- #PLASTER RINGS TO INCREASE NUMBER OF CONDUCTORS FULL#
- #PLASTER RINGS TO INCREASE NUMBER OF CONDUCTORS CODE#
- #PLASTER RINGS TO INCREASE NUMBER OF CONDUCTORS FREE#
Besides having the cubic-inch capacity marked on (or in) the box, ring, cover, etc., the box could be made from boxes the dimensions of which are listed in Table 370-16(a). Additional cubic-inch capacity can be gained by using plaster (mud) rings, domed covers, extension rings, or similar devices. The volume of a wiring enclosure (box) is the total volume of the assembled sections. A 3-inch by 2-inch device box, 2.5 inches deep, has a volume of 12.5 cubic inches. Instead, the calculation is based on the box's actual (inside) volume. Note the volume is not calculated by using the box's outside dimension. Fewer conductors are allowed in boxes that contain fittings or devices.Ī 4-inch square box (also known as a 1900 box, a 4-S box, or a 4-square box) with a depth of 1.5 inches, has a volume of 21 cubic inches, as listed in Table 370-16(a). The maximum number of conductors is based on the same size conductors in a box containing no fittings or devices, such as fixture studs, cable clamps, hickeys, switches, or receptacles. This table also provides the minimum cubic inch capacity, as well as the maximum number of conductors (for sizes No. Table 370-16(a) lists the most commonly used metal boxes along with the maximum number of conductors permitted in each. These boxes are calculated by using the number of conductors and their respective sizes. Use Section 370-16 to determine the size box required for No. Unlike junction boxes and conduit bodies, terminal housings supplied with motors are not required to comply with Article 370. Conduit bodies, also referred to as condulets, occur in a variety of types, including: LB, LL, LR, C, etc. Conduit body requirements are located in Section 370-16(c). In no case shall the volume of the box, as calculated in (a), be less than the fill calculation as determined in (b). Two sections refer to these calculations: 370-16(a) Box Volume Calculations, and 370-16(b) Box Fill Calculations. (The phrase "free space" should not be confused with "free conductor" located in Section 300-14.)
#PLASTER RINGS TO INCREASE NUMBER OF CONDUCTORS FREE#
ģ70-16 Number of Conductors in Outlet, Device, and Junction Boxes, and Conduit Bodiesīoxes and conduit bodies must be of sufficient size to provide free space for all enclosed conductors.
Hazardous (classified) location installations must comply with Articles 500 through 517. Installations in any of the following categories are wet locations: underground, within concrete slabs, in masonry (directly contacting the earth), areas subject to saturation (water and other liquids), and locations unprotected from weather. Dry locations are not normally subject to moisture, except on a temporary basis, such as a building under construction.īoxes, conduit bodies, and fittings installed in wet locations must be listed for that specific use.
Partially protected external locations under canopies, marquees, roofed (open) porches, and similar sites are considered damp locations as are some interior locations such as certain basements, barns, and cold-storage warehouses. Damp locations, as defined in Article 100, are locations subject to moderate degrees of moisture. This month's In Focus discusses Installation (Part B).ģ70-15 Damp, Wet, or Hazardous (Classified) Locationsīoxes, conduit bodies, and fittings in damp or wet locations must be placed or equipped so as to prevent the entrance of, or internal accumulation of, moisture. Pull and Junction Boxes for Use on Systems Over 600 Volts, Nominal. Manholes and Other Electric Enclosures Intended for Personnel Entry (new to the 1999 edition), and E. It also covers manholes (including other electric enclosures intended for personnel entry). It covers the installation and use of all boxes (and conduit bodies) used as outlet, junction, or pull boxes, depending on their use.
#PLASTER RINGS TO INCREASE NUMBER OF CONDUCTORS CODE#
Article 370 contains detailed requirements for box fill and junction box sizing.Īrticle 370 of the National Electrical Code (NEC) covers a variety of provisions pertaining to boxes (outlet, device, pull junction), conduit bodies, and fittings. Of course, not one of these methods is correct. An optional creative method is to back out the junction box screws, insert a blank plate, then tighten the screws, thereby compressing the conductors. Such methods include, but are not limited to: carefully wrapping the conductors around the inside of the box so that no air space remains mashing the conductors down with the thumb, the heel of the hand or even by applying force with the handle of a hammer.
Some creative methods have been devised to overpack the conductors into a junction box so that the cover can still be installed.
#PLASTER RINGS TO INCREASE NUMBER OF CONDUCTORS FULL#
Unfortunately, all too often, electricians remove junction box covers only to find the box crammed full of conductors. Contrary to popular electrical opinion, designated rules limit the number of conductors allowed within outlet, device, and junction boxes.
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