Adding 2nd sub panel below existing one.

[Jmanb13]

My garage shop is expanding and I want to add a subpanel to cover all the 240v tools I currently have and will have in the near future.

I have a question about if code permits adding 2 subpanels over/under each other. I've tried searching but its a somewhat unique question and I haven't found anything on it.

Below is a picture of the current setup. I want to shift the current sub panel up on the wall and install a 2nd panel below it. The new panel will house all of the 240v circuits for my larger tools (air compressor, welder, lathe, table saw, etc).

The red boxes represent where I want to have the panels located. Each panel will be run off its own separate 100amp feed from the main panel (represented by the red line) The existing breaker in that space is the current wall receptacles for the garage and will be relocated to the new sub panel.

Side question: WTF is the blue corrugated tube on the existing sub panel? Its totally empty and goes up and over into the same stud space as the main panel, but there is nothing inside the actual tube.

 

[BillK]

Instead of doing that why not just get a larger subpanel and swap your existing breakers into it ? That would be a lot neater and probably not very much more expensive than your plan.

 

[mike93lx]

why use two subpanels? just install a single larger with a single 100a feeder. what benefit do you think you are getting with a second one?

any question including code has to include your location for anyone to be helpful. we don't know if you are in kansas, alberta or south africa

 

[Jmanb13]

I'm in Norman Oklahoma.

My main thought for the 2nd panel was because of the loads that are currently in it and may be in it in the near future. I know that certain tools are only going to be operated one at a time, but with what I plan to put in the sub panel plus what is already in there I could conceivably see it being more than the 100 amps. It would be rare but possible. Electric Garage Heater + Compressor + Plasma Cutter could easily be running at the same time and that doesn't include the other couple circuits that are already connected that includes lighting and some appliances from the kitchen such as the refrigerator and microwave that are already on that panel.

Edit: I just had a thought. I could easily move my Electric heater to the main panel and that should easily cut down on any over currents on the sub panel that might occur when running the heater plus tools. I can not conceivably think of a situation where a combination of tools used together could put too much current for a 100 amp sub panel as long as my electric heater is not on that panel as well.

 

[PCustoms]

You've got me confused by that last post....

But hell, run a single 200A sub in that spot if it makes you feel good.

Not going to make a bit of difference if you run 100A and 100A on subs, 200A on a single sub, or move a load to the main. you are still going back to the same main.

 

[Jmanb13]

You've got me confused by that last post....

But hell, run a single 200A sub in that spot if it makes you feel good.

Not going to make a bit of difference if you run 100A and 100A on subs, 200A on a single sub, or move a load to the main. you are still going back to the same main.

My only reason for not doing a bigger sub panel with more spaces in the first place was because of possible load on the sub panel. My electric heater + compressor + plasma cutter (all could be running at same time) all on the same sub panel would be right @ 100 amps. If any of the other small appliances that was on that panel was used at the same time (like the refrigerator, hot water heater, microwave, etc) it would trip the breaker for the sub panel.

If I move the electric heater to the main panel, that moves a possible simultaneous load of ~25 amps from the sub panel to the main panel. This would allow me to hook up all my 220v tools to the larger (more breakers) sub panel and since i would never be using multiple tools at the same time the panel would be fine feeding all of those together.

Basically i'm taking the advice from before of just getting a bigger subpanel with more spaces instead of adding another subpanel

 

[Jim greengo]

Instead of doing that why not just get a larger subpanel and swap your existing breakers into it ? That would be a lot neater and probably not very much more expensive than your plan.

 

[Jmanb13]

Thanks for the assistance! Went ahead and ordered a 24 slot sub panel. Should work out really well

 

[wyliesdiesels]

My only reason for not doing a bigger sub panel with more spaces in the first place was because of possible load on the sub panel. My electric heater + compressor + plasma cutter (all could be running at same time) all on the same sub panel would be right @ 100 amps. If any of the other small appliances that was on that panel was used at the same time (like the refrigerator, hot water heater, microwave, etc) it would trip the breaker for the sub panel.

If I move the electric heater to the main panel, that moves a possible simultaneous load of ~25 amps from the sub panel to the main panel. This would allow me to hook up all my 220v tools to the larger (more breakers) sub panel and since i would never be using multiple tools at the same time the panel would be fine feeding all of those together.

