Sizing an Electrical Box

In this video we discuss how to size the minimum electrical box required as per 12-3034 in the 2018 Canadian Electrical Code. Please note this video is intended as an instructional aid, and all inquiries should be discussed with your local jurisdictional authority for clarification. Thanks for watching!
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[@martintassin4510]

Probably meant to say 4 X 2 1/8 on your last example. Thanks for posting!

[@schulerruler]

Haha yup. Thanks for noticing. I'll leave that as my check to see who watches to the end!

[@japhetozogbuda725]

Thanks for pointing that out

[@malayekk6522]

I did watch it until the end, and noticed the same thing, but no biggy. Wonderful video right on point, please keep making more videos, especially voltage drop based on new math in 26th edition. On all aspects of calculations, perhaps one video for formula. ​@@schulerruler

[@InServiceForTheGoodofAll]

I’m going to rewrite my Red Seal in April .. these clear easy to follow videos are going to help me prepare and become more confident , thank you !

[@schulerruler]

Happy they are helping! Good luck. The little handbook that comes with the codebook is a great study tool as it covers a lot of different aspects! Also study up on your HVAC. I have two videos that cover the sequence of operation for a basic, and mid efficient furnace that will help review the parts and pieces.

[@soldatheero]

@@schulerruler Will be watching tomorrow after my TQ at SAIT

[@upallnight4946]

Im about write in three weeks and your videos load me up with knowledge, kinda like Neo in the matrix. 😂😂Amazing videos

[@austinarbuckle9823]

You explained this 10000x better then my college professor! Thank you

[@schulerruler]

Thanks for the support!

[@bizza295]

you were my teacher at sait back in 2014, having to redo schooling back in ontario now. this helps so much. so happy i found this channel.

[@schulerruler]

That was a few years back! Thanks for reaching out! The name is definitely familiar!

[@athanrbles7932]

Thank you, Sir, very helpful, Electrician from the Philippines :)

[@DarksidePride]

Great way of explaining the code booK! im writing my IP in a month and this is helping!

[@Al-wu8is]

Simple and Clear. Perfect job.Thank you you helped me a lot.I love all your videos.

[@schulerruler]

I'm happy to hear they help!

[@lliammclachlan]

Thank you so much this was a huge help I was having a hard time with the concept before I watched your vid

[@schulerruler]

Happy it helped my friend!

[@ic_0129]

Thank you! This was very helpful!

[@lucasdaniel8186]

Legend, thank you for simplify.

[@big4m20]

I appreciate the videos, thank you. You're a master of your craft.

[@schulerruler]

Thank you for your encouraging words and support!

[@lylewatts6370]

Thank you for the info. Good to know and how to figure it out.

[@schulerruler]

Thanks for watching!

[@spelunkerd]

I thought I understood this pretty well, until I had to do an example with a GFCI measuring 3.4 cm deep. 12-3034(3) seems easy. 3.2sq cm X 3.4cm= 108.8 ml reduction of the box volume. Fine, we've accounted for the entire volume of the GFCI inside the box. Having accounted for the entire volume of the GFCI, do we still need to ALSO add two more conductors for the GFCI receptacle? As a back-of-the-envelope calculation for a typical AWG14 upstream box with insulated ground wires (total 6 wires+1 connector), this works out to needing 256.4 ml if I don't add two extra wires, and 305.6 ml if I also add two extra wires for the GFCI. Big difference! Does the remark "Except as specified by subrule 3..." in 12-3034(2) tell us we don't need to add the extra wires if we account for the entire volume of the GFCI?

[@rickygrand1405]

Very informative, great lesson.

[@TTVISeeYoux]

Great video! helped a lot. Just a question were did you get the mL for each conductor on table 22? I cant seem to find it, Thanks!

[@schulerruler]

Thanks for the support! The mL are listed on the right side of table 22. Example a no. 8 has an occupied volume of 45.1mL.

