Mounting the breaker panel

[Knight511]

Here we go with my first thread to get roasted in... please forgive me because I am a 6th grade science teacher who has just finished the gauntlet of state testing with the kids, so I am finally able to day-dream and plan stuff again.

Hopefully a simple question. I live outside city limits in Johnson County, Texas. I am finishing out my workshop and have been planning the interior electrical (the hook up to the main panel will be done by a pro). This seems like a simple question, but my mind won't settle.

Does a panel have to be mounted to a piece of wood? My shop is metal tube framed and will use metal girts to secure sanded (not SMOOTH) T1-11 for the walls. Once the T1-11 is mounted to the girt, can I just screw the panel to the T1-11 and call it done? Should I raise it off the wood using some strut channel (like I am using for conduit across the ceiling)?

The panel will be surface mounted with exposed conduit from the panel across the ceiling. The conduit will be hidden behind the walls in every other part of the shop. I would like to get the panel mounted to start bending the offsets for the first lengths out of the box before I get the scissor lift to finish the rest of the work in the shop.

Most of what I am doing would be overkill and has already been roasted else where as far as wire gauge in the shop, so I will spare those details. I have been learning and practicing bending conduit, and I have been really loving learning everything I have been about running the electrical.

Thanks in advance.

 

[zeke67]

You can mount it to the T-11.

 

[wyliesdiesels]

no code requirement for plywood mounting. just makes for a nice mounting surface

 

[Innovate1]

Others may correct me but I believe the only requirement is that it be physically supported (not supported by the conduits) and the front area must be open for access. It could be attached to metal, wood, concrete, plastic, etc. Oh, and there are also height requirements.

 

[rlitman]

...The panel will be surface mounted with exposed conduit from the panel across the ceiling...

The panel just needs to be solidly mounted. Directly attaching to the T1-11 is fine, and you'll have larger conduit offsets if you raise the panel on channel, so why add the complexity?

If it were me, I'd put a large wire trough at ceiling height directly above the panel, with a way oversized pair of conduits connecting that to the panel. Then, you can distribute your conduit out of the trough, and use that as a pull box, keeping the wall above the panel cleaner.

 

[dcg9381]

I'm in Texas, I've never seen or heard of a panel mounting violation (doesn't mean it can't happen).

I have a building like yours, I did a wood offset rather than go straight into the gurts. If you're concerned (at all) put some 2x4s on the back side of that t-111 and secure into it from the sides of the panel.

My shop is done in 4x8 OSB on top of 2x4 framing. If I need to rewire something, I can pull one panel off at a time to get "behind" the wall.


Absolutely secure that panel in an appropriate manner.

 

[u2slow]

If this is being inspected, you should know some jurisdictions now require fire-resistant-treated plywood.

I have used regular plywood in my place so far.

 

[Knight511]

I have a building like yours, I did a wood offset rather than go straight into the gurts. If you're concerned (at all) put some 2x4s on the back side of that t-111 and secure into it from the sides of the panel.

I am actually using a metal "stud" as the horizontal gurts. Those will be screwed directly to the metal tube frame to make installing the T1-11 easier. I am avoiding 2x4s due to the cost of wood right now; it is actually cheaper to use the metal instead.

These are the "studs" (they aren't really stud shaped to me): https://www.lowes.com/pd/3-2187-in-W-x-120-in-L-x-0-875-in-D-Galvanized-Steel-Stud/3370386

 

[Knight511]

..................................

 

[Knight511]

The panel just needs to be solidly mounted. Directly attaching to the T1-11 is fine, and you'll have larger conduit offsets if you raise the panel on channel, so why add the complexity?

If it were me, I'd put a large wire trough at ceiling height directly above the panel, with a way oversized pair of conduits connecting that to the panel. Then, you can distribute your conduit out of the trough, and use that as a pull box, keeping the wall above the panel cleaner.

Whoa! I was worried about how large of conduit I would need for the shop, so I stuck in 2" to consider this option. I would only fill a single 2" to ~30% for all of the wiring that I currently have planed, so 2 2" would be ample room for any growth in the future.

Thanks for the idea, I am going to roll it around tomorrow while working on the shop.

