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+---
+id:
+aliases:
+  - nec-310
+tags:
+  - authorship/other
+  - destiny/uncertain
+  - status/incomplete
+  - topic/electrical
+  - type/media
+title:
+---
+# Article 300: General Requirements for Wiring Methods and Materials
+
+## Part I. General Requirements
+
+### 300.1 Scope.
+
+#### 300.1(A) All Wiring Installations.
+
+This article covers general requirements for wiring methods and materials for all wiring installations unless modified by other articles in Chapter 3.
+
+#### 300.1(B) Integral Parts of Equipment.
+
+The provisions of this article are not intended to apply to the conductors that form an integral part of equipment, such as motors, controllers, motor control centers, or factory-assembled control equipment or listed utilization equipment.
+
+#### 300.1(C) Metric Designators and Trade Sizes.
+
+Metric designators and trade sizes for conduit, tubing, and associated fittings and accessories shall be as designated in Table 300.1(C).
+
+#### Table 300.1(C) Metric Designators and Trade Sizes
+
+| Metric Designator | Trade Size |
+| -----------------:| ----------:|
+|                12 |        3/8 |
+|                16 |        1/2 |
+|                21 |        3/4 |
+|                27 |          1 |
+|                35 |      1-1/4 |
+|                41 |      1-1/2 |
+|                53 |          2 |
+|                63 |      2-1/2 |
+|                78 |          3 |
+|                91 |      3-1/2 |
+|               103 |          4 |
+|               129 |          5 |
+|               155 |          6 |
+
+<!-- TODO: TEXT OMITTED -->
+
+### 300.19 Supporting Conductors in Vertical Raceways.
+
+#### 300.19(A) Spacing Intervals -- Maximum.
+
+Conductors in vertical raceways shall be supported
+if the vertical rise exceeds the values in Table 300.19(A).
+At least one support method shall be provided for each conductor
+at the top of the vertical raceway or as close to the top as practical.
+Intermediate supports shall be provided
+as necessary to limit supported conductor lengths
+to not greater than those values specified in Table 300.19(A).
+
+#### Table 300.19(A) Spacings for Conductor Supports
+
+| Conductor Size                   | Aluminum or Copper-Clad Aluminum | Copper |
+| -------------------------------- | --------------------------------:| ------:|
+| 18 AWG through 8 AWG             |                            100ft |  100ft |
+| 6 AWG through 1/0 AWG            |                            200ft |  100ft |
+| 2/0 AWG through 4/0 AWG          |                            180ft |   80ft |
+| Over 4/0 AWG through 350 kcmil   |                            135ft |   60ft |
+| Over 350 kcmil through 500 kcmil |                            120ft |   50ft |
+| Over 500 kcmil through 750 kcmil |                             95ft |   40ft |
+| Over 750 kcmil                   |                             85ft |   35ft |
+
+#### 300.19(B) Fire-Rated Cables and Conductors.
+
+Support methods and spacing intervals for fire-rated cables and conductors
+shall comply with any restrictions provided in the listing
+of the electrical circuit protective system used
+and in no case shall exceed the values in Table 300.19(A).
+
+#### 300.19(C) Support Methods.
+
+One of the following methods of support shall be used:
+
+1. Clamping devices constructed of or employing insulating wedges
+  inserted in the ends of the raceways.
+  Where clamping of insulation does not adequately support the cable,
+  the conductor also shall be clamped.
+
+2. Inserting boxes at the required intervals
+  in which insulating supports are installed and secured
+  in an approved manner to withstand the weight of the conductors attached thereto,
+  the boxes being provided with covers.
+
+3. In junction boxes, deflecting the cables not less than 90 degrees
+  and carrying them horizontally to a distance not less than twice the diameter of the cable,
+  the cables being carried on two or more insulating supports
+  and additionally secured thereto by tie wires, if desired.
+  Where this method is used, cables shall be supported at intervals
+  not greater than 20 percent of the support spacing in Table 300.19(A).
+
+4. Other approved means.
+
+<!-- TODO: TEXT OMITTED -->