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PRACTICAL ELCTRICITY. National Electric Code. Not For Publication. The Code. What it is Purpose Terms & Definitions Qualified Wire & Conduit Selection Physical Application Grounding, GFCI AFCI Disconnects Load Panels. The Code. Three year cycle 2002, 2005, 2008 Interpretations

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Practical elctricity

PRACTICAL ELCTRICITY

National Electric Code

Not For Publication


The code
The Code

  • What it is

  • Purpose

  • Terms & Definitions

  • Qualified

  • Wire & Conduit Selection

  • Physical Application

  • Grounding, GFCI AFCI

  • Disconnects Load Panels


The code1
The Code

  • Three year cycle

    • 2002, 2005, 2008

  • Interpretations

  • Usually Adopted by city as is

  • Purpose = Practical safeguarding of persons and property from hazards arising from the use of electricity

  • If comply = free from Haz, but not necessarily efficient, convenient, or adequate for good service or future expansion of elec use.


Grounding 250
Grounding 250

  • Metal Water Pipe 250.52A1

  • Bond around Water Meters

  • Water Pipe Cannot Be only Electrode 250.53D2

  • Cu Rods Min size 1/2” x 8’ L&L. Vertical, below grade

  • 2 rods

  • Metal Well Casings

  • Metal building frame, exterior siding

  • Do not Use Gas Pipe as electrode


Grounding electrode
Grounding Electrode

  • Must connect to Neutral at or before service

  • Sized per service size, 100, 200, etc

  • No splices

  • Connection to water pipe must be made within 5 ft of entrance to bldg

  • Buried Clamps L&L

  • One conductor per clamp

  • Connections accessible except buried


Bonding
Bonding

  • Bonding ensures electrical continuity to prevent differences of potential between conductive components.

  • Use parts made for the task

  • Lightening Rods are to be bonded to electrical system

  • Bond all piping hot cold and gas


Equipment grounding conductor
Equipment Grounding Conductor

  • Sized per OCPD

    • 15A = 14 awg

    • 20A = 12 awg

  • Can be bare, green, green with yellow stripe

  • Can be > #6 OK to strip bare or use green tape

  • Can be the rigid pipe, or emt or imt


Ground fault circuit interrupters
Ground Fault Circuit Interrupters

  • Detect the escape of electrical current outside the intended path.

  • Breakers

  • Outlets

  • Blind


Gfci where
GFCI, Where?

  • All Kitchen counters

  • All bathrooms

  • Within 6 ft of sink

  • HVAC Recept

  • Garages

  • Unfinished basements

  • Within 20 ft of a pool

  • Pool pumps, spa, hot tubs

  • Front and rear of dwelling


Arc fault circuit interrupters
Arc Fault Circuit Interrupters

  • Arc Fault breakers are intended to provide protection by opening the circuit if an arcing fault is detected. Often have GFI protection built in


Service drops entrance cables
Service Drops & Entrance Cables

  • Height 12 ft driveway

  • 22.5 ft above a pool

  • No trees for support

  • Use wire rated for such use

  • Use warning ribbon 12 above underground feed lateral

  • 3 feet around window openings

    SE Conductors

  • Identify the Neutral with white tape

  • Protect them against damage

  • Utilize a drip loop

  • Clamp and strap as required


Service installation do don ts
Service InstallationDo/Don’ts

  • Meters too close to gas pipe 3 Ft from feed side, 10” from house side

  • Wrong height

  • Not accessible

  • Length of wires at weather head too short

  • Roof heights not correct

  • Weather head should be 1 foot higher than point of attachment

  • Point of attachment too far from weather head

  • Service cable has to be on the exterior

  • Working space at panels insufficient



Service panel
Service Panel

  • Neutral Conductor is bonded to service enclosure.

  • Once Neutral leave service they must always be isolated from equipment and enclosures

  • Front working clearance 30 w and 36 deep

  • Wet, must be rated for area?

  • All open KO filled

  • NO panels in bathroom or closet

  • Must be accessible

  • All breakers correct brand

  • One wire per screw, ONLY

  • Clearly marked circuit ID

  • Approved handle ties breakers

  • Multi-wire feeds must have handles tied

  • Use antioxidant on Al wire


Service feeder calculations
Service & Feeder Calculations

  • Guidelines in the code help anticipate the size and number of circuits needed to supply the loads in a home. Code states service conductors, feeders, branch circuits must be sufficient to serve the connected loads.

  • Since not everything will be ON at the same time, code allows to use demand factors.


Multi wire circuits
Multi-wire Circuits

  • Unbalanced Unequal loads requires the neutral to carry the current


Branch circuits
Branch Circuits

  • They are intended to supply the loads.

  • Required branch circuits are minimal, more are required for convenience and safety.

  • Smallest branch circuit is #14 with 15A breaker

  • Rule of thumb, 1 GP cir per 500 sq feet

  • Wall > 2 ft req recept

  • Hallways greater than 10 req recept


Kitchen
Kitchen

  • Min 2 20A mp GFI Circuits

  • Serve no other areas or items

  • DW and Disposer separate cir

  • Island / Peninsulas require outlets

  • If > 6 overhang outlet can be 12” below


Bathrooms
Bathrooms

  • Within 3 ft of basin

  • Dedicated 20 A

  • Pumps equipment accessible tubs


Laundry
Laundry

  • 1, 20A w/ in 6ft of appliance GFCI

  • Dryer circuit 30 Amp/250V


Other
Other

  • Outdoors, front and back accessible <6.5 ft

  • Luminaries required at grade level doors.

