliance loads, apply demand factors, then add the largest motor at 25% and compare with the service rating.

Optional method for dwellings (Article 220 Part IV) uses the larger of 100% of the first 10 kVA plus 40% of the remainder of general loads, or the nameplate-based calculation.

Fixed appliance loads are taken at nameplate rating; four or more appliances may use the 75% demand factor where the conditions of 220.53 are met.

Range and dryer loads use Table 220.55 demand factors rather than simple addition when multiple units are supplied by one feeder.

Service and feeder conductors are sized to the calculated load and then checked against the overcurrent device; the neutral load may be reduced per 220.61.

Ampacity adjustments: apply Table 310.15(B)(2)(a) for ambient temperature and Table 310.15(B)(3)(a) for more than three current-carrying conductors in a raceway.

System grounding: the service neutral is grounded at the service disconnect through the main bonding jumper, creating the low-impedance fault path required for overcurrent devices to operate.

Grounding electrode conductor sizing follows Table 250.66 based on the largest ungrounded service conductor; equipment grounding conductors follow Table 250.122 based on the overcurrent device rating.

Bonding jumpers around water meters, gas piping, and structural steel keep metallic systems at the same potential and prevent arcing during faults.

Separately derived systems require their own grounding electrode and bonding jumper, with the neutral-to-ground bond made at the source and not repeated downstream.

Overcurrent devices protect conductors from overload and short circuit; the conductor ampacity must be at least the device rating except where 240.4(E) or (G) permits tap or motor exceptions.

Fuses and circuit breakers must be selected for the available fault current; a device with an interrupting rating below the available fault current can fail catastrophically.

Series-rated systems are permitted only where the combination is listed and marked; replacing a component with an unlisted device voids the rating.

Motor full-load current comes from NEC Tables 430.247 through 430.250 by horsepower and voltage, not from the nameplate, for conductor and protection sizing.

Motor overload protection is based on the nameplate service factor and temperature rise; running overload devices are typically sized at 115%–125% of nameplate current per 430.32.

Short-circuit and ground-fault protection for motors uses Table 430.52 percentages of full-load current, with the next standard size permitted if the calculated value does not correspond to a standard rating.

Motor disconnecting means must be within sight of the controller and motor, or capable of being locked open where not within sight (430.102).

Controllers must be sized to the motor horsepower and voltage, and the disconnect must be rated for at least 115% of the motor full-load current.

HVAC equipment uses Article 440: the nameplate minimum circuit ampacity sizes the conductors, and the maximum overcurrent device rating protects the equipment.

Fire pump, elevator, and emergency system circuits have special requirements in Articles 695, 620, and 700 that override general wiring rules.

NM-B cable is permitted in dwellings but not in wet locations, in masonry, or where subject to physical damage; it must be protected by conduit where exposed to damage.

EMT is permitted in dry and wet locations with listed fittings; it requires support within 3 ft of a box and every 10 ft, and must be reamed to protect conductor insulation.

PVC conduit expands with temperature; expansion fittings are required for long runs, and PVC is not permitted in hazardous locations where the code restricts it.

Liquidtight flexible metal conduit is permitted in wet locations with listed fittings and is commonly used for motor connections; it must be supported per 350.30.

MC cable and AC cable have different grounding means: MC has a separate equipment grounding conductor, while AC uses the armor as the grounding path with a bonding strip.

Raceway fill limits: 53% for one conductor, 31% for two, and 40% for three or more conductors in a raceway, per Chapter 9 Table 1.

Boxes must be accessible; junction boxes cannot be buried in walls or ceilings, and covers must be installed to protect the enclosure.

Class I locations contain flammable gases or vapors; Division 1 is where the hazard exists under normal conditions, Division 2 where it exists only under abnormal conditions.

Class II locations contain combustible dust, and Class III locations contain ignitable fibers; each class has its own grouping and temperature requirements in Articles 500–506.

Zone classifications (Zone 0, 1, 2 for gas; Zone 20, 21, 22 for dust) are an alternative international-style system; equipment must be marked for the zone and gas group.

Intrinsically safe circuits limit energy so that no spark can ignite the atmosphere; they must be separated from other circuits and identified per Article 504.

Equipment in classified locations must be marked with its class, division or zone, and gas or dust group; substituting unmarked equipment is a code violation.

Bathrooms, swimming pools, and fountains have specific bonding and GFCI requirements; pool bonding must connect all metal parts and the water per Article 680.

Emergency systems and legally required standby systems must be separate from normal wiring and tested periodically per Articles 700 and 701.

Box fill counting: each current-carrying conductor counts as one volume, each device yoke counts as two conductor volumes, and each clamp counts as one, unless the box is marked otherwise.

Receptacles in dwelling units must be tamper-resistant where required by 406.12, and all receptacles must be grounded and listed for the application.

Switch and receptacle mounting heights are not fixed by the NEC but are set by local practice or the project specification; verify with the AHJ or drawings.

Boxes must be supported independently of the raceway or cable unless the box is listed for support by the raceway; a box must be rigidly and securely fastened.

Device boxes in walls must be flush with or project slightly from the finished surface; gaps larger than 1/8 in require a listed extension ring or spacer.

Luminaires must be listed and installed per the manufacturer's instructions; recessed fixtures require thermal protection and clearance from insulation as marked.

Appliances and equipment must be installed per their listing and instructions, and disconnects must be within sight where the code requires them.