Wiring Question

[Shaun Wesley]

Quick question...
I am wiring a 100 amp subpanel directly next to my 200 amp main panel. I will be using four THWN wires, three #2 and 1 #6(ground). The space between both the subpanel and main panel is only one stud. Do the feeder wires need to be in a conduit or can they pass directly between the stud to feed the subpanel?

Thanks in advance for any insight you can provide.

[Rob Russell]

THWN needs to run in some form of raceway. Round conduit is 1 form of raceway.

Depending on the type of conduit you run, you'll need 1 1/4" or 1 1/2".

[Chris Padilla]

You might be able to find a nipple or a piece of rigid that long, Shaun, but, yeah, the individual wires need to go inside something for protection as Rob alluded to.

[Shaun Wesley]

Thanks guys.

I picked up 1 1/4 PVC conduit at the local BORG. I have never needed to use conduit before so this part is new to me. Since both panels are inset between the studs would you recommend I run the feeder cables in the conduit between the sides of the main and subpanel or out the top of the main and into the top of the sub? Or does it really matter? Also, should I reinforce the area at all since I will be drilling a hole in the stud large enough for the 1 1/4 conduit. Seems like a big hole...

[Rob Russell]

Is this all under sheetrock or is it open?

[Shaun Wesley]

It is open at the moment. Once I finish this wiring I will be hanging dry wall.

[Josh Mountain]

Yeah, I ran into the same issues with boring the studs for conduit. Not sure what area you'll need to get a copy of your city's boring and notching guidelines if they have such a beast. My city has such a document and breaks it down into load bearing and non-load bearing walls and how big of holes you are able to bore. Here a pretty good size hole could be bored with 7/8" of the 2x4 intact at front and back but on either side of both panels (for a setup like yours) and had to double up the 2x4s.

Get your hands on those documents if they got em, otherwise give your building inspection unit a call/stop in. Should be able to help you out.

[Roger Frazee]

Shaun

Before we all start replying is this an accurate drawing?

Also are the walls 2x4 or 2x6?

Load Bearing?

Just for my piece of mind we are not talking a firestop wall are we? Highly unlikely but I got to ask....:D

[Shaun Wesley]

Correct. Only difference is the main is on the right and sub on left. The garage is a 2 car garage with 2x4's. Only 1 side of the garage shares a wall with the house. The wall the panel/s are on is on an outside wall so it is load bearing. Clear as mud?

[Roger Frazee]

Does the service entrance to the 200 amp panel enter from the top or where does it enter?

Are most of the branch circuits entering the 200 amp panel from the top?

Do you have room on the top left side of the 200 amp panel and is there a knockout that will allow a 1 1/4 conduit? ...usually one is located there...it likely is a concentric knockout that will allow different sizes of conduit depending on which ring you remove.

If the above doesn't workout what is available on the bottom of the 200 amp panel?

[Shaun Wesley]

The main service entrance comes in from the bottom of the panel. The panel is 40 slots and is full with the 100 amp breaker for the sub. The best spot for the fiting is in the lower left side corner of the main panel. There is the concentric circles you were referring to there. It is big enough for a 1 1/4 pvc conduit. Can the conduit just rest in the main panel or does a bushing or nipple have to be connected. Because the conduit would go through the stud an even bigger hole would have to be made if a nipple or bushing would need to be used.

Edit:
I picked up a J shaped (not exactly a j but you understand) conduit and had envisioned the J connected to the sub and then entering the lower left side (through the stud) of the main panel.

[Roger Frazee]

Shaun I'm going to post another diagram to see if I understand your description give me a few minutes.

[Roger Frazee]

Door #1 or Door #2 ?

[Shaun Wesley]

Door #1!



Edit:
Wish I could draw that quick...

[Roger Frazee]

Ok that's fine. What I'd like to do if it is ok is ask a few questions then after you answer give me about 30 to 45 minutes to get images posted of the fittings you will need. And yes you are going to need a nipple. A box connector will cause too big of a hole and you will exceed the 40% allowed unless you can double the stud.

Did they locate the mains at the top of the 200 amp panel or the bottom?

I'm asking this only so we can be politically correct (if you want) on the sub panel mains. In other words most panels mains can be either up or down by rotating the panel.

