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I am wanting to add a permanent attic ladder to create storage space in a big attic. There is already exposed wiring in a few places in the attic. If I add a permanent ladder, does that then mean that according to code that all attic wires now need to be protected? Some of the cable would be covered by 3/4" plywood for flooring, but other cable is hanging above in the rafter braces. If I add this ladder, what are some different options to protect this hanging cable so it meets code? Or is that really necessary if it's not in the main part of the attic for storage that will have the plywood flooring?

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I have never had an AHJ confront me about exposed romex in an attic with or without a permanent ladder. One quick note though, if you are laying down plywood Make sure there are no electrical cables laying across the joist where they may be pinched and shorted. Notch the joist and use nail plates or reroute the cables.

Good luck

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    Never notch joists. That's the wrong way to do it and substantially reduces their span strength. It's very different from notching studs. – isherwood Jun 24 '18 at 13:51
  • @isherwood - How would you suggest he do it? – Retired Master Electrician Jun 25 '18 at 12:43
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    Depends on the joists. If we're talking standard 2x4 truss chords, 5/8" or 3/4" holes in the middle third of the member is appropriate. Otherwise, re-route outside the floored area. – isherwood Jun 25 '18 at 13:12
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    Instead of notching or drilling holes (means re-running the wire completely), lay some 2x2s or something in the opposite direction of the joists before laying the plywood. Then you don't need to touch the wires. You could even use taller lumber and add extra ceiling insulation if you wanted. – jmpreiks Jun 28 '18 at 21:07
  • @jmpreiks That's the complete solution, but it's more work and cost, is heavy, and cuts down on headroom. May not be the best approach, based on the situation. – Daniel Griscom Oct 4 '18 at 12:29
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If you install a permanent ladder, the attic is now considered "accessible" and per the code section below the cables have to be protected. However, note that you're only required to protect the cables running across the faces of rafters or studding, not cables running between the rafters or studding. If, as you say, the cables are up between the rafters, on the bracing, they are not affected by this rule.

If you need to route cable through the joists, you can notch or bore holes in the joist. The illustration below shows that you can notch the OUTER thirds of the joist a maximum of one sixth the width deep and one third the width long. Wires in notches will require a nail plate for protection. Bored holes can be up to 1/3 the width of the joist, but must be 2" from the edge. With 2x6's, the actual width is 5-1/2" so there is room to spare for holes in the 3/4" to 1" range centered or nearly centered through the joist.

WWPA - Placement of Cuts In Floor Joists

NEC 320.23(A)

Where Run Across the Top of Floor Joists. Where run across the top of floor joists, or within 2.1 m (7 ft) of floor or floor joists across the face of rafters or studding, in attics and roof spaces that are accessible, the cable shall be protected by substantial guard strips that are at least as high as the cable. Where this space is not accessible by permanent stairs or ladders, protection shall only be required within 1.8 m (6 ft) of the nearest edge of the scuttle hole or attic entrance.

Note - 320.23 is a rule pertaining to AC cable, not NM such as Romex brand; but the rule for NM, 334.23, references 320.23.

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