Basically i'm taking the advice from before of just getting a bigger subpanel with more spaces instead of adding another subpanel

What is the HP rating on the compressor?

What make and model plasma cutter do you have?

What is the KW rating on the heater?

 

[walrus]

The blue **** is conduit, commonly known as smurf tube. Probably put in so circuits could be added once walls were closed in.

 

[mike93lx]

while you are in there and moving stuff around, it would be a good time to add a whole home surge protector.

 

[larry4406]

I was thinking it would be a good time to install a new panel that has a built in manual transfer switch for a generator. Put your home essential loads in that panel then your sacrificial loads in the existing panel.

 

[mike93lx]

I was thinking it would be a good time to install a new panel that has a built in manual transfer switch for a generator. Put your home essential loads in that panel then your sacrificial loads in the existing panel.

Why not just an interlock in the main allowing you to light up any circuit in either panel? A lot cheaper too

 

[larry4406]

Why not just an interlock in the main allowing you to light up any circuit in either panel? A lot cheaper too

Agreed - some folks however get their ******* in a wad with that solution.

 

[mm08822]

Thanks for the assistance! Went ahead and ordered a 24 slot sub panel. Should work out really well

Your sub panel already has 12 ckt used. For all the effort of changing out the panel make it at least 30.

 

[Jmanb13]

The blue **** is conduit, commonly known as smurf tube. Probably put in so circuits could be added once walls were closed in.

I might have to run a snake up through the tube to see if I can figure out where it goes.

while you are in there and moving stuff around, it would be a good time to add a whole home surge protector.

Good call!

Your sub panel already has 12 ckt used. For all the effort of changing out the panel make it at least 30.

Both my panels are EATON BR panels. Figured to save cost I would stay with that style to be able to re-use my breakers. The 24 space was the biggest I found that wasn't a full main breaker panel. I guess could just use a 2nd main as the sub. That one is only $20 more than the 24 space panel.

Something like this https://www.lowes.com/pd/Eaton-Type...-Main-Breaker-Load-Center-Value-Pack/50343442
or this.
https://www.lowes.com/pd/Eaton-Br-6...-On-Neutral-Load-Center-Value-Pack/1000551293

What is the HP rating on the compressor?

What make and model plasma cutter do you have?

What is the KW rating on the heater?

5HP
Everlast PowerPlasma 80s
6000w
Plus almost every appliance and circuit from my kitchen

The heater runs quite a bit during the winter so its pretty much guaranteed it will be running whenever I'm using other tools.

 

[mike93lx]

I would put in the biggest panel that is reasonably priced. This isn't something you ever want to have to replace

 

[Jmanb13]

Thanks to all the suggestions I went ahead with a 200 amp, 30 space - 60 circuit main panel. Will be 100 amp feed from main panel and the 200 amp breaker will just be a disconnect.

If in the future I need more amperage it will just be a matter of moving to a feed through/sub feed lug setup with a wire upgrade instead of an entire panel replacement.

BRP30B200V25 - https://www.homedepot.com/p/Eaton-BR-200-Amp-60-Circuit-Main-Breaker-Indoor-Plug-On-Neutral-Load-Center-Contractor-Kit-2-BR120-and-1-BR230-BRP30B200V25/306343443

 

[mike93lx]

Great choice

 

[Jmanb13]

Got the box replaced and most of it buttoned up. All I have left is to mark the white wire as hot (couldn't find my electric tape), move my garage circuit to this box, and add a surge protector to the main box.

I might go ahead and have a electrician come out and run a sub feed to the 2nd box so I have the full 200amps possible. Gives me the bonus of having the proper permit pulled and the metal box blessed by the guy with the badge.

 

[wyliesdiesels]

FYI- the bars on the plastic risers/insulators are meant for neutrals and you add ground bars on each side. This makes for a neater panel since wires dont have to cross from side to side.

 

[Jmanb13]

FYI- the bars on the plastic risers/insulators are meant for neutrals and you add ground bars on each side. This makes for a neater panel since wires dont have to cross from side to side.

Ahh so your saying leave the bonding strap between the 2 top sets and run them both as neutral then add additional ground bars to the bottom left/right spots that are blank? The old panel that I replaced was setup just like I currently have it setup so I configured it the same.

I removed the bonding strap and grounded the bar on the right with the included grounding lug that was originally turned 90* and unattached.

