[ASKNACHI]This question was posted on AskNACHI.org by Charles (from Rome, PA). [/ASKNACHI]I was told that I must fasten NM cable every 4-1/2 feet in the attic above a garage because it has a permanent stairway for access to thisspace. Is the retractable stairway considered permanent stairs?
I don’t have an answer for you, but wanted to welcome you to Ask Nachi and let you know that there are lots of knowledgeable inspectors here, and I’m sure someone will be along soon with your answer.
They almost got it right.
NM is required to be secured at intervals not to exceed 54", regardless of the access.
If there is a permanent ladder or stairway (a retractable counts as permanent), you need nothing additional.
Without a permanent access, the cable must be shielded or otherwise protected within 6 feet of the access.
Once again I find myself in total agreement with Mr. Pope.
With the understanding that I am not a Code Official (from Pennsylvania) I will submit my interpretation.
NEC 334.30 requires one to support NM cable at intervals not exceeding 4-1/2 feet everywhere it is installed, except where it is within a protective raceway or where it is fished. (i.e. inside a wall or a chase).
NEC 334.23 In Accessible Attics further explains and refers you to NEC 320.23, "where substantial guard strips are required in accessible attic spaces. If the space isn’t accessible by permanent stairs or ladders, protection is only required within 6 ft of the scuttle hole or attic entrance.
Retractable stairways are considered a permanent stairway solely based on there generally accepted construction of being permanently located.