i have no access to a nec publication, so i thought i'd ask around until i can get a hold of one.
i purchased an old house (30's) and some of the wiring are old (still on insulators). i don't like digging around for cable under weather insulation. can i hang (from the roof rafters) or suspend it from the joist?
the house is on pier and beam. i thought "floating" it (vs stapling) will keep the wires from getting stretched as the house/foundation moves.
tia
All junction boxes should be attached to the structure. Any box for "hanging" fixtures needs to be rated for that purpose. Any hanging fixture usually comes with a chain or support device that is attached to the structure either directly or through the rated support box.
If the home is circa 1930's it is time to think about a complete electrical upgrade, service and all wiring. Way back then there were no ground conductors (usually) and the newer electronic devices like to be grounded.
Not sure what you mean by "floating" but code requires that cables be stapled properly. If by "floating" you mean "sagging", then No.
Generally code prohibits running cables unprotected on the bottom of joists and rafters. If the space is one that will never be finished, like a crawlspace, it should be ok to nail "running boards" to the joists and then staple the cables along the boards. In attics you may be restricted to areas of low height, like less than four feet or so. I believe it's never ok to run cables along the tops of ceiling joists in an attic.
Otherwise the "right" way is to drill holes in the joists and pull cables through them. The holes need to be a certain distance from the edges so if someone ever attaches a ceiling or floor (or a new roof on the rafters) the nails won't reach the cables. If you've got knob and tube, someone's already done a lot of drilling (maybe with a brace and bit, something to think about as your cordless drill purrs along) and usually the holes are the right size and in the right place. Of course you've got to remove the wire and the tubes first.
See if your big-box stores have a book that shows the code simplified. Around here HD carries one called "Electrical Code Simplified" by P.S. Knight; specific versions are published for each province. I would assume something similar is available in the States. You'd want one as specific to your jurisdiction as possible.
Chip C Toronto
this is meant (attempt anyway) to respond to those that replied.
i had thought about the running board. but am not sure if i can suspend it (yes, with support/straps vs stapling). basically all i was thinking was to have easy access to the wires and not have them buried under attic insulation.
yes, a few of the circuits were new runs ("modern" cables). but, some that go to light switches etc are still on knobs and tubes. so, they are definitely going to go.
i'll do a running board instead, and clear out the insulation along side it to provide access.
thx richard
if it is more, you must use a running board.
this should answer it.
also, if the rafters are engineered wood, do not drill trhough them (they should not be in house from 30's)
martin
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