 

[nadogail]

Leaving room for "Future Growth" is a good idea that is overlooked by many.

 

[rlitman]

Whoa! I was worried about how large of conduit I would need for the shop, so I stuck in 2" to consider this option. I would only fill a single 2" to ~30% for all of the wiring that I currently have planed, so 2 2" would be ample room for any growth in the future.

Thanks for the idea, I am going to roll it around tomorrow while working on the shop.

I know you asked for a picture (and I'd have taken some at the office if I saw your message in time, but unfortunately I did not), but it seems like you got it now. It's a common commercial practice. Put up a big wiring gutter above the raised ceiling, and a couple of mega pipes straight down from there to the panel.

2" sounds about right. Remember that you'd be doing a straight run up to the trough with them, so without any bends, the hardest part will be cutting out the holes for the knockouts (and now you don't need to bend every small conduit down the wall any more). Don't forget the protective bushings.

But also remember that 30% is kinda tight, because you'll want to be able to snake more wires in the future while they're already got wires in them. Conduit fill calculations assume you'll be pulling everything at once. Still, these will be short.

One VERY important detail if you do this. ALL conductors of a circuit MUST go through the same pipe with each other! Don't put all the hots in one and the neutrals in the other, because that can inductively heat the conduit.

Oh, and if the top of your panel is close enough to the trough, you could just connect the two with chase ******* instead of actual conduits.

 

[Knight511]

Leaving room for "Future Growth" is a good idea that is overlooked by many.

I have no choice but to think ahead. I only NEED 3 20amp circuits right now to be 100% great, but I know I want to add metal working tools, upgrade the motor on my table saw, add dust collection, and be able to park/charge an RV in the shop in the future. I have made due with a single 20amp cirtcuit for so long now... I know I have to turn the vacuum on, let it come up to speed, turn the table saw on, let it come up to speed, and then slow my feed rate if the saw starts to slow down.

I am running empty conduit to the places I think I will put the 240v plugs and using 1" emt (extra space and is the size needed to run 6g for the 240s). I am using 10g THHN (which I KNOW is too big, but I won't have voltage drop and won't have to buy multiple wires for 20 or 30 amp) for everything. I only have to buy 1 bender as a result.

I did make a mental change today though... I will add a dedicated ground wire (12g) for the 110v 20a circuits now instead of relying on the EMT for the ground. It may be redundant, but redundancy is only when it will only cost an extra $100 in wire.

I didn't touch the shop today though. I just needed a day off from everything. I will have a 19' scissor lift for 4 weeks in June to knock everything else out. That will make my life easier (and safer) than using scaffold or a step ladder or both. I am super excited since this shop, so I am sure I ramble a bit here.

 

[Knight511]

2" sounds about right. Remember that you'd be doing a straight run up to the trough with them, so without any bends, the hardest part will be cutting out the holes for the knockouts (and now you don't need to bend every small conduit down the wall any more). Don't forget the protective bushings.

I would run 2 2" conduits straight up, but there is no drop ceiling for my shop. It will just be open to the ceiling. Everything will be run across the ceiling above where there would be a true ceiling just in case I change my mind in the future.

One VERY important detail if you do this. ALL conductors of a circuit MUST go through the same pipe with each other! Don't put all the hots in one and the neutrals in the other, because that can inductively heat the conduit.

Segregating wire type didn't even cross my mind although I can see how some DIYers may think that is a good idea. I have done too much 12v work to not have all wires for a circuit together for future repairs and work.

Oh, and if the top of your panel is close enough to the trough, you could just connect the two with chase ******* instead of actual conduits.

The ceiling is 14' high, so I would not think a ****** would work. What are the requirement differences using a ****** vs a straight piece of conduit?

 

[Knight511]

I bet this will not work:

https://scontent-dfw5-2.**.fbcdn.net/v/t1.6435-9/139780419_10220026111069147_3013378908717868464_n.jpg?_nc_cat=108&ccb=1-3&_nc_sid=0debeb&_nc_ohc=JnE9idkRsk0AX9Uh6Wg&_nc_ht=scontent-dfw5-2.**&oh=fba096a21299aba81a59d8b7a5eebcfc&oe=60C74713