Have you mounted the sub yet? I'm asking because we need to have it mounted high enough to allow the fittings to work. There should be a good difference in overall height between the panels like the diagram shows . I think you see where I'm going.

What brand of sub panel? If you haven't purchased it yet that is fine.

[Shaun Wesley]

Ok that's fine. What I'd like to do if it is ok is ask a few questions then after you answer give me about 30 to 45 minutes to get images posted of the fittings you will need. And yes you are going to need a nipple. A box connector will cause too big of a hole and you will exceed the 40% allowed unless you can double the stud.

Did they locate the mains at the top of the 200 amp panel or the bottom?

Bottom

I'm asking this only so we can be politically correct (if you want) on the sub panel mains. In other words most panels mains can be either up or down by rotating the panel.

Have you mounted the sub yet? I'm asking because we need to have it mounted high enough to allow the fittings to work. There should be a good difference in overall height between the panels like the diagram shows . I think you see where I'm going.

I have already mounted it but I can adjust it if need be. The Sub is mounted with the top about 2 inches below the main top leaving a large difference between the bottom of the sub and bottom of the main.

What brand of sub panel? If you haven't purchased it yet that is
fine.

Square D QO 125 amp panel with 20 spaces (Main Lug)

[Roger Frazee]

Ok you decide how you want your mains but I would leave the sub the way it is personally. Main lug was a good choice. Qo was an even better choice...:)

For a heads up be very careful drilling out the stud a hole saw 1 3/4" should be good. Whatever you choose be careful of the mains they are hot unless your have a remote disconnect to get power off them. Remove the wood and get that knockout out. Use a screw driver or punch then once you break it loose at the right ring move it so you can get a pair of pliers on it a work it back and forth till it breaks out. Do this after you remove the wood. they knock out from outside to inside of the panel. This is tricky on concentrics but if you break out the bigger ring there is an easier fix. Maybe 1 1/4 will be the outside ring...:). Take good measurments to get the hole correct.

Ok here is what you need building from the service panel to the sub-panel.

Nipple... get one long enough threaded both ends
and a couple locknuts for each panel to secure the conduit. 2 insulating bushings one for each end of the conduit run.

http://tbn2.google.com/images?q=tbn:JCvONvlfKd07nM:http://www.plumbingproducts.com/images/pvcnippleslarge.jpghttp://tbn3.google.com/images?q=tbn:Mdon6_vd0lc-uM:http://www.drillspot.com/pimages/386/38687_300.jpghttp://tbn2.google.com/images?q=tbn:Iq1i_rPKQeWzfM:http://images.hardwareandtools.com/P/6315758.jpg
Now once you have the nipple and it's long enough cut the threads off one end and get a glue on coupler like this.......then a non bell 90 degree sweep and glue a box connector on the end of the sweep

http://tbn3.google.com/images?q=tbn:gh2rgGNFJ7FsaM:http://www.foxelectricsupply.com/Content/Media/Images/Category/e940e.jpghttps://www.centralvacuumstores.com/images/sm/cvs/electric_90_sweep.jpghttp://tbn3.google.com/images?q=tbn:EBlzmX5Y97TrbM:http://www.stevesdebris.com/images/carlonE943EThumb.jpg

I think you can see how this all goes together. You may need some short length of straight pvc but I think you got that covered. Just remember measure twice cut once....:) If the sweep doesn't reach then you will need a short piece of pvc another coupler or a bell sweep will work. Then the box connector will go on last. Locknut and bushing.

Bell sweep with box connector glued on http://tbn2.google.com/images?q=tbn:xe4ikLbaAbFRFM:http://www.kissingfrogs.tv/lilypot6.jpg

Be sure to use the gray pvc not the white stuff. the threaded nipple will be schedule 80 located in a different area usually at the box store . The glue is with the fittings.

All of this is easy to find

Also remember your neutral and ground will be isolated at the sub panel. If you do not know what that means post back. But on square d you will not install the green screw bonding jumper and you will add a ground bar kit to the panel. Any questions start anohter thread about it and we will give you the instructions.

Hope this helps

[Shaun Wesley]

Sounds good Ill pick up that stuff tomorrow. Another few questions.
At the Borg all they had was black insulated THHN. Can I just tape the neutral and ground their appropriate colors and still be within code?

