poke holes in my electrical plan please

[TDKPE]

<p>Not sure.&nbsp; Each conductor entering the box counts as one, times its box fill volume (2 in^3 for 14 gauge, 2.25 in^3 for 12 gauge, etc.), except for conductors that pass through unbroken (each conductor counts as only one conductor, even though it enters and exits), and EGC's, which also only count as one (the largest one counts, times 2, 2.25, etc.), plus devices, clamps, etc.</p><p>So a 4-way intersection (for example) of 14-gauge&nbsp;conductors with ground counts 9 conductors times 2 in^3 per conductor, plus any clamps and/or devices that may be present multiplied by their respective box fill volume.</p><p>I'm doing this from memory, so if I missed something or got something wrong, someone please give me one of these.&nbsp;
<br></p>

[mound]

Nice memory!

So that would mean I could fit up to eighteen #12 splices inside a 42 cubic inch box.   But if I think I'm counting right based on the image I just posted, I would need to be able to splice 48, which means a bigger box.. Right? 6 circuits (each has 2 conductors) in a 4-way split at each junction = 48 splices (assuming the EMT itself is ground)

So am I right I'd need a box with at least 48*2.25 = 108 cubic inches? That can't be right.. That'll mean a much bigger box!

[srv52761]

<p>

I've got all my parts gathered and laid out on a big table to organize the install. &nbsp; All the boxes and covers I got look like the ones TDKPE showed earlier and you wrote about. &nbsp;I started asking myself, well if I'm using a dedicated ground wire, that means I should use it "across the board" as if the whole system were being done in PVC and plastic. Right? That would mean bonding the ground wire to the box, and the box to the green screw on each receptacle (or is that overkill?)... With #10 wire.. &nbsp;As I started thinking about all that extra wire and wasted space and time, in this otherwise sea of metal tightly connected to each other, I'm thinking maybe you're right that in my home shop where the connections won't be falling apart, abused and ignored, if NEC says an all metal system is a good ground, I should trust that.

If I go that way, there would be literally no green or bare ground wire anywhere in the system?

Which brings me to a comment you made in the older thread;


How does one determine if the EMT is "sized appropriately for the conductors" ? &nbsp; All but one of my circuits are 20amp (#12 conductors), one is 30amp (#10 conductors) and I was going to use 3/4" EMT for the raceway and 1/2" EMT for the drops. &nbsp;Is this sized appropriately?

Thanks!

</p><p><br></p><p>More than adequate.</p><p>https://www.nema.org/docs/default-source/technical-document-library/steel-conduit-and-emt-proven-to-meet-the-nec-reg.pdf<br></p><p>Wrt your concerns about # splices, don't.&nbsp; Draw a picture of your box, identify if it is a continuous wire passing through or not,&nbsp;and let the Construction Monkey calculator do it's work.&nbsp;&nbsp;</p>

[mound]

<p>
</p><p><br></p><p>More than adequate.</p><p>https://www.nema.org/docs/default-source/technical-document-library/steel-conduit-and-emt-proven-to-meet-the-nec-reg.pdf<br></p><p>Wrt your concerns about # splices, don't.&nbsp; Draw a picture of your box, identify if it is a continuous wire passing through or not,&nbsp;and let the Construction Monkey calculator do it's work.&nbsp;&nbsp;</p>

Thanks!
I've drawn a picture and the construction monkey tool is great, but I've been confused about counting the number of splices to enter into that calculator. 

If I want to run 5 20amp circuits and have all 5 of them be accessible at all drop points,  each of those is two conductors, so that's 10 conductors per circuit times 4 (because each is split 4 ways) and so if I enter 40 into the Construction Monkey calculator, it tells me I need 90 cubic inches.  (40*2.25)

That's far bigger than a 4-11/16 square box. Anything much bigger than a 3-gang gets expensive real quick, so I may have to change my plan assuming I'm counting splices correctly

[MstrCarpenter]

<p>Stop counting splices! How you connect the wires&nbsp;has&nbsp;nothing to do with box fill calculations. If you pull an extra pair of wires for possible future use into a box, they're still "conductors". Count all conductors coming <i>i<b>nto</b> </i>the box by gauge. (For this application all wires come into the box.&nbsp;Wires don't really go "out" of a box, but if there's some that come in and&nbsp;go right "out", unbroken, you can count it as one conductor.)&nbsp;</p><p><br></p><p>Because all the grounds count as only one conductor, and sometimes things can happen when it's highly&nbsp;desirable for the equipment ground to be a lot better conductor than me, I would include a wire designed to ensure it always is.</p>

[mound]

Stop counting splices! How you connect the wires has nothing to do with box fill calculations. If you pull an extra pair of wires for possible future use into a box, they're still "conductors". Count all conductors coming into the box by gauge. (For this application all wires come into the box. Wires don't really go "out" of a box, but if there's some that come in and go right "out", unbroken, you can count it as one conductor.)

I'm only counting "splices" because the box fill calculator (https://www.constructionmonkey.com/calcu...al/boxfill) is specifically asking for "number of wires spliced inside the box" which is referring, I think, to the number of wires that enter the box that aren't passthrough or terminating on a device. Which for my application, if there are 5 circuits each splitting off 4 ways inside each box, that's 40 wires inside the box, which is way too much for a 4-11/16" square box.

thanks!

[TDKPE]

<p>I would seriously reconsider running them all through a single box, from a single conduit. &nbsp;If they’re splitting off to go north and south (for instance), then consider running a north branch and a south branch. &nbsp;Reduces the number of conductors in a given conduit for derate purposes, and probably makes a cleaner installation, though that’s impossible to tell from a block diagram of course.&nbsp;</p><p><br></p><p>Something to consider, at least.</p>

[mound]

<p>I would seriously reconsider running them all through a single box, from a single conduit. &nbsp;If they’re splitting off to go north and south (for instance), then consider running a north branch and a south branch. &nbsp;Reduces the number of conductors in a given conduit for derate purposes, and probably makes a cleaner installation, though that’s impossible to tell from a block diagram of course.&nbsp;</p><p><br></p><p>Something to consider, at least.</p>

Hah this is <b>exactly</b> the same conclusion I came to just last night! Two runs - one for the ceiling stuff the other for the wall stuff. Suddenly everything works out with normal sized boxs lol..  Was trying to be too fancy I suppose.

[srv52761]

<p>

</p><p>I would seriously reconsider running them all through a single box, from a single conduit. &nbsp;If they’re splitting off to go north and south (for instance), then consider running a north branch and a south branch. &nbsp;Reduces the number of conductors in a given conduit for derate purposes, and probably makes a cleaner installation, though that’s impossible to tell from a block diagram of course.&nbsp;</p><p><br></p><p>Something to consider, at least.</p><p>

</p><p>Would also consider not making all three 120's available at each drop.&nbsp;&nbsp;</p><p>My shop is rather small, 16x12.&nbsp; I made one wall my power tool wall and one wall my hand tool wall.&nbsp; I&nbsp;put two 20 amp circuits and my 240 circuits on the power tool&nbsp;&nbsp;wall,&nbsp; &nbsp;and&nbsp;one&nbsp; 120 volt 20 amp on the hand tool wall and put a couple overhead 120's in the ceiling.&nbsp; I have never overloaded any circuit.</p>