How many wires can you stuff in a box, and how do you count them? This video goes over the National Electrical Code requirements of 314.16, based on the 2020 NEC.
you really got a few hundred million likes but most people hit the thumbs up button twice to show how much they love you. i only hit it once though..your alright lol
For what it's worth, here's a little tip/note regarding the 2020 box fill updates for EGC's. Basically, once there are 4 or more EGC's in the box, just divide the total by 4 to get the required allowances. That is, for your example with 46 EGC's in the box, there is no need to think, "Well, there's 1 allowance for the first 4, and 42/4 allowances for the rest". Instead, you can just calculate 46/4 for the total EGC allowances needed, as the math works out the same, to 11.5 in this case. I don't know about anyone else, but that wasn't obvious to me at first, but now that I know it, it simplifies things a little, mentally speaking. Now, if I ever actually come across a box with 46 or more (or even many less) EGC's, I'm outta there! :)
"Party foul" lol. I'm going to write that in an inspection. "Item #14 turn the receptical under the sink that is facing up onto its side. This is not a violation but a definite party foul and should be corrected."
Glad to see you on my learning screen again! I’m also glad to see that the second paragraph of the clamp fill section might get struck. I never understood it either.
It’s very odd. We have ran into a pissing match at work on how to calculate this and over the I went through the internet looking for information and directly to your RU-vid looking for this video…and tadah you made. Universe is mysterious.
As a fellow electrical instructor, I use this video as a review before a box fill test. By the way, practice makes better because perfect does not need practice. just something I teach my students. Thank you for your continue support of the trade. God bless.
What a mess in the last pic, Mr Ryan, I will never do that wow i have seen a lot of videos about gutters calculations or u pull, angle pull and so forth but this is is insane, wow. Spechless, but thanks for all your videos sir, always following you in all your videos. Great
You just earned a new subscriber! I love your attitude and ability to teach. Side question for ya. With all this box fill mentioned, what is the wire length they use to get these calculations? I know other places in the code mentions length minimums, so do they go off that minimum? Thanks for making such great content!
Actually, the extension ring shown at the beginning is for a 4-11/16 square box, hence the larger capacity. You can tell by the mounting screw locations and the ko placement is farther apart. In Chicagoland, we refer to that size jbox as an 11b box.
Hi there Ryan. Thank you for all your videos and content. I know this is an older video but really was a great easy to understand explanation about box fill. I recently shared the video link with a friend and he asked about the specific reason for 22.5 volume. After watching the video again myself to see what he was referring to I realized I either missed it or that you did not come back to it. At you mention that there is a very specific reason for the 22.5 volume. Would you be able to explain what this reason is? Thank you.
As a commercial Electrician I’ve NEVER calculated box fill. I always oversized my box’s. I always use deep box’s unless the wall is too shallow and IF more than 2 MC cables in a box I up it to 4-11/16 deep box. ALL home run box’s get 4-11/16 box whether one MC or 4. ALL switch box’s get 4-11/16 box with 3/4” conduit to above ceiling.
Talking about conductors that just pass through boxes... yeah the code needs to address that. So needed to covert from a regular indoor wire to an outdoor conduit. Obvious I wasn't going to just have the wire go into the conduit, although I didn't check if that was to code (this is my house and I'm not an electrician, although I did consult one), I've only ever seen a transition to conduit in a box, so that's what I did. I used a metal box as nothing but a pass through, no splices no nothing. Then when I went to show someone the box I got and unpleasant surprise, the entire metal box was energized and ungrounded. In spite of the issue my electrician friend said the box was to code, but he thought that it was stupid. As it turns out, even though I couldn't find any marks in the romex one of the screws that seal the box had some how managed to penetrate the insulation on one of the hot wires. Well sufficed to say I opened the romex and grounded the box properly! All metal that can be in direct contact with a live wire needs to be grounded!
