Main panel installation questions

[ishiboo]

I am installing a new 200A main panel, and have a couple questions. This is in a basement with a stone foundation, so I will be building a 2x4 wall in front of it and mounting a piece of 1/2" ply with moisture barrier to the backs.

1. My plan is to built a 4' wide wall, with a 24" center cavity for the load center and an area on each side to act as a wire chase so I can staple the wires and they will reach the ceiling. The panel will be mounted to the back of the plywood so in the future, a future wall can be drywalled and the panel will be recessed. What prevents this from being declared a raceway/conduit and being subject to derating/conduit fill? Can the top plate be "open" or must I have a top plate with many holes to get around this?

2. The panel is a 200A Homeline. There are ground bus bar locations on each side - is it okay to install both ground bars? I don't see this detail in the specs, but I believe it is.

3. The panel will be fed initially by 2-2-4 service entrance cable. I have 100A main breaker in an outdoor enclosure below the meter. In the future, I will be trenching electrical to the barn and the barn will supply power to the house. Is 2" conduit sufficient to account for this future (4/0 4/0 4/0 2/0 I assume) service? The conduit will enter the back of the panel (not the top) and I will need to make a turn via a LB to direct towards the ground. The bigger the conduit the worse it looks on the outside of the house, or I'd go 2.5".

4. Any best practices/forethoughts you have in a new panel installation?

I will have a 30A transfer breaker with the interlock kit initially, but in the future when the power is fed from the barn there will be an ATS there. I may need to add some load relays at the house but my plan is to put those, as well as things like a whole home surge protector, timers, etc. to the left and right cavities next to the panel.

This panel will feed an old 100A panel serving the 1st floor whose circuits will be gradually rerouted into the new panel (after removing the ground/neutral tie of course), as well as a new 100A QO panel on the second floor.

 

[Aceman]

1. My plan is to built a 4' wide wall, with a 24" center cavity for the load center and an area on each side to act as a wire chase so I can staple the wires and they will reach the ceiling. The panel will be mounted to the back of the plywood so in the future, a future wall can be drywalled and the panel will be recessed. What prevents this from being declared a raceway/conduit and being subject to derating/conduit fill? Can the top plate be "open" or must I have a top plate with many holes to get around this?

A stud cavity is not a raceway. Don't install a top plate unless you want to drill holes.

2. The panel is a 200A Homeline. There are ground bus bar locations on each side - is it okay to install both ground bars? I don't see this detail in the specs, but I believe it is.

Both grd bars are fine.

3. The panel will be fed initially by 2-2-4 service entrance cable. I have 100A main breaker in an outdoor enclosure below the meter. In the future, I will be trenching electrical to the barn and the barn will supply power to the house. Is 2" conduit sufficient to account for this future (4/0 4/0 4/0 2/0 I assume) service? The conduit will enter the back of the panel (not the top) and I will need to make a turn via a LB to direct towards the ground. The bigger the conduit the worse it looks on the outside of the house, or I'd go 2.5".

Your lugs most likely aren't rated for #2. Change the lugs or upsize the SE cable. Or convince the inspector it's only temporary and leave it as is, I'm sure the lugs will tighten down on the wire fine, it just won't technically be legal.

I'd strongly recommend 2.5". I'll give you an example, I fed a mobil home with 2" pvc about 70' long. With one 90 and two 45's it took a come-a-long to finish the pull. On top of that, I highly doubt a 2" pvc LB can handle that cable, so at the bare minimum you'd be using a 2.5/3" LB with reducers to fit 2" pvc. You'd have to look inside the LB to see for sure what it can take.

4. Any best practices/forethoughts you have in a new panel installation?

Run two 12/14-2 through each connector. The same for stapling, stack one on top of the other when stapling to save space. Use stackers where space is tight or where it's hard to staple.

http://www.idealindustries.com/prodDetail.do?prodId=BPSTCKR-15&div=4&l1=cable_staples

Try to not cross your wires too much in the panel. I'll see guys make a total mess, they'll bring cables into the top of the panel and run them to the bottom to hit a breaker and vice versa. It can turn into a wreck quick, especially in bigger panels. Some people can make anything look good though, but it's easier to bring your cables into the end/side closest to the breaker if at all possible.

This panel will feed an old 100A panel serving the 1st floor whose circuits will be gradually rerouted into the new panel (after removing the ground/neutral tie of course), as well as a new 100A QO panel on the second floor.

Why mix Homeline and QO panels on a new install?

 

[Charles (in GA)]

With a disconnect on the outside at the meter, you will need to supply this panel with four wires, two hots, a neutral, and a ground, (2-2-2-4) and not three wire.

Schneider/Square D Load Center catalog page 40/56 and on shows all 200 amp main panels being approved to accept either #4 or in some cases #6 as the smallest size and 250 kcmil as the largest. The placard on the inside of the door will give you the information you need to prove to the inspector that the wire sizes you have used are acceptable for the panel.

Charles

 

[Aceman]

With a disconnect on the outside at the meter, you will need to supply this panel with four wires, two hots, a neutral, and a ground, (2-2-2-4) and not three wire.

Oops, missed the outside disconnect, good thing Charles is paying attention!

 

[wyliesdiesels]

Good eye! I was gonna comment about the 3 wire feed but Charles beat me to it.

 

[joe_padavano]

So this is technically a sub-panel. The second ground bar is actually the bonded ground for the fourth wire (the 4 gauge). The first ground bar is the neutral that connects to the white 2 gauge. You do NOT want to bond this neutral to the box.

 

[wyliesdiesels]

So this is technically a sub-panel. The second ground bar is actually the bonded ground for the fourth wire (the 4 gauge). The first ground bar is the neutral that connects to the white 2 gauge. You do NOT want to bond this neutral to the box.

And therefore would be called a neutral bar NOT a ground bar!

 

[ishiboo]

Thanks folks. I know the ground/neutral should be bonded in the disconnect or meter can and move forward separately, but I'm going to be cheating on this a bit. It's not a significant issue, other than it being the only part that won't pass. Reason being is the disconnect was installed in the service entrance cable that existed, which did not go directly to the main panel but ran around the house 25' and then into the house 20' before reaching the panel, with no overcurrent protection. So, I made things better - but could not correct the ground to code without a much bigger project.

Once spring hits I'll take the mini-ex and run 4 conductors from the new main panel in the barn and all will be well.

Great tips/info on all the rest. Reason for QO vs Homeline is simply cost and size - we know the Homeline breakers have the same safety margin/reliability and far lower breaker costs, but the QO allowed me to get a small panel where it had to go in an area where the visi trip indicators would come in handy during an outage. Plus it is an 8-space QO panel, and a 40-space Homeline... costs of filling the Homeline which could be quite full would be very high