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Art. 600 — Electric Signs & Outline Lighting

600.5(A)Provide a dedicated branch circuit (typically 20A, 120V) to each sign/outline lighting system—no other loads permitted.
600.6(A)(1)A readily accessible disconnect must be within sight of the sign or outline lighting system unless exceptions apply.
600.3All sign equipment must be listed/identified and installed per the label and instructions (mounting, conductors, environmental limits).
300/600 blendFollow Chapter 3 wiring method rules; use wet/damp-rated fittings where exposed to weather.
Grounding/BondingBond metallic sign enclosures and raceways; maintain a low-impedance fault path back to the source.

EXAM TRAP

If it’s a sign circuit, it’s dedicated. Don’t add receptacles/lighting. Disconnect must be within sight unless a permitted exception is met.

Local disconnect: labeled and readily accessible.

Use listed components and follow markings.

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Art. 620 — Elevators, Escalators, Platform Lifts

620.51Means for disconnecting with lock-open capability for driving machines, controllers, and machinery spaces.
620.22Separate lighting/receptacle circuits from power/drive circuits per 620; don't mix them.
620.53Car-light/receptacle circuits often require GFCI and dedicated supply; check adopted cycle details.
620.37/620.21Use wiring methods identified for the spaces (hoistway, machinery room, pit). Moisture, movement, and service access matter.
LabelingControllers and disconnects must be labeled clearly; AHJ will look for consistency with drawings and O&M docs.

RULE OF THUMB

Keep elevator car lights/recepts separate from drive power. Disconnects must be lockable and located where required.

Lockable disconnect within the room.

Follow controller labeling and 620 specifics.

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Art. 625 — Electric Vehicle Supply Equipment (EVSE)

625.41GFCI/ground-fault protection often integral to EVSE; understand how upstream protection interacts.
625.42EVSE is a continuous load — size conductors and OCPD at 125% of nameplate.
625.44/625.46Follow rules for cord-and-plug vs hard-wired EVSE, cord lengths, and mounting heights.
LabelingPlacards for maximum output/rating and circuit requirements help techs and inspectors verify compliance.
VentilationSome legacy equipment requires ventilation; modern listed EVSE may waive it—check the listing.

NEC REFERENCE

Treat EVSE as continuous. Example: 40A nameplate → 50A breaker (125%) with conductors to match.

Confirm continuous-load sizing and GFCI behavior.

Size to nameplate × 125%.

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Art. 630 — Electric Welders

Duty CycleWelder input current depends on duty cycle; use 630 tables/notes instead of generic branch rules.
OCPDOCPD/conductor sizing can be smaller or larger than standard due to 630 multipliers—follow the table math.
ReceptaclesUse the correct configuration/rating; verify cord caps match receptacle/branch rating.
Feeder ImpactGroups of welders can be diversified per 630; don't oversize blindly.
NameplateWhen in doubt, the nameplate + Article 630 drive the design—don't 'average' ratings.

TABLE

Quick Sheet — Duty Cycle Multipliers

Duty Cycle	Multiplier (≈)	Notes
100%	1.00×	Rated input current
60%	0.80×	Common shop welder example
50%	0.71×	Use Article 630 tables
30%	0.55×	Use Article 630 tables

Use Article 630 nameplate + tables for the exact multiplier, then size OCPD and conductors per 630.

Size branch/OCPD using 630 rules.

Nameplate + 630 tables drive sizing.

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Art. 640 — Audio Systems

640.9Use listed/identified equipment and cable types; support low-voltage per manufacturer and Code.
SeparationMaintain separation between AC power and LV audio/data as required to reduce noise and hazards.
Branch SizingSize power for racks/amps to nameplate; account for ventilation and heat loads.
GroundingBonding/grounding per manufacturer reduces hum and shock risk; avoid bootleg grounds.
ConnectorizationUse proper terminations (barrier strips, speakON, locking inlets) where listed; strain reliefs matter.

CHART

Audio Circuits — Common Topologies

Topology	Description
Line-Level (balanced)	XLR/TRS connections
Line-Level (unbalanced)	RCA connections
Speaker-Level	Amp → speaker direct
Powered Speakers	AC + signal combined

Separate low-voltage signal from AC power where required; follow listings and 640 separation/support rules.

Ventilation and branch sizing matter.

Keep LV and AC separated as specified.

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Art. 645 — IT Equipment Rooms

645.10Provide a disconnecting means for electronic equipment power (and HVAC when 645 rules are used).
SpacesUnderfloor plenums require plenum-rated cable; identify pathways and penetrations correctly.
Fire IntegrationCoordinate with fire detection/suppression; signage and EPO (if used) must be obvious.
Wiring MethodsSupport, secure, and protect cabling per Chapter 3—no free-air spaghetti under raised floors.
DocumentationLabel circuits, racks, and panel schedules; IT changes constantly—make maintenance safe and traceable.

JOBSITE HORROR STORY

A raised-floor job failed when non-plenum data cable went everywhere. Result: rip-out and replace under a production outage window.

Use listed plenum/raised-floor cabling.