Also you mentioned single conductor do not have bending space requirements. Where can I find this or how would a test question ask this! Thank you for everything you do. You energy and information has saved lives and money
Sorry people with fat fingers should not attempt to type on cell phones. Wish the NEC would address the extra deep 120 volt receptacles with USB &/or cell phone charger ports. At the hospital that I retired from we had Hospital grade tamper resistant ones that were over 2.5" deep. Maybe they should supply a rubber maker with each 10 pack of them. Only kidding. I always used a deep box and never used duplex switches for any new work. Great to see you back. Can remember back in the 1970 when GFCI receptacles came out and you had to install a 1" deep wiremold box onto wall case to get them to fit.
How can you divide the EGCs as 4 if they are #12s? Im confused because wouldnt it be ¼ of 2.25 cu in since there #12s? Or are EGCs counted as 2.00 like a #14 is no matter what?
Hi Ryan, good video. You have or know a reference to why the EGC is only counted as a unit in the box fill calculations. In new versions the change adds 1/4 unit after the 4 leads but can still cause a fill problem, from my perspective. The only reason that comes to mind is that since they are not current-carrying conductors, they do not add additional temperature in a box. Any idea?
As a facilities manager, hashtag not an electrician, I find the maximum allowable conductors in most boxes to be way, way more that is reasonable to work with. Fortunately, I don't often run into these maximums. And it goes without saying that a lot of this is just my own lack of skill.
i heard from somewhere else that heat isnt the real reason we have conduit fill. i think if i remember correctly its simply because it would be too hard or troublesome to pull too many wires whether there's damage or not especially in 360 bends. i think they might have mentioned something about noise or feed back so maybe having copper wires all close to eachother could induce something but i think there are grounding methodes for certain stuff like that
Regarding Internal Cable Clamps: at 16:38 you say that it’s not too often that we have to deal with internal cable clamps - but what about non-metallic boxes? I know that if you ask 20 electricians whether the clamps on NM boxes count 19.5 would say “no!” But, when you look at the information provided by, e.g. Carlon, you can see that they believe the clamps do count and need to be deducted from the volume available. See question at bottom of page 3: carlonsales.com/techinfo/faqs/FAQ-ZipBoxes.pdf “The volume inside an outlet box does not include any deductions for integral clamps. The clamps are removed from the box when the volume is determined by UL. Therefore a single deduction in the NEC is required for the space the clamps take up inside the box.”
I would have to look that up in my 1978, but I don't believe the NEC has ever had such a restriction. In UL Product Cateogry QCIT it specifically states that "one or more" can be uaed.
for code section {314.16 B 1} each conductor that passes through the box without Splice or termination Shall Be counted Once { We count foe the entire wires passing through Once {or} we count for each individual conductor Once?!!!!! my understanding is for each individual conductor we count ONE
Wait a minute, you're telling me there are NO minimum bending radius limits for individual conductors under 1000v? Is that just for 6awg and smaller? Or all conductors under 1000v?
I've always been curious why the right side of (t)314.1(a) allows for a greater capacity than is calculated in (t)314.16(b). There isn't, to my knowledge, any ability to "round up" ie.... 4 X 1/4 round/octagonal box allows 5 - #8s. 5-#8s is 15in3. Box allows 12.5in3.. There are a few examples of this... Why? Anybody have a code reference why this is allowed? Seems that it should be rounded down and only 4 conductors allowed since you can't have a partial conductor in a box. Besides devices, clamps, etc. makes the right side of (t)314.16(a) garbage anyway. Seems like it should be removed IMO.
hahahaha I ran into this in Malls on many occasions 12x12x4 pull box FILLED several conduits and multiple 12 MC's or 4x4xbox with 5 extensions on it..... Glad I don't do that anymore
You supposed that 8 AWG wire would be going to a 50A receptacle around 21:35 I definitely think 6 would be more appropriate. Great video other than that
I will prefer if large devices coun for 3 (some people want to save 15 cents instead of doing something right), also I did not know that it was illegal to use a different type of screw (drywall screws) in nonmetallic boxes to hold the devices, I see that so often
