100amp Basement Subpanel

Reply

  #1  
Old 11-13-13, 09:57 AM
Member
Thread Starter
Join Date: Nov 2013
Location: USA
Posts: 6
100amp Basement Subpanel

This is my first post here, but I have been lurking around these forums for quite awhile now and have always found them a useful source of info.

I pulled a permit and installed a 100amp subpanel in my basement about 6 feet away from the main service panel (200amp service). The main panel and all of the wiring in the house was replaced about 2 years ago (very old house). I only had two slots left in the main panel and I needed to add circuits for my beer brewery (30amp 240v) and several circuits for my shop tools, hence the decision to do a sub panel. I was hoping to share the details and pictures of what I did and get thoughts on whether everything looks good or if I made an egregious errors before I schedule the inspection. So here goes:

1. I used 1-1/4 PVC conduit to connect the two panels. The conduit take a total of 4 90degree turns due to the way the concrete walls are in the basement. I believe this should be fine with respect to code. The conduit is fastened to the overhead joist in two places, each < 36" from the panel.

2. I used a Homeline 100amp sub panel and added a ground bus. I removed and discarded the neutral screw, so the ground and neutral is isolated in the sub panel.

3. I used #2 THHN wire for the two hot legs and neutral leg and #6 THHN for the ground.

4. In the main panel (QO), I used a 100amp two pole breaker and added a lug on the neutral bus to accommodate the #2 THHN neutral wire.

5. In box panels the neutral wire used was black so I marked each end with white electrical tape. Do I need to mark the hot legs as red and black or can they both be black?

I think that is the major details. Take a look at the pictures - did I make an errors? Also a few questions:

1. Notice that where the sub panel is mounted the concrete wall angles back a bit above the panel. I need to run a few lines down to 20a breakers in the sub panel for the shop circuits, do I need to place a piece of wood behind the romex or is it sufficient to tack the wire at the joist above the panel?

2. The other project I did at the same time was to install a generator transfer switch (see pic - black box next to main panel). Notice here how the wire is tacked to the plywood the switch is mounted on and then again at the joist above, but has nothing behind it for about a foot or two of vertical space - is this allowed?

3. I ran #10 romex underground feeder wire to the outside of the house for the generator inlet box. After I ran the wire in the basement along the rim joist I had some insulation work done. The insulation contractor spray foamed over the wire. Do you think this will be an issue when it comes to inspection?

4. The underground feeder wire when it exists the house goes through a short (2ft) vertical length of PVC conduit to provide protection before entering the the generator inlet box. Do you think this is an issue? From what I can tell from the NEC, romex should not be run in conduit, but it is allowed for short lengths to provide protection.

Well, that's a big post. Thanks for reading and your thoughts.
 
Attached Images       
Sponsored Links
  #2  
Old 11-13-13, 12:19 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Welcome to the forums!

The neutrals appear to be isolated in your subpanel. Are they?

Why 100