[@alaaeddinjoumaa4269]

Hi Can you please advise on how to size breaker, panel and fuses. Thanks

[@saeedhasanpour2523]

Thanks for your great video but im still didn’t get why you count 4 #12 conductors in last example?

[@muthukumarkanakasabai8454]

Nice explanation

[@jayswitzer9871]

Just took a Class with the gentleman who publishes the illustrated CEC and 12-3034 2(b) - one conductor for every insulated pair with a cap. And that is how we are doing it in Code Class. So your six wires as per the code is only 3 wires, plus 1 for every pair of caps.

[@schulerruler]

Each conductor that enters OR exits is one each. The only time it does not count is if no part exits the box. A pair of conductors, with each exiting via a raceway or cable would count for two conductors. The wire nut would not count until there was a distinct pair of them. If each of the six conductors enters or exits they count. Six "enter", six "exit" = six conductors for enclosure sizing purposes. Plus the one conductor equivalent for the three wire nuts as it is one full pair.

[@jasonshlimon6783]

Thanks u help me alot thank u again

[@diyguy446]

Soooooo good... well done bro... one question that you didn't address... how do the bare ground wires count in this calculation?

[@schulerruler]

The rule only ever specifically mentions insulated conductors. It certainly doesn't hurt to count them, but not required.

[@larrys8086]

very informative...thank you . However, it's a bit misleading in that you mention that receptacles and switches count as 2 conductors each. The conductor calculations change if you install devices that are deeper than the standard 1" receptacles and switches. Items such as dimmer switches and GFCI's are deeper than 1". The formula to calculate the box fill for deeper receptacles is 82 x the depth of the receptacle (in cm) div by 2.54. For example..a receptacle that is 4cm deep (measured from the yoke(mounting bracket) to the back) would be 129 ml.

[@schulerruler]

I intentionally created the images to reflect standard devices, but you are correct, for larger devices it is a different calculation. Especially those nasty USB slot receptacles!!

[@spelunkerd]

Nice review, this is hard to remember if you don't do it every day.

[@abdualchaban5508]

super helpful thank you

[@ashishnarula8596]

hello very helpful video but in last example of different sizes of conductor calculated conductor area is 250 .xx ml why we take box in octagonal less than 250 you take the column one 245ml ( 15 Inch) can u please explain a bit thanks

[@JesusCruz-wt2zp]

Can you do a video about when does neutral count a CCC...thanks

[@schulerruler]

Hey thanks for watching. A true neutral won't count as a current carrying conductor, however an identified could. For example if you had a 120V two wire circuit, both the hot and identified would both count. Check out the video below, as it walks through a bit of the why, as well I have a video on Edison three wire in my "theory" videos playlist. kzbin.info/www/bejne/ppfWnXd4h6yHaas

[@BuhlakeV]

What about for dimmers and GFCI? 12-3034 3) is messing me up and I need help!

[@lead2bfollowd]

hey quick question!! when there is a device present ( switch, outlet) do we use the largest conductor for caluclating the 2 conductors the code requires use to account for the device? or can we use the smallest wire for the volume calculation?

[@schulerruler]

It would fall under the same requirement as wire connectors. We would use the largest conductor sizes and take the device as two equivalent of that size.

[@nadirgabir3012]

Just wonderjng if Rule 12-3036, derermining pull box size is applicable to underground installation and concrete manhole? Or only for buildings?

[@ruanmorrell5983]

Hi there I was wondering if you could do a example of a tap conductors for 2 cook tops that are less than 7.5m

[@artemplatinoff1185]

It's hot == Swithed on/Under Load Wire nuts / connectors = cups for wires common guys

[@rubbersoul451]

Are you able to help? I was given a vague question and need some assistance, please. How many insulated conductors are allowed in a 2 gang device box that contains? 1-Single pole switch, 1- three way switch, 2-two conductor connection and 2- three conductor connection. I've tried everything, drawing it, counting it. I am so confused with the 2 - two conductor connection and 2-three conductor connection part. I am able to calculate box fill but unsure how to account for these to count as conductors. Thanks

[@schulerruler]

Each switch counts as 2 conductors, and each pair of wire connectors counts as 1 conductor. Without including the conductors themselves it sounds like 6 conductors of space are already utilized through your listed equipment as follows: Single switch on one strap = 2 Three way switch on one strap =2 Two x two conductor connections is 1 pair of wire connectors = 1 Two three conductor connections is 1full pair of wire connectors = 1 This makes 6 total. Deduct this from whatever box you choose and that tells you how many more you can stuff in the box.

