2014 NEC CODE CHANGES CLASS PART III

CALCULATIONSTed “Smitty” Smith

8/15/2014E Light Electric Services, Inc

SOME NEW CHANGES TO BE AWARE OF……..

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Conductors of Different Systems 300.6(C)

• We can have conductors of different voltages in the same raceway, junction box, and enclosure under the following conditions– All of the circuits are 1000v or less– All of the conductors are rated for the highest

voltage in the box.

Corrosive Areas 330.6(A)

• Any field cut ferrous metal raceways, etc need to be suitably protected from corrosion in the environment– Field cuts have to have the corrosion protection

replaced• A new information note clarifies that a field

cut is any cut made anywhere other than at the factory

300.22(C) Other spaces used for Environmental Air (Plenums)

• Nonmetallic cable ties and other nonmetallic cable accessories used to secure and support cables shall be listed as having low smoke and heat release properties

300.38 Raceways in Wet Locations above Grade

• Where raceways are installed in wet locations above grade the interior of the raceway shall be considered a wet location.

Cables and Raceways on Rooftops Exposed to Direct Sunlight (T310.15(B)(3)(c)

• XHHN conductors are now exempted from this requirement

314.15 Boxes in Damp or Wet Locations

• We can now drill drainage holes in boxes listed for damp and wet locations as long as the hole is no larger than ¼ inch.

• We can also install listed drain fittings in larger holes as long as it is done according to the manufacturers instructions.

200.4(B) Neutral Marking

• If there is more than one neutral associated with different circuits in an enclosure the neutrals have to be identified or grouped so that they correspond with the ungrounded circuits for which they are associated. – This can be done by wire markers, cable ties, or

similar means in at least one location within the enclosure.

210.5(c)(1) Branch Circuit Identification

• They have further clarified the requirement to identify ungrounded conductors of systems with multiple voltages at all terminations, connection and splices by phase, line and system. – This clarifies the requirement in houses or

structures in single phase systems– This is easily enforceable and often violated

210.5(c)(2)

• They have added an entire new section about this for DC systems– More than 50 volts– 4 AWG or larger– Identified by Polarity– Ungrounded conductor– By marking tape, tagging– At all spices, terminations and connections

210.5(c)(2)• They have added an entire new section about this for DC systems

– More than 50 volts– 6 AWG and smaller– Positive Polarity

• Red outer finish• Red stripe continuously and durable• Imprinted plus signed or the work POSITIVE or POS repeated ate intervals of no

less than 24 inches– Negative Polarity

• Black outer finish• Black stripe continuously or durable• Imprinted minus sign, or word NEGATIVE OR NEG repeated at intervals no less

than 24 incues

Applies PV Systems

• This requirement has been added to 215 feeders as well

• And it is referenced in the PV article

225.56 Inspection and Tests

• Outside Branch Circuits and Feeders over 1000V

• Design including settings for protective devices, switching and control circuits have to be made available to the AHJ before energization And shall be performance tested when first installed on site

230.28 Service Masts

• New strength requirement or supported by guy wires

• Can not be connected to the mast between the weatherhead and the end of the conduit or coupling if the coupling is located above the last point of securement to the structure

• Weatherheads have to be identified for use as service-entrance equipment

230.30 Service Laterals

• Must be installed in only the following– RMC– IMC– NUCC– HDPE– PVC– RTRC– IGS cable– USE– MV or MC identified for direct burial

Conduit Fill Calculations

• Based on Tables 1, 4 and 5 in Chapter 9• Note 4 to Table 1• Can only use Annex C is all the conductors are

the same size and insulation• Start with Table 5 and get your volume used

then find the conduit on Table 4• Metric and Standard, do not convert

Load Calculations

• Two accepted methods– Standard– Optional• You can not mix the rules

• The purpose of a load calculation is to give us a safe value to base our service protection off that is less than the entire connected load. – Safe and cost effective

Two Methods

Standard• Divide the connected loads

into categories– Lighting and Receptacles– Cooking Equipment– Drying Equipment– Fasten in Place Appliances– Motors– Heating and AC

• Squeeze each category using the rules in Part II of 220

Optional • Separate all loads into two

categories– Heating and AC– And everything else

• Squeeze everything else all together

• Use lowest of the Heating and AC options

• Add the two together

Two Methods

Standard• More detailed• Can be legally used for all

services both residential and commercial

• Must be used as the default method for all test questions

Option• Less detailed• Usually results in a smaller

service size• Can be legally used for

services and is the most used

• Can ONLY be used on the test if the question specifically states : “Using the optional method….”

Steps for a Standard Load Calculation

Lighting Load• Includes receptacles for a

dwelling unit. Except for:– Kitchen counter top– Laundry

• Use Table based on square footage

• Add 220.52 A and B ( 4500 VA)

• Then Squeeze using 220.42

• Cooking Equipment 220.55• Electric Dryers 220.54• Fastened Place Appliances

220.53• 25% of largest motor 220.50• Heating and AC 220.51 and

220. 60

Practice Calculation

3600 Square feet of Habitable Space• 14 KW electric range @ 240V• 4.6 KW electric dryer @ 240 V• 1.1 KW dishwasher@ 120V• 1.4 KW trash compactor @ 120V• .9 KW garbage disposal @ 120V• 3.6 KW water heater @240 V• 2.1 KW AC at 240 V• (8) 2.1 KW Base Board space

heater, individually controlled @ 240V

Lets find the following:• Minimum sized service• Minimum sized service

entrance conductor if using THHN Aluminum

• Minimum sized Grounded conductor ( Neutral)

• Minimum sized main bonding jumping

• Minimum sized grounding electrode conductor