2014 NEC C ODE C HANGES C LASS P ART III C ALCULATIONS Ted “Smitty” Smith 8/15/2014 E Light Electric Services, Inc

S OME N EW C HANGES TO B E A WARE OF ……..

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

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

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

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

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

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 A and B ( 4500 VA) Then Squeeze using Cooking Equipment Electric Dryers Fastened Place Appliances % of largest motor Heating and AC and

Practice Calculation 3600 Square feet of Habitable Space 14 KW electric 240V 4.6 KW electric 240 V 1.1 KW 120V 1.4 KW trash 120V.9 KW garbage 120V 3.6 KW water V 2.1 KW AC at 240 V (8) 2.1 KW Base Board space heater, individually 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