[@MohHuzaifa]

Hi, Can you please advise me how to prepare red seal exam for industries Electrician - i am totally confused how to get that material for preparation

[@schulerruler]

Check out the red seal standards web site as they'll have a breakdown of the exam as well as the RSOS document outlining the expected work activities expected. For exam preparation, there are options through the CSA itself to access practice exams four a fee, as well as exam bank, also for a cost. I caution the exam bank as I've noticed some code questions are from previous code cycles. The small handbook that comes with your codebook is a great study resource as well as it covers quite a bit of information.

[@diymechanicalprojects10]

Hi how did you find 250.1 ml from table 23 4*2 1/2 oct

[@josho5177]

thanks! great vid

[@saifwaleed9784]

It's grate thank you very much

[@teabagolympicswithdaveurqu7137]

my new code book doesnt have that octagon size only 4x1 1/2 and 4x 2 1/8

[@schulerruler]

Yeah i made an error.

[@brianzhan4949]

thanks so much, it is clear

[@canjamm10]

Why is there no reduction for marrets switches or plugs from table 23, rather he adds to the wire count when there are switches, plugs and marrets

[@EricHuang-nw8sd]

thanks a lot!

[@yag3905]

Thanks

[@guoxutian9625]

Hope you become Canadian version of Mike Holt one day

[@farzadneshan6895]

Hi Sir I couldn't solve a question in my exam...it was... What box size for... 4 pair connections #12 and 3 pair connections #8 Thanks .

[@taghvaee]

Perfect

[@abouzarfallah7012]

how count bonding wires inside box?

[@schulerruler]

If they are insulated they count the same as every other insulated conductor. 1 for straight through, 1 for every insulated conductor that enters or exits. If they are bare conductors (uninsulated) they do not count, though you could count them as good measure, but it's not required by code.

[@abouzarfallah7012]

@@schulerruler if we have 3*14/2 and their bare bonding go in one wire nut and extend one of them to box and switch grounding screw how many is considered?

[@diymechanicalprojects10]

Should be 4*2 1/8

[@papag9127]

👍

[@randhasan]

the last question should be Octagonal 4*2-1/2 because is 250 ml ,not 4*1-1/2

[@schulerruler]

You are correct. I wrote down the wrong box unfortunately.

[@johnnyrod8661]

But, 4*1-1/2 is for 245ml. should the answer be 4*2-1/8 ?

[@druhill1796]

holey crap you need to help rewright the Hand book. Thank You

[@adilllo1]

The Octogon is 4x2-1/8 not ....1/2

[@schulerruler]

Yes, thank you. Sometimes mistakes happen.

[@adilllo1]

@@schulerruler I am doing a question now. I counted 57 conductors of #8 × 45.1 ml from T22 × 0.061= 156.8 cubic inch. The right box is 8×8×4. I don't know how they changed 156.8 cubic inch to 8×8×4.

[@schulerruler]

I'm assuming they are going off of standard trade size boxes and the next smallest would be a 6x6x4 which has an internal volume of 144 cubic inches which would be too small as you mentioned the required volume is 156.8 in³. An 8x8x4 would be the next largest at 256in³.

[@adilllo1]

@@schulerruler Is there somewhere to find those sizes in the CEC or just trade knowledge?

[@schulerruler]

Above a 4 11/16, it would be trade knowledge, or manufacturers catalogue sizes.