Lastly in a previous post you mentioned the size of the hole in a load bearing stud. Well in the lower portion of one of these studs the builder made about a 1 3/4 hole to fish abunch of wiring through to go inside the house. That equals 50% on a load bearing wall. Will I get hemmed for this on an inspection (maybe they just missed it the first go around) or is it that big of deal? I cant reinforce that stud or otherwise I would have to move the sub or main so that are further apart, but I can reinforce the studs on the opposite sides of the sub and main. (Im referring to the one in the middle of the two near the bottom is where the hole is).

Thanks for all the insight! I do appreciate you taking the time to help.

[Rollie Meyers]

Can the conduit just rest in the main panel or does a bushing or nipple have to be connected. Because the conduit would go through the stud an even bigger hole would have to be made if a nipple or bushing would need to be used.

Edit

Proper fittings are required. A terminal adapter (male adapter) /locknut/ and bushing are required, and PVC water pipe fittings & pipe are also not acceptable.:D

[Roger Frazee]

Sounds good Ill pick up that stuff tomorrow. Another few questions.
At the Borg all they had was black insulated THHN. Can I just tape the neutral and ground their appropriate colors and still be within code?

Lastly in a previous post you mentioned the size of the hole in a load bearing stud. Well in the lower portion of one of these studs the builder made about a 1 3/4 hole to fish abunch of wiring through to go inside the house. That equals 50% on a load bearing wall. Will I get hemmed for this on an inspection (maybe they just missed it the first go around) or is it that big of deal? I cant reinforce that stud or otherwise I would have to move the sub or main so that are further apart, but I can reinforce the studs on the opposite sides of the sub and main. (Im referring to the one in the middle of the two near the bottom is where the hole is).

Thanks for all the insight! I do appreciate you taking the time to help.

Sorry Shaun had to step out for a bit.

The critical part of this is going to be the close distances involved and the distance B in the drawing below.. I don't know what that is because I don't know the height of the panels. If the sweep doesn't work and it looks ok to you move the sub-panel down and come into it through the side just like your service panel in which case all you will need is a nipple locknuts and bushings. Sorry for the change of direction to consider but I don't know the distance B and your knockout pattern.

I wanted to say you can enter the sub from the bottom anywhere you want that the knockout is big enough. The diagram may not necessarily be where you want to enter it just depends on the knockout pattern your given. You will not be able to enter on the right though because it won't work out ....not enough lateral distance. You want to avoid sharp 90 turns like 90 elbows.

The ground by code since it is 6 awg should be green insulated. If it was one more size larger (#4 or bigger) you could tape it green at the terminations. An inspector may let you slide though on that , they do quite often and your ground is one size larger than it needs to be.

Tape your neutral white. You can if you want identify one of your ungrounded hot wires red but it isn't required.

I don't think you have to worry about the hole being 1 3/4 I see this all the time and it passes inspections. I'd just let it go. What I would do though is put a nail plate on the face of the stud so a screw or nail can't
penetrate the wires when the sheetrock goes on. Looks like....

http://tbn1.google.com/images?q=tbn:MGU9X9iPdYChNM:http://images.orgill.com/200x200/9620386.jpg


Doubling the outside studs is fine but not required...I probably would if it were me.

All your going to need is a sweep, coupler and nipple the right length to line up with the center knockout... then it will be just a matter of whether the sweep with box connector is long enough to enter the sub-panel. It will look something like this below....only variable will be your height to the sub panel. You can cut some off the sweep if needed or add a coupler and length of pipe then the box connector. Remember you can move the sub some if needed.

I just realized I made an error earlier the hole size is 1 3/4" for 1 1/4" PVC. I think you will be fine with that. May want a nail plate as well. My experience is that when the hole is between 40% and 60% and your only boring one stud on a load bearer wall they will pass it. Sounds like you will have two in that stud but I've seen this ok'd... can't bet the bank on it though. So you might want to check before you drill. Unless you can double it somehow but that will require some work in order to fit the sub-panel.

Also Square d panels that flush mount have a pretty good trim lip so the panel covers are going to be very close to touching on the middle stud. So just a heads up. Also if distance B does not allow the sweep to work you can consider an LB fitting like this..... the knockout pattern if center doesn't work will determine your choices http://tbn2.google.com/images?q=tbn:pI0SuT831Npc2M:http://www.mclendons.com/img/products/10/10214970.jpg