Hello all... I've been reading on this site for several days and have spent many, many hours trying to catch up on all the codes. I am in the process of finishing my basement and am wiring it myself. I have worked with wiring all sorts of things my whole life pretty much so I am familiar with most of what I should do. I do have a few questions though that I could not find in searches. Most of the electrical work that I have done has been limited to installing a new breaker for an added appliance or wiring my workshop, etc. Now I need to add a sub panel and need a few questions answered.

I presently have a 200 amp service and all the spaces are filled. So... I need to add a sub panel. The guy at Home Depot said there were several ways to do it. I could add another main breaker box with its own main breaker and cutoff or add a sub panel and add a breaker to extend power to the sub panel. I opted for “Bigger is better” and bought the main breaker box. (Square D HOMVP5) It’s just as big as the one I have now but rated at 100 amps instead of 200 amps like the one that came in my house. It also has a main breaker. From what I have been reading… This is overkill and all I really need is a sub panel. I understand that I need to isolate the ground and why. So… Now for my questions…

1. Should I stick with what I’ve got or return it and get a smaller sub panel?

2. I plan on mounting it under the main breaker box. Is there any code that says how high it must be from the floor? I’ve searched for days and couldn’t find an answer.

3. Can I use the same thick copper ground grounding rod for the sub panel as the main panel?

4. If I use the sub panel I’ll need to move a breaker down to the sub panel… But the wires won’t be long enough to extend for the breaker I take out. Can I just use wire nuts inside the main panel to wire in an extension to the new sub panel?

5. I have several pull string lights in the basement. I’d like to just wire nut the connections inside a junction box and seal them in the ceiling. I’ve read that these need to be accessible. What’s the scoop on that? Once they are safely contained can I just seal them up in the ceiling with drywall?

6. I have already roughed in the wiring for my outlets using 14-2. Should I take that out and use 12-2? I’ll split them into separate circuits… The most on one circuit would be 7 outlets.

I’ll appreciate anyone’s input.

Thanks in advance!

Rick

 

1.Return the main & get a sub-panel, And dont belive all of the H.D guys advice especially with service equipment
2.The height of the working space as defined in Art.110.26{3} of the NEC The work space shall be clear & extend from the grade,floor or platform to the height of 6 1/2'.
3. You may have to drive another rod, I'll have to look that one up.
4.I recommend pulling the wires out of the existing panel & making a splice above the sub
5.The J.B s for the pull lites must be accesible, no exceptions
6.I'd run 2 circuits for the receptacles 15 amp is fine
The local inspector has authority over & above what the NEC says, you'll want to consult them

 

1. Up to you. You can easily make what you have work.
2. No minimum. Under the main panel is fine.
3. The subpanel must not have its own grounding rod. The grounding wire between panels is the only grounding necessary and the only one allowed. Do not add a grounding rod not make any new connection to existing grounding rods or plumbing pipes.
4. Yes, if you are in the United States.
5. They must remain permanently accessible. Under no conditions can you seal up boxes containing live or potentially live wires. However, if you can disconnect and cut off the cable at the box they come from, and if the box they come from remains accessible, then you can abandon the box that contains wires that cannot possibly become energized. Or just use that circuit to power a few lights in your newly finished basement. Or maybe reroute the cables into an unfinished section of the basement. Or...there are lots of possible solutions.
6. I would have used 12/2 in the first place. But if the 14/2 is already there, I don't think I'd remove it. Add more circuits if you need more power.

 

Okay... I have all the stuff but I am a little confused. I have included a link to a picture I took of the subpanel I purchased. I have some text on the photo that asks some questions. Sorry for the size of the picture but I wanted to display all the detail.

HERE'S THE LINK

In all the pictures and drawings I've seen, it shows the neutral and ground bars isolated... And you may connect them (if needed) with the bonding screw. I know I DO NOT want to do this... However, there is a bar that looks like it is connecting the two that should not be there. You'll see the detail in the picture.

There is an additional bar that says it should be used to bong the two rails... I throw this away, correct?

Also... In the picture... I'll need to put the neutral terminal on the neutral bar so I can connect the #2 aluminum wire I purchased, correct? (Right hand side of picture.)

I guess I'm confused about the bonding because the two already look like they are connected. Any insight would be greatly appreciated! I'd like to mount this tonight and get started... Or return it and get a correct subpanel.

Thanks everyone!

 

The neutral bars are floating
The Ground bus is not floating
the panels I used, I had to buy a grounding buss bar and screw it to the box using the two pre drilled holes to the left of your breakers in your picture.

maybe that bonding screw makes that bar the ground buss.
Read the instructions.

 

Whenever you are wondering if two things that "look like" they are connected really are connected, it's time to get out the ohmmeter.

Don't throw away the grounding bar. Install it. You need it. That's for your grounding wires. The two bars already installed are for your neutrals and those two bars should be connected.

But yes, do throw away that green screw.

And yes, put the lug on the neutral bar.

 

They say that knowledge is gained by reading the instructions....

Experience is gained by NOT reading the instructions... Heh heh...

I snapped another picture... I finally figured it out. It just didn;t look the same as in the books I have and on some of the stuff I've seen on the net...

Here's The Corrected Photo Link

I did read the instructions but not the ones included with the ground bar... NOW it all makes sense and looks like it should...

Thanks for everyone's help!

 

Post # 4
"Also... In the picture... I'll need to put the neutral terminal on the neutral bar so I can connect the #2 aluminum wire I purchased, correct? (Right hand side of picture.)"


Don't use aluminum wire, use copper.

After seeing the link below, I cant say what size wire to use with a 100 amp breaker. by the book.
Maybe John N. can post the size wire needed.

http://forum.doityourself.com/showth...2&page=1&pp=40
------------------------------------------------------------
I don't know if its a code.
We always position the largest breakers closest to the power input lines that feed the power rails for the breakers.
In any panel.
May prevent your lights from dimming if your sub panel has a large load.
------------------------------------------------------------

Be sure to have all power wires (2-hots 1-neutral 1-gnd (the big wires)) feeding your new sub-panel thru the same pipe/hole
You don't want to create induction heating by going thru separate holes.
--------------------------------------------------------

 

There was a post I saw in my research here (And I think John was a part of it) that said the proper wiring for a 100 amp service panel was either #2 aluminum wire or #3 copper. Nobody has #3 copper around here. No specialty stores... Nothing. In talking with others... and reading up on the subject... #2 aluminum is pretty much the standard.

"Be sure to have all power wires (2-hots 1-neutral 1-gnd (the big wires) feeding your new sub-panel thru the same pipe/hole
You don't want to create induction heating by going thru separate holes."

Thanks for the input but I would think this is a "no brainer"... the cable I bought is #2 aluminum Type SER that has two hots, a neutral and a ground. The whole thing is sheathed in some pretty thick plastic sheathing.

Does anyone else see it as a mistake using #2 aluminum for a 100 amp subpanel?

 

#2 is standard for 100 amp services I have used AL cable for years & never had a problem.Make sure you use antioxidant & check the tightness of the connections before you wrap-up the job.

 

Okay... I got it all in and it works like a CHAMP! Thanks to all who helped me make the correct decisions. I wired all the lights and dropped two circuits down to make room for the 100 amp breaker. I'll add more circuits as I finish off the rest of the basement. The compressor and a few spare lines for future expansion will be added tomorrow... As well as the bathroom. I'll post back as I finish more.

Thanks again!