How Many Electrical Wires Can I Put in Conduit? | Conduit Fill Calculation

[@DIYApprentice]

I hope this information is useful. I always try to "look before I leap" when I'm doing these DIY projects. Something seemingly as simple as installing and filling conduit could have a dangerous outcome if done incorrectly. *Please leave a 👍 and share the video!* 👉 Visit our website ► DIYApprentice.com 👉 Click to Subscribe! ► bit.ly/2pEBg3m 👍▬▬Follow Us on Social Media▬▬👍 ✔️ Facebook ► bit.ly/2pAY8S3 ✔️ Twitter ► bit.ly/2G7mRDz ✔️ Instagram ► bit.ly/2ILEKII 🔧▬▬Tools and Materials▬▬🔧 ✔️ DIY Apprentice Recommended Tools and Materials ► bit.ly/2T5psFw ✔️ NEC State Adoption Map ► www.iaei.org/page/nec-code-adoption 📷▬▬Video Equipment▬▬📷 ✔️ Camera used ► amzn.to/2GcpkOb ✔️ Lens used ► amzn.to/2Deu16S ✔️ Tripod ► amzn.to/2GbaM1c ✔️ RAM Suction Mount ► amzn.to/2Wz9PXh ✔️ Cyberlink PowerDirector ► bit.ly/2jTwGxT ✔️ Adobe Photoshop ► bit.ly/2V7nyUX ✔️ Camera Slider ► amzn.to/2WtD7GW ✔️ Deity V-Mic D3 Super-Cardioid Directional Shotgun Microphone ► amzn.to/2LI1lf7 **This video was recorded in 4K resolution, so modify your settings accordingly if desired for better image quality** Disclosure: This video contains affiliate links, meaning, at no additional cost to you, I will receive a commission if you click through and make a purchase.

[@fistpunder]

Thanks for the in depth detail. This goes much more into the design specifications and codes than I expected. Great reference. And you back it with source of materials presented. Top notch video for technicians and those ready to do a little math to get it properly done.

[@DIYApprentice]

Glad you found the video useful. Thanks for watching!

[@ericpelayo9872]

Nice explanation, simple and detailed, thank you 👍🏼

[@DIYApprentice]

Thanks! Appreciate the feedback.

[@jeremiahrex]

I appreciate you putting the code screenshots up. A video like this is a great primer to get me up to speed but I always like to dig in further. Plus NEC 2020 wouldn't tell me about the helpful online tools. Thanks for the video!

[@DIYApprentice]

Glad this video was helpful. Thanks for watching!

[@lisag3495]

Super helpful. Thank you

[@vibesmom]

Super informative thank you!

[@DIYApprentice]

Thanks for checking out the video!

[@vgmijpn8ball]

I just learned, even though you can fit that many wires, the installation won't meet code unless you derate your wires per NEC 310.15 c 1. 12 gauge won't support 20 amps, and 14 gauge won't support 15 amps as is normally thought

[@DIYApprentice]

Yes, I briefly mentioned "de-rating" at 8:04 as a factor to consider.

[@TheJimsokoloff]

If you're using THHN (a 90°C conductor), you derate from the 90°C rating in T310-16. In that table, 12 AWG THHN "starts" as a 30 A wire in the 90°C column, so even if there are 7-9 conductors (70%), that yields 21Amps for multiple-conductor derating purposes, and 14 AWG THHN would be 25 * 0.7 or 17.5 Amps.

[@enufots4621]

Nope, don't get it. You need to explain what the percentage of fill limit is? A 2 wire has a 31% fill limit...what does that mean?

[@DIYApprentice]

@2:07: Fill % is based on the cross-sectional area. Two conductors or cables can fill no more than 31% of the cross-sectional area. Each wire or cable has a specific size that's used in the fill% calculation. Hope this helps. You may want to re-watch the video.

[@hippo-potamus]

I didnt understand a damm thing you said mate. Talk about over complication subdividing everything to individual wire with jargon terminology and you total inability to just break the information down into laymans diy terms so we can understand. Most of us here just want ot know how many sets of 14/2, 12/2, or 10/2 we can fit inside a half inch emt conduit. The search continues.

[@DIYApprentice]

Sorry that what I explained didn't come across clearly; I haven't received similar feedback from other viewers. It sounds like your primary complaint about the video was that I didn't go into depth about fitting residential cable in conduit, which is actually referenced around the 3:30 mark. There are all sorts of possible combinations, which is why I didn't get too specific and just mentioned cable diameter being a factor. Most installations I've come across run individual THHN or THWN wires in conduit. Here are the major diameters I was able to find for residential cable that would have to be included in the calculations: 14/2 (0.36"), 12/2 (0.4"), and 10/2 (0.49").

[@hippo-potamus]

@@DIYApprentice Are they running solid or stranded THHN? Another thing that's not really explained well in the NEC is if "conduit" specifically means the pipe from box to box, I'm just trying to run a couple outlets so I've read others say that a simple drop run isnt considered "conduit" but rather just a protective sleeve in which case romex is acceptable and the heat concern isnt really applicable. But I guess the code and your reading assumes the use of THHN or the like single cables. Another concern is supposedly solid cable is able to support higher ampicity so Im not sure if I do run stranded THHN I should use 12g THHN instead of the 14g I wanted for simple 15amp outlets. Appreciate your feedback.

[@DIYApprentice]

​@@hippo-potamus I don't want to speak out of turn, since I'm not an expert, but it seems like stranded vs. solid comes down to personal preference when it comes to residential wiring. Stranded is easier to pull through conduit for longer runs that include bends, while solid is easier to push through conduit; I've only ever used solid wire. My understanding is that solid is able carry more current than stranded. Personally, I would go with solid, but I don't think the difference between the two for simple residential wiring is significant enough to warrant 12-gauge wire if stranded is chosen for a 15-amp circuit. Distance of the cable run can be a factor, with solid performing better over longer distances. Chapter 9 of the NEC, which I referenced in the video, lists several conduit types: EMT, RMC, PVC, Liquidtite, FMC, IMC, etc. It's basically the pipe that protects the wire or cable from damage.