did you know that using pancakes most of the time is a code violation let's break in
so pancakes are something that we use out in the field to hang light fixtures sometimes we have a
stud that we have to mount something there's wood and we don't have a cavity or a chase
to mount a box to that's really deep that we can get all of our conductors into it so sometimes
we'll have to drill through something and mount something like a pancake and put our wires in that
way so these are uh essentially just a fix for a weird situation that we run into in the field all
the time but in code we are supposed to calculate how many conductors we can put in any kind of box
so if it's an outlet box for a receptacle there's certain depths of receptacles there's different
sizes but we have to account for the depth of that and wire bending space to actually get a device
and and the conductors put into the box and so these are really tiny i mean if you look at this
you really can't fit much inside of this so imagine hanging a light fixture and
trying to fold all the conductors and smashing them back in there
a lot of times things get pinched and things get damaged or something doesn't seat right and
water will get in there's all kinds of different reasons why using these kind of sucks so let's
first look at what the national electrical code says about this we're going to be looking in
314.16 it shouldn't matter what year you're looking at in the last few years but i am looking
at a 2020 national electrical code so we're in 314.16. what it says is boxes and conduit
bodies shall be an approve of an approved size to provide free space for all enclosed conductors
in no case shall the volume of the box be less than the fill calculation as calculated in 314.16b
so 314.16b says box fill calculations and there's a few different like subsections within b there's
uh number one which is conductor fill so each conductor has a certain volume that we have to use
based off the size of the conductor to calculate how many conductors we can fit in this thing
every time there's a clamp so you'll notice that this larger four inch pancake doesn't have any
clamps on it but this thing the way it's designed is that you can just knock one of these things out
you don't actually have to put a connector into it you just knock one of them out slide a conductor
in there and this clamp tightens down over it so these clamps actually have a volume allowance
as well so if you have clamps in something whether they come manufactured like this or it's something
that you're fixing to a box you have to add an allowance you basically have to de-rate
the volume of the box based off of that and then another thing is if you have multiple equipment
grounding conductors so say we ran like four number twelve or four uh pieces of twelve two
romex into this thing well if you have up to four equipment grounding conductors or grounds you can
count all of them as a single conductor that's kind of cool anything more than four you gotta
count each one individually or any number over four you have to count individually so let's break
into this a little bit and do the calculations and figure out what's going on there's a table table
314.16b which corresponds to everything i just talked about the conductor fill the clamp fill
equipment grounding conductor fill everything that i'm going to use to calculate i just want to talk
about this table so that you understand where i'm getting these values so this says it is the volume
allowance required per conductor and you'll notice on the left hand column it says size of conductor
in awg so if we're using 12.2 romex those number 12 conductors are going to be worth a certain
volume and if you go all the way to the right that column on the right that says inches cubed we're
not using centimeters cubed we're in america so we're using inches cubed or cubic inches
you'll look across from number 12 and you'll see 2.25 that means that each conductor
that is that size that is number 12 is worth 2.25 cubic inches of this box this box is a four cubic
inch box so you can already kind of see where we're going with this one conductor out of that
three conductors that are in that 12 2 is 2.25 we add a second conductor that's 4.5 so we've already
gone over the allowance we haven't even taken into account that we have clamps here and these clamps
are 2.25 as well so this table is where we're getting the numbers if you look at number 12 and
number 14 those are the examples that we're going to be using uh in a couple of these different
scenarios that we talk about but number 14 you can actually use two cubic inches rather than two
and a quarter cubic inches all right so let's look at our first example this is a three inch pancake
this three inch pancake says that it has a 4.0 cubic inch
volume if we look at our table we've got a number 12 conductor so let's say we're going to run
12 2 which ends up being three number 12 conductors then number 12
is two and a quarter per conductor so that means we've got 2.25 plus 2.25 plus 2.25
so that's 6.75 cubic inches worth of conductor that we have coming into this box if we're
running 12 to romex so 6.75 cubic inches this is four cubic inches but because we have these
