I want to put up a new fluorescent fixture in my basement. Right where I
would put a box for an outlet, there is a cable for an appropriate circuit.
The circuit was put in pretty sloppily, so I was able to get 4" of slack
right where the new box would go. Is that likely to be enough wire to add
an outlet? Seems adequate, but I don't want to cut it up and find I needed
If it turns out not to be enough, I would have to either put in a junction
box to add some wire, or pull out the last 10' of cable and replace it with
an 11' cable. That would be a lot of work since it all passes through floor
joists, but it would save a junction box. Is it worth it?
Given that the box you're adding will be 3-1/2 or 4 inches "wide" where
you insert it into the run, that 4 inches of slack should let all the
wires project about 4 inches into the box.
That should be plenty to let you pigtail on short lengths of wire
(including the ground conductor) and connect those to the new outlet's
But below Code, apparently... 300.14 (2005 NEC) requires 6" as the
minimum for conductor slack in a box. Do the inspectors tend to enforce
this rule, or is it squishy?
On the other hand, I read somewhere that inspectors disapprove of
"excessive" junction boxes. That seems strange to me, since extra boxes
would in some cases allow other parts of the Code to be met (like in
Toller's case) and provide more flexibility for repairs, future
Pull out that last eleven feet. You will need at least a foot of slack
to install a code compliant outlet box. I think that avoiding extra J
boxes is always a good thing but that is a personal preference.
"This alternating current stuff is just a fad. It is much too dangerous
Obviously there should be more material than the 4" I have (someone above
thought it was 6") to make it easier to work with, but as long as I have
nice secure connections, is there a safety reason for the 6"?
Sometimes code has a safety reason that I wouldn't have thought of, but
other times it is just convenience like the number of outlets in a room.
Cut the wire, insert both ends into the junction box, strip romex
jacket back inside the box, strip the colored conductor insulation back
as usual, twist the wires back together, add three (hot, neutral,
ground) 6" lengths of insulated wire (correctly color coded of course)
and twist one end of each wire to the corresponding splice, wire nut
each connection. You've just installed pigtails that conform to code.
Proceed with wiring the fixture as usual.
4" of slack will give you 2" of each end inside of a junction box. Pull out
the last 10' and run a new 11' or longer cable. The holes in the joists are
already drilled. It's not that difficult a job to pull out an old cable and
install a new one. You can cut the old one at different intervals to
facilitate its removal.
Sounds like I am going to be the only dissenting opinion.
I believe you will find that the slack mentioned will be painfully short
when it comes to working with the wires. I can not see it; 2 inches per
side is not really a lot to work with. I will concede that you might get
another couple of inches for a box depending on what you install. Now your
up to maybe 4 inches per side.
Some lighting fixtures are rated for a junction box, some are not. If you
were to install a 4 foot fixture that was rated as a junction box you would
not need to install one. Come in on one end and out the other.
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