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What is the typical code for wiring in attics? I understand these vary but what's best practice?

Can you just have electrical wires exposed with all the junctions, in junction boxes, provided all the exposed wiring is anchored to the wood studs? What about insulation that comes in contact with the wiring? Or does the wiring have to be an aluminum armor?

  • What type of cable are you planning to run? The codes can be slightly different depending on the type of cable. – Tester101 Feb 18 '13 at 12:07
  • Is the attic accessible via a ladder, or a staircase? Can you stand up in most of the attic? Are the framing members exposed, or covered (by drywall, plaster, etc.)? – Tester101 Feb 18 '13 at 19:21
  • I think some folks are thinking you mean knob and tube wiring since you said exposed. I took it to be the cable (romex) was going to be exposed. But we need to know the type of wire and the type of access to the attic (scuttle hole, stairs) to provide a complete answer. – Ed Beal Jul 19 '17 at 19:08
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"Can you just have electrical wires exposed with all the junctions, in junction boxes, provided all the exposed wiring is anchored to the wood studs? What about insulation that comes in contact with the wiring? Or does the wiring have to be an aluminum armor?"

Wiring should be stapled to the wood studs and have splices in accessible junction boxes. Check local electrical codes for specific requirements.

There are no issues with modern wiring touching insulation. It touches insulation all the time in your walls.

I guess I need to cover more bases: Don't use knob and tube. ever.

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    NEC 2008 394.12 Uses Not Permitted. Concealed knob-and-tube wiring shall not be used in the following: (5) Hollow spaces of walls, ceilings, and attics where such spaces are insulated by loose, rolled, or foamed-inplace insulating material that envelops the conductors. Also, it may not be as simple as stapling the wiring to the structural members. There are codes for how far apart staples have to be, what the wires can be stapled to, and where on the structural members the wires can be stapled. Not to mention, codes that specify how wires can pass through structural members. – Tester101 Feb 18 '13 at 12:40
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    @Tester101 So it is an incomplete answer, but how does that make it a bad answer? Nothing he says is incorrect. Nothing in the question suggests either that knob and tube wiring is present. – maple_shaft Feb 18 '13 at 13:40
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    When it comes to electricity, an incomplete answer is a bad answer. – Tester101 Feb 18 '13 at 14:17
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    Dear lord... If that is the case I could assume every answer on this site is incomplete, because I could think of some possible case it doesn't cover. For example don't slice chunks off the insulation, don't fold the wire back on itself and make kinks, don't just shove wires in the junction box, use connectors, make sure you ground the boxes, etc., ..., ... – ryanwinchester Feb 18 '13 at 18:30
  • @decker I'm trying to illustrate that this is much more complex than simply stapling wires to wood, and that a three sentence answer is an oversimplification of what's actually involved. – Tester101 Feb 18 '13 at 19:00

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