... which is a Code violation and potential fire hazard, unless the receptacles
are rated for use
with AWG 10 conductors (or unless you used AWG 12 pigtails between that and the
The issue is that unless the receptacle was designed for AWG 10 conductors, it's
to properly secure one that large under the terminal screw, and it may work
loose, leading to
arcing and fire.
On Friday, July 22, 2016 at 5:16:25 AM UTC-4, Rusty Boldt wrote:
I ran #12 when I installed a garbage disposal and would have had a heck of
a time getting #10 pulled through those bends. Thicker sizes are a pain fo
r an amateur to handle. Of course pros do it every day.
Here's what I'm wondering. You're in your shed working on a project late a
t night. You're surrounded by disassembled pieces, some of which you'll ne
ver figure out where to put if you disturb your layout, some breakable, som
e sharp. You power up your saw or other tool and trip the breaker.
Do the lights die too? Are you now in the dark unable to move without trip
ping over stuff? Or does just the outlet breaker trip?
Solid or stranded? I almost always pull stranded for #10 and larger...
'Pends on whether you thought ahead when wiring or no... :) Ideally,
there even ought to be two light circuits, too, altho for just a small
shed it's overkill. Having split circuits in a multi-story house for
example means you can at least find your way to the panel in the
basement instead of the whole place being dark as a parallel idea...
On 7/22/2016 2:10 PM, email@example.com wrote:
I have the packaging for two 20 amp commercial spec receptacles, one Leviton and one Pass and Seymour.
Neither package specs the wire size or the max number of wires attached to the device.
I'd really appreciate a manufacturers link to info listing max number of wires and max wire size.
Years ago I tried to find this info and gave up. Unless the device says otherwise, if there is an open screw head I'll use it.
The above link to this device does list the wire size(s) and type (back
terminal Cu only) but like yours I see no mention of limiting the number
or which connections can be used simultaneously.
I searched for the UL reference numbers to see if they would say
something but had no luck on the score, either.
Certainly on duplex outlets without the rear connections it's very
common to wire outlets in series using the two sets of side screws and
GFCI duplex outlets are constructed specifically with a "line" and
"load" side for the purpose. Simply adding the two additional rear
contacts doesn't seem to me to make sense to prevent their use if
convenient and as you say, I've never seen anything saying "Don't do that!".
So, I think the "one terminal, one wire" rule is Code-compliant but I
don't know how to prove it w/o a lot more effort than I've time or
inclination to invest.
From the 2014 U/L white book
Single and duplex receptacles rated 15 and 20 A that are provided with
more than one set of terminals for the connection of line and neutral
have not been investigated to feed branch-circuit conductors connected
to other outlets on a multi-outlet branch circuit, as follows:
Side-wire (binding screw) terminal with its associated back-wire
(.screw-actuated clamp type) terminal .
Multiple conductors under a single binding screw
Multiple conductors in a single back-wire hole
If these are NOT investigated, the listing does not apply so it is an
unlisted use and a NEC violation.
OTOH you can use a push in and the screw.
I think the issue is that a terminal screw can only have that use. It
can't be used for another purpose, like tensioning the back plate. You
also run into problems that if the plate is all the way open to insert
conductors, the screw may not be long enough to get a wire under it.
Using the 2 sets of terminals as a feed through has been evaluated
and is legal.
On 07/22/2016 3:00 PM, firstname.lastname@example.org wrote:
OK, that's useful...
Of the three, only the first isn't clearly a silly thing; I'd think the
first would/should be made more FAR more prominent than it is by the
manufacturers although having more than the four connections for a
single daisy-chain isn't all that common, one could certainly not have
too much trouble in finding places where it would be useful.
I'm surprised it isn't published much more obviously than is -- although
I guess on reflection that just says UL doesn't do the investigation
routinely; doesn't say about any particular device so there's always the
chance (however remote) they had the extra work done...not that one
would expect it.
On 07/22/2016 3:39 PM, email@example.com wrote:
Only would need a third cable to have the six wires to exceed the two
sets of screws and so use two back-entry locations...w/ a deep box
that's easily within fill limits...likely even be ok on standard, tho
didn't double-check; certainly common number w/ 3- and 4- way switches...
Was going to add...I'm still amazed there's nothing in manufacturer's
routine lit (or even any instruction sheets that I was able to find)
that says word one about it if it isn't ok (which, given the UL words
one at least has to wonder about as it would be extra cost to the
manufacturer to get the added cert which you wouldn't think would be
Even using #14, 6 conductors, plus one for the grounds and 2 for the
device makes 18cu/in That is a big single gang box (3x2x3.5)and if you
use #12 you are talking about 20.5 cu/in and that is bigger than any
standard single gang box. The only one I can think of is the 3.5"
masonry box. at 21 cu/in.
A standard 2.5" depth box is not even big enough for 2 #12 cables
unless you have the bump out on the side.
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