I haven't researched sub-feed setup enough yet, but would the bonding strap have to be re-installed if I got the full service to the 2nd panel?

 

[Fasthotrod]

Howdy, neighbor.

I believe what he was saying was to leave the two isolated neutral bars connected so you can keep the various wiring bundles together (left and right sides) but remove that grounding tab that's connecting the can to the bar about half way down on the right hand bar. Then run over to your local electric supply house and pick up some separate ground bars that screw directly into the can towards the bottom. That keeps everything looking clean and organized.

I'd bet that Locke Supply at 1500 24th Avenue SW head exactly what you need. (I bought some there for a project in the past. They aren't expensive.)

I cropped your picture so that you could see the grounding point that needs to be removed if you keep the two existing bars as isolated neutrals and install separate ground bars.

Hope this helps.

Mark

 

[Fasthotrod]

One more thing... rather than try and get another service feed to that panel, you might want to just increase the size of the feeder from the main to the sub panel. If you could relocate/move two loads from your main panel, you could remove that 100A breaker and install a sub feed block instead. I did it in my Square D panel, and they make one for the Eaton BR series as well. More info here:

https://www.garagejournal.com/forum/showpost.php?p=7663364&postcount=35

Taken from this thread:

https://www.garagejournal.com/forum/showthread.php?t=410968

 

[Jmanb13]

Howdy, neighbor.

I believe what he was saying was to leave the two isolated neutral bars connected so you can keep the various wiring bundles together (left and right sides) but remove that grounding tab that's connecting the can to the bar about half way down on the right hand bar. Then run over to your local electric supply house and pick up some separate ground bars that screw directly into the can towards the bottom. That keeps everything looking clean and organized.

I'd bet that Locke Supply at 1500 24th Avenue SW head exactly what you need. (I bought some there for a project in the past. They aren't expensive.)

I cropped your picture so that you could see the grounding point that needs to be removed if you keep the two existing bars as isolated neutrals and install separate ground bars.

Hope this helps.

Mark

I think we are saying the same thing. Convert it back to its factory setup with the 2 top bus bars connected together with the strap, and the grounding tab NOT connected. Then add additional ground bars in the blank spaces at the lower left and lower right of the box. That way wires coming in the left side all stay on the left, and wires coming in the right side all stay on the right.

Thinking about wire routing of ground and neutral on the same side in the sub panel how would I route the ground wires to the bottom on the same side as the neutral without the ground having the possibility of accidentally touching the neutral bar? Just run it down the same channel where the hot wires are?

One more thing... rather than try and get another service feed to that panel, you might want to just increase the size of the feeder from the main to the sub panel. If you could relocate/move two loads from your main panel, you could remove that 100A breaker and install a sub feed block instead. I did it in my Square D panel, and they make one for the Eaton BR series as well. More info here:

https://www.garagejournal.com/forum/showpost.php?p=7663364&postcount=35

Taken from this thread:

https://www.garagejournal.com/forum/showthread.php?t=410968

That is good info and what I was looking at doing! Using the BRS225 to run power to the 2nd box.

From my research looking at the NEC, It looks like I would need 2/0 Copper for Hot/Hot/Neutral and a #1 ground to support the 200 amp to the sub panel?

Since these panels are right next to each other it seems the easiest way to connect them with a feeder would be to just bore a hole from 1 panel to the other and run the feed through them. My 2x6 load bearing stud @ max 40% hole size would allow up to 2.2" hole. This would allow either a 1.5" or 2" metal conduit ****** between the 2 panels. A BRS225 + a couple feet of THHN and everything would be hooked up.

Thoughts?

Pic for reference as to what I'm thinking. Could be adjusted for the before mentioned ground and neutral setup by moving the grounds to the bottom of panel.

 

[Jmanb13]

I've read that fill capacity for a ****** (conduit shorter than 24") is 60% instead of 40% for normal conduit. Based on online calculators, that means I could use a 1.5" x 3" EMT ****** connecting the 2 boxes and then put (3) 2/0 + (1) #1 ground through that and only be at 40.1%. Heck a 1.25" conduit is still only at a fill capacity of 55% and is easier on the load bearing stud. If the ground isn't considered a "current" carrying conductor then my (3) 2/0 would be under the 40% rule on a 1.5" conduit regardless.


Are my calculations correct?

My boxes actually have knockouts exactly aligned at the top that I could take out and put the ****** through it.