Electical Code Test

I know…I know…“we are not code inspectors”.

This is for anyone who wants to play along. Anyone see anything wrong?

I used to leave my gum under the desk.

That’s a very nice staple you got there.

If it’s 1.25" from the edge of the stud then it looks fine to me.

Do you see the 2"-2-1/2" staple?

Yup, but what does that have to do with this being an electrical code test? The requirement is that the hole edge be 1.25" from the wood edge. Looks like it’s in the center of the wood which makes it compliant, unless I’m missing something?

I understand that but it was the only issue I saw.:wink:

Good catch that makes me wonder if that is what they secured the conductors to the studs with.
Defiantly would be wrong.

I don’t see it Joe. What gives?

3 or more cables with 2 or more current carrying conductors must be derated if installed through the same hole without spacing present. The firestop caulk prevents the spacing. NEC 334.80

Me too

Even if it’s through only one stud?

One other thing. How do we know they are through the same hole? Each wire could have it’s own hole but covered up.

Reason 12 :I hate that extension cord stuff.

Bruce wins!

****E3705.4.4 Conductors of Type NM cable. ****Conductors in NM
cable assemblies shall be rated at 90°C (194°F). Types NM,
NMC, and NMS cable identified by the markings NM-B,
NMC-B, and NMS-B meet this requirement. The ampacity of
Types NM, NMC, and NMS cable shall be at 60°C (140°F) conductors
and shall comply with Section E3705.1 and Table
E3705.5.3. The 90°C (194°F) rating shall be permitted to be
used for ampacity correction and adjustment purposes provided
that the final corrected or adjusted ampacity does not exceed that
for a 60°C (140°F) rated conductor. Where more than two NM
cables containing two or more current-carrying conductors are
installed, without maintaining spacing between the cables,
through the same opening in wood framing that is to be fire- or
draft-stopped using thermal insulation, caulk or sealing foam,
the allowable ampacity of each conductor shall be adjusted in
accordance with Table E3705.3. Where more than two NM
cables containing two or more current-carrying conductors are
installed in contact with thermal insulation without maintaining
spacing between cables, the allowable ampacity of each
conductor shall be adjusted in accordance with Table E3705.3.

Joe could you explain what is meant by spacing.
(sorry but I am still learning romex)

It’s a judgement call. Rule of thumb to ensure compliance: no more than 2 conductors per hole.

Here’s some ICC commentary:

“The allowable ampacity of branch circuit conductors
varies not only according to the ambient temperature
surrounding the conductors but also according to the
number of current-carrying conductors in a raceway or
cable or in close proximity. Where multiconductor cables
(such as nonmetallic sheathed cables used in
residential wiring) are stacked or bundled together for
24 inches (610 mm) or more without maintaining spacing,
the allowable ampacity is reduced according to
the factors in Table E3705.3. For example, the allowable
ampacity of size 12 AWG copper THHN conductors
(found in nonmetallic sheathed cable) used with
90°C terminals is 30 amperes. If several of these cables
were bundled together for 2 feet (610 mm) or
more such that seven current-carrying conductors
were in the bundle, then the allowable ampacity would
be reduced 70 percent to 21 amperes (see Commentary
Figure E3705.3).
In some cases where the allowable ampacity is reduced,
either a smaller circuit breaker would need to
be installed or the conductors would need to be installed
with sufficient spacing between them and not
bundled. Some judgement may enter into the interpretation
and enforcement of this code rule because in
residential loads there is so much diversity in the
amount of current use in the branch circuit conductors
and in the duration of operation of the loads. To drill
one hole in the top plate of the framing above the
panelboard and run all the branch circuit cables in a
bundle for 2 or 3 feet (610 or 914 mm) into the panel
would be a code violation. This is not a good practice,
because the heat developed in the current-carrying
conductors cannot readily dissipate. Spacing should
be maintained or the allowable ampacity of the conductors
would be reduced.”

When you see (2) NM-B cables going through a hole, technically, it should be derated. Most romex, now, is three conductor.

It definitely is a judgement call. You can always count the number of outlets on the circuit as well as measure the total amount of amperage.


Sounds complex as I do not think there is a real rule on number of conductors in conduit unless I am wrong on that or number allowed in a junction box unless it constricts movement.
I can see the heat thing being a factor however.Not sure I see myself calling out but as I said I may be wrong.

You would be surprised on the number of electricians who think the same thing.
Table 4 in the back of the NEC gives the amount of fill for whichever type of raceway you are using. Just figure out which wires you are using, add up the total area (square inches) of the conductors, derate for the number of current carryong conductors you are pulling and you can figure out what size pipe. J-Boxes have their own percentage fill table.