clamps we actually have to take it down a volume allowance so this 4.0 cubic inch box minus
2.25 ends up being 1.75 cubic inches so this box is way too small we can't even per code fit one
piece of 12-2 in this box what about if we did a 2 so if we have 14 2 that's three number 14s
those according to table 314.16b for number 14 we go across and we get two
cubic inches per conductor so in that situation 14 2 is three conductors that are two
plus two plus two hot neutral ground that's still six cubic inches so there is no way we can use
these and get away with code you could put fixture wires in them like really small fixture wires and
get away with it because each one of those are even going to have a lower allowance you know
number 18 is going to only be 1.5 cubic inches so 1.5 1.5 that's three plus another 1.5 that's 4.5
this is only four cubic inches though so you still can't do that and it's got the clamps in it
now you can take these clamps out we could absolutely just take them out and get the four
so that we don't have to do another uh allowance and you like further derate this thing but
these things are completely against code almost every situation you could possibly use them in
all right now let's do an example of a four inch pancake i've got three variations
of a four inch pancake here they all look pretty similar this one's got this little
kind of like bump on the inside where we would put our grounding screw so it's going to have a
little bit less volume in it maybe than some of the others we've got one here that says that it
is 5.8 cubic inches 5.8 cubic inches now before we even go any further we know that from our example
with the 14 2 that we were at six cubic inches six cubic inches for all three of those
number 14 conductors so we know if we do the 12 2 that we're at 6.75 cubic inches for all of the
conductors so already we can see that neither the 12 2 or the 14 2 is within code even for
this 5.8 cubic inch pancake so what do we do well if you notice these three pancakes are all
different they're pretty much the same but they do have different stamps on them and if you notice uh
just barely you can see that there's a little bit of a difference in the uh thickness of these boxes
it's barely noticeable right like there's barely any kind of difference but there is a difference
and that's why they have just slight variations in manufacturing they're going to have slightly
different numbers so we can put the 5.8 cubic inch aside that leaves us with a six cubic inch
and then we've got a what is this 6.5
okay well now we're starting to make some headway we've got a six cubic inch and a 6.5 cubic inch
so let's do an example we know with our 14 to six cubic inches so we could actually use this
six cubic inch box with 14 2 specifically what about the 6.5 well the 6.5 is still
not big enough to use 12 2 with it would need to be 6.75 so they would need to add like a little
bit of depth to these but these are the the the depth of most drywall like this is going to be
perfect if you butt half inch drywall up to this so you can't really go that much deeper what you
could do is you know like i guess hollow the wood out behind it so you could get it to sink
back and then you could make a little bit deeper box but that kind of defeats the purpose because
nobody wants to do that so neither of these boxes none of these three four inch pancakes
or this three inch pancake will allow you to use twelve two and that's one piece of twelve
two romex that's not adding one coming in one going out two coming in you know that is one
piece of twelve two that comes into this box and lands and terminates on a fix some fixture wire
we cannot use a four inch pancake by code at least we can use mountain fuel all we want i suppose
but you can't use them to code and it actually be to code so the only situation that actually works
for any pancakes is when you use 14 2 because you have 6 cubic inches worth of conductor
you have 6 cubic inches worth of box but you have to make sure that you don't have a 5 cubic inch
pancake you need to make sure it's at least a six or a six and a quarter but that is the only time
that pancakes can work but if you're using light legs you're doing led stuff a lot of people do run
the entire circuit in number 12 and then you know any receptacles or anything like that are usually
run at number 12 and a lot of times they'll take switch legs and they'll come out of the switches
and go up to a fixture with number 14. so in that case if you only have one conductor coming into a
four inch pancake that is six cubic inches greater only then is this whole thing to code now that is
box fill so that's how many conductors we can put in a box if you're curious to learn more
about conduit fill which is a very similar situation i have an entire video right here
you should click on and it teaches you everything you need to know about conduit fill and if you
want to watch the short version we actually have a like short version that's just a few minutes long
the long version has lots of explanations and details so there's a lot of value to it but if you
want to watch the short version you're short on time click down below and you can watch that one