Maine Low Voltage Practice flashcards

34 cards. Read the term and the definition here. The deck at the top of this page is optional.

NEC box fill counting

Each 14, 12, or 10 AWG conductor counts as one volume; each device yoke counts as two; each clamp counts as one; all grounding conductors together count as one.

Working clearance depth

NEC 110.26 requires 3 ft of depth for equipment up to 150 V to ground, 4 ft for 151 to 600 V, and 5 ft above 600 V where live parts are exposed on both sides.

GFCI requirement locations

NEC 210.8 requires GFCI protection for dwelling bathroom, garage, outdoor, unfinished basement, kitchen countertop, and within 6 ft of sink receptacles, among other locations.

Equipment grounding conductor sizing

NEC Table 250.122 sizes the equipment grounding conductor by the rating of the overcurrent device protecting the circuit, not by the ungrounded conductor size.

Conductor ampacity correction

Table 310.16 base ampacity is multiplied by the ambient temperature correction factor and by the adjustment factor for more than three current-carrying conductors in a raceway.

Maine license classes

Maine issues master, journeyman, and limited electrician licenses plus apprentice registration; each class has a defined scope, and limited licenses cover only named categories.

Low-energy license scope

Maine low-energy work covers circuits operating at 50 volts or less and limited-energy systems; line-voltage power wiring requires a journeyman or master license.

Maine continuing education

Maine requires continuing education hours per renewal cycle, including code-update content; the exact hours and cycle length are set by Board rule and should be verified.

Apprentice supervision rule

A Maine apprentice must be registered with the Board and work under the direct supervision of a licensed master or journeyman; the apprentice may not work unsupervised.

Permit before electrical work

A permit is required before installing, altering, or extending electrical wiring; fees and inspection scheduling are set by the local code enforcement officer or state inspector.

Rough-in versus final inspection

Rough-in inspection occurs after boxes and raceways are installed but before concealment; final inspection occurs after devices, fixtures, and panel labeling are complete.

Stop-work order effect

An inspector may issue a stop-work order for unpermitted or unsafe work; work stops until the defect is corrected, and appeals go to the local board of appeals.

Utility service standards

Service conductors, meter sockets, and point-of-delivery rules are set by the serving utility's published standards, which are enforceable in addition to the NEC.

Ohm's law and power

V equals I times R; power P equals V times I, also I squared times R or V squared divided by R. A 1,500 W load at 120 V draws 12.5 A.

Series versus parallel circuits

In series, current is common and voltage divides and resistances add; in parallel, voltage is common, current divides, and total resistance is below the smallest branch.

Three-phase power formula

For a balanced three-phase load, P equals 1.732 times line voltage times line current times power factor; single-phase power is voltage times current times power factor.

Circular mils formula

Circular mils equal the conductor diameter in mils squared; 12 AWG is 6,530 CM, 10 AWG is 10,380 CM, and 8 AWG is 16,510 CM.

Bonding versus grounding

Bonding connects metal parts to create an equipotential fault-current path; grounding connects the system to earth. Bonding clears faults, not the earth connection.

Dwelling receptacle spacing

NEC 210.52(A) requires receptacles so that no point along the floor line in any wall space is more than 6 ft from a receptacle.

Kitchen countertop receptacle spacing

NEC 210.52(C) requires countertop receptacles so no point along the wall line is more than 24 in from a receptacle, with one required per island or peninsula.

Small-appliance branch circuits

At least two 20 A small-appliance branch circuits are required for dwelling kitchen, dining, pantry, and similar areas, and they may not supply lighting outlets.

NM cable support intervals

Nonmetallic-sheathed cable must be secured within 12 in of boxes and at intervals not exceeding 4.5 ft along the run, per NEC 334.30.

Master electrician authority

A Maine master electrician may contract for and supervise electrical work; a journeyman performs electrical work under a master's supervision.

Lapsed license practice

Practicing on a lapsed Maine license is a violation; reinstatement may require a fee and proof of continuing education before the license is restored.

Board disciplinary authority

The Electricians' Examining Board may investigate complaints, hold hearings under the Maine Administrative Procedure Act, and impose fines, suspension, or revocation.

Underground feeder depth

NEC Table 300.5 requires 24 in for direct-buried residential branch circuits at 120/240 V, 18 in for GFCI-protected 120 V residential circuits, and 18 in under concrete.

Available fault current marking

NEC 110.24 requires service equipment to be field-marked with the available fault current and the date the calculation was performed.

Construction site GFCI

NEC 590.6 requires GFCI protection for all 125 V receptacles used on construction sites, and a separate temporary service permit may be required locally.

Voltage divider rule

In a series circuit, the voltage across a resistor equals the source voltage times that resistance divided by total resistance; this explains dimming from a loose neutral.

Megohmmeter insulation test

Insulation resistance is measured with a megohmmeter at a test voltage above the circuit rating; readings below 1 megohm generally indicate moisture or damaged insulation.

Main bonding jumper

NEC 250.28 requires a green screw or listed strap sized by Table 250.102(C)(1) connecting the grounded service conductor to the service equipment enclosure.

Grounding electrode conductor sizing

NEC Table 250.66 sizes the grounding electrode conductor from the largest ungrounded service conductor and never requires more than 3/0 copper or 250 kcmil aluminum.

Weather-resistant receptacles

NEC 406.9 requires listed weather-resistant receptacles in wet outdoor locations with an enclosure that maintains the rating while a cord is plugged in.

Three-way switch common

A three-way switch has one common terminal and two travelers; the common is marked by a different-colored screw and connects to the supply or the fixture leg.