HOW TO SELECT SIZE AND INSTALL ELECTRICAL METAL …

1 ANOTHERG & G ELECTRIC AND PLUMBING DISTRIBUTORS, SHEETCOPYRIGHT 198913 These How-To-Do-It sheets have been reviewed in June 2007 by a professional Engineer. If you find a problem, please notifyG & G Electric & Plumbing at 1900 NE 78th Street, Ste. 101, Vancouver, Washington 98665 HOW TO SELECT SIZE AND INSTALL ELECTRICAL METAL is used in both concealed and exposedwork in commercial and residential applicationswhere, during or after installation, exposedconductors would be subject to physical harm orwould be rendered inaccessible inside of walls orceilings. Individual wires that are not containedwithin a jacketed cable must also be run inconduit. Some wiring jobs that require the useof conduit cannot be done with butnecessitate the use of rigid galvanized steelconduit.

2 Where an explosion-proof system isrequired or where the conduit is subject to apermanent moisture condition, rigid conduitmust be used. Around the home, isusually only used for surface circuit extensionssuch as patio lighting or for surface-mountedbasement and work shop wiring. It is also usedto provide physical protection for cables wherethey pass through an open area. An example ofthis use would be an underground cable fromthe exterior wall until it gets to the correct burialdepth in the ground and, perhaps, to evenbeyond the flower bed cut ends of should be reamed toremove any burrs from the inside. shouldbe supported with approved straps at leastevery 10 feet and within 3 feet of each point oftermination.

3 Fittings for coupling orconnecting to boxes should be made up tightand where installed in wet locations or in con-crete must be the compression type. Short turn"elbows and offset connectors are available toaid in making neat entry into in any conduit run (between two pointswhere permanent access is assured) can totalno more than 360 degrees, the equivalent offour 1/4 bends. This is the maximum and is verydifficult to pull wires through so it is best to holdthe number of bends you use to a must be made so as not to injure thetubing or effectively reduce its internaldiameter. benders are the practical toolsfor making bends BUT DO NOT use them tobend rigid galvanized conduit .

4 See other side ofsheet for instruction for making some popularbends. ALSO SEE ARTICLE 358 OF NFPANATIONAL ELECTRICAL CODE for additionalinformation on uses and number of wires that can be run inconduit are governed by the tables in chapter 9of the NFPA National ELECTRICAL Code (NEC). Thechart below lists the more popular wire typesand sizes and is based on Article and theChapter 9 tables of the WIRE CAPACITY CHARTT rade Size ConduitTYPE OF WIRECONDUCTORSIZE AWG1/23/411-1/41-1/222-1/23#14122235#129 162645#10510162838T H H No rT H W N#8369162236#61348111832#411368132436#21 1246101726#111134712181/01123610162/0111 359133/011124711T H W4/0111369 ANOTHERG & G ELECTRIC AND PLUMBING DISTRIBUTORS, SHEETCOPYRIGHT 198913 These How-To-Do-It sheets have been reviewed in June 2007 by a professional Engineer.

5 If you find a problem, please notifyG & G Electric & Plumbing at 1900 NE 78th Street, Ste. 101, Vancouver, Washington 98665 HOW TO MAKE POPULAR conduit BENDSMost conduit benders are very similar in appearance and dimension, but may not be exactly alike. Thedirections below were designed to be used with a typical hand bender. You may need to modify the dimensionsgiven to get correct results. For sizes over 1 in diameter, we recommend using a factory-made bend andcoupling it in where needed.