Know the shutdown sequence and labeling.

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Art. 680 — Pools, Fountains, Spas

680.21(A)Pool pump motors require GFCI (scope varies by edition); verify local adoption.
680.26Equipotential bonding grid: bond reinforcing steel, metal components, and perimeter surfaces.
680.23Wet-niche luminaires: follow listing for niches, bonding, and transformers (where used).
Wiring MethodsUse corrosion-resistant/wet-location wiring methods; seal fittings where required.
ClearancesRespect setbacks from pools for panels, receptacles, and equipment (distances vary by type).

EXAM TRAP

Equipotential bonding is a make-or-break inspection item. Bond the steel, rails, and deck surfaces properly.

Expect GFCI on pump motors.

Bonding ties metallic parts together.

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Art. 690 — Photovoltaic Systems

690.12Rapid shutdown where required; label boundaries and verify device operation.
690.8(A)/(B)125% current factors for source/outputs; apply temperature correction and conduit fill derating.
690.13/690.15Provide required disconnects for PV equipment and specify locations clearly.
LabelingPlacards at service equipment and PV points of isolation; firefighters rely on these.
GroundingUse listed bonding jumpers/clips for module rails and metallic raceways; continuity is critical.

NEC REFERENCE

Use 125% for PV max current, then apply conditions of use (temperature/derating). Don’t skip the label package.

Placards where first responders expect them.

Mind temperature and grouping corrections.

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Art. 691 — Large-Scale PV (Utility-Scale)

ScopeApplies to utility-scale PV where engineering supervision is assumed; 691 modifies 690 for scale.
Docs/StudiesShort-circuit/coordination studies, relay settings, arc-flash and grounding methods are engineered.
EquipmentMedium-voltage collection, GIS/transformers, and switchgear—follow manufacturer and utility requirements.
GroundingGrounding/bonding systems are designed; soil conditions and corrosion control are addressed in the plan set.
Labeling/AccessAccess control, signage, and emergency response plans scale with the site footprint.

TABLE

Quick Sheet — 690 vs 691

Topic	690 (Building PV)	691 (Utility-Scale)
Scope	Typical building-connected PV	Large utility-scale arrays
Design	Prescriptive methods permitted	Engineered systems/practices
Protection/Coord.	Standard PV OCPD/labels	Utility coordination & engineered protection
Documentation	Placards & one-lines	Detailed documentation & supervision

Use 691 when the project qualifies as utility-scale; otherwise apply 690.

Different scale, different rule structure.

Coordination and documentation drive approvals.

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Art. 695 — Fire Pumps

695.3Reliability: arrange normal and alternate sources for continuity—utility + generator or alternate service.
695.4Feed directly to the fire pump controller with permitted taps; minimize tripping opportunities.
695.5/695.6Overcurrent protection set so the pump keeps running—different than typical feeder protection.
RoutingProtect conductors physically (encased, MI cable, or dedicated pathways) per 695 and local amendments.
ControllerListed controller, signage, and lock-open isolation where required; keep the path simple and serviceable.

CHART

Fire Pump Power Path

Component	Description
Service/Source	→ Fire Pump Controller (listed)
Controller	→ Fire Pump (motor)
Power Sources	Normal + Alternate Source (as required)
Protection	OCPD/Feeder arranged so pump keeps running

Keep OCPD/feeder choices aligned with reliability over convenience.

Labeling and source arrangement matter.

Follow 695 tap and OCPD specifics.

Chapter 6 — Special Equipment

Art. 600 — Electric Signs & Outline Lighting

Art. 620 — Elevators, Escalators, Platform Lifts

Art. 625 — Electric Vehicle Supply Equipment (EVSE)

Art. 630 — Electric Welders

Art. 640 — Audio Systems

Art. 645 — IT Equipment Rooms

Art. 680 — Pools, Fountains, Spas

Art. 690 — Photovoltaic Systems

Art. 691 — Large-Scale PV (Utility-Scale)

Art. 695 — Fire Pumps

Chapter 6 — Field Quick Hits

Signs

Elevators

EVSE

Pools

PV

Fire Pumps

Knowledge Check

Art. 600: A new storefront sign is being installed. What’s the correct branch-circuit approach?

Art. 620: Which is TRUE about elevator equipment circuits?

Art. 625: For EVSE, branch-circuit sizing typically uses:

Art. 630: Welder circuits are sized using:

Art. 640: One concern in audio racks is:

Art. 645: IT rooms using 645 rules typically provide:

Art. 680: What’s commonly required on pool pump motors?

Art. 680: The pool deck’s equipotential grid is primarily about:

Art. 690: PV output circuit ampacity is usually calculated at:

Art. 690: Rapid shutdown requirements primarily exist to:

Art. 691: Large-scale PV is different from 690 mainly because:

Art. 695: Fire pump power paths are arranged to prioritize:

Art. 600: Which is required for signs/outline lighting?

Art. 625: EVSE on a 40A nameplate should be on what size OCPD?

Art. 630: What commonly trips people up when sizing welder circuits?