  • ADA ?



Cable systems
Cable Systems

  • NM, NMB

  • BX

  • UF

  • SE SEU


NM

  • OK in dry locations

  • Protect from damage

  • Strain reliefs

  • Use 60 deg column (90 deg wire)

  • Derate when bundled in a hole

  • Secure w/in 12” box & 4.5’ intervals

  • Don’t kill the staples


BX

  • Dry Locations only

  • Secure w/in 12 of box & 4.5’

  • Use insulated bushings, red hats

  • Don’t bring bonding wire into box

  • Secure each joist if underside


UF

  • Inside use same rules as NM

  • Bury per table

  • Protect where emerging from earth 18”

  • Uv resistant where necessary


SE

  • Intended for service entrance

  • Inside same rules as NM

  • SEU same rules as UF

  • Gradual bends (5x dia)

  • Weatherproof connections


Voltage drop
Voltage Drop

  • Consider long runs, target between 3-5%

  • Use larger wire


Protecting cables
Protecting Cables

  • Nailer Plates L&L

  • Rafters, running boards

  • Standoff Clamps


Raceways conduits tubing conduit fill
RacewaysConduits, Tubing, Conduit Fill

  • EMT

  • RMC

  • LFMC

  • ENT Smurf

  • RNC PVC


Installation requirements
Installation Requirements

  • 360

  • Clean and Ream

  • Condulets Boxes remain accessible

  • 40% Fill if >2 conductors


EMT

  • Do Not Bury

  • Use Raintight where required

  • Secure at 10’ intervals

  • Supports condulets not boxes


Rigid conduit
Rigid Conduit

  • OK to bury

  • Clean and Ream

  • Support at 10’ intervals


Liquid tight flex conduit
Liquid Tight Flex Conduit

  • OK for WET

  • 6 Ft Rule


Electrical nonmetallic tubing rigid non metallic conduit pvc

ENT

Do not bury

Temp max 122F

Secure 3 Ft

PVC

OK Bury, depth?

Temp max 122F

Support often

Expansion joints

Electrical Nonmetallic TubingRigid Non Metallic Conduit PVC



Condulets
Condulets

  • Various configurations and sizes

  • No splices !!


Boxes
Boxes

  • Boxes are necessary to safely enclose and protect wiring splices and support devices and light fixtures


Boxes generalities
Boxes, Generalities

  • Metal must be grounded

  • Must be accessible

  • 1/4 “ setback max

  • No gaps by wall board

  • Must be supported/mounted

  • Outside require In use Covers


Box fill
Box Fill

  • Size of box MUST be OK to provide enough free space for conductors


Calculating box fill
Calculating Box Fill

  • Count number and size

  • Internal clamps count as 1

  • Devices count as 2

  • EGC counts as 1

  • Pigtails Do No Count



Other box requirements
Other Box Requirements

  • In Use Covers

  • Cutouts and depth


Appliances
Appliances

  • Anything other than lighting

  • Cord and plug OK for disconnect

  • Disconnect means are usually in sight


Kitchen1
Kitchen

  • Disposer

  • DW


HVAC

  • Disconnect in Sight of Outside Unit

  • Requires 20A GFI Rec


Furnace
Furnace

  • Disconnect In Sight

  • Some manuf require fuses


Water heater
Water Heater

  • Disconnect in sight

  • Bond pipes, all 3


Paddle fans
Paddle Fans

  • Use L&L box

  • >70 requires separate support

  • Normal up to 35

  • 7 Ft Height


Lighting
Lighting

  • Point to remember is bulbs create heat, and must be kept from combustible materials

  • There are required lighting locations

  • Clearances for recessed

  • Closets are also special


Required lighting
Required Lighting

  • Wall switch control in all habitable locations bedrooms, kitchens and bathrooms

  • May be switched outlets except in bathroom and kitchen

  • Garage, halls, and stairs require switched lighting


Recessed lighting
Recessed Lighting

  • Non IC away from insulation 3”

  • Non IC away from combustibles ½”

  • IC OK contact insulation and combustibles

  • Don’t over wattage, read trim and rough labels



Switching requirements
Switching Requirements

  • All Switches must be grounded

  • Cover must be large enough to cover

  • Re-identify white wire if used as an ungrounded



Pools
Pools

  • No Overhead Wires or 22.5 clearance

  • No EMT

  • Min EGC #12 and no splices

  • GFCI on Pump

  • GFCI on all lighting

  • GCFI on everything



Arrays and components
Arrays and Components

  • Remember any building codes

  • L&L Equipment

  • Correct OCPD

  • DC Ground fault protector

  • All current rated continuous,



Generators
Generators

  • Must be suitable for intended application

  • All conductors sized 125% of namplate

  • Transfer Switches

    • Sign req at service advising of generator

    • If Neutral is switched, cannot be bonded to generator case


Other stuff
Other Stuff

  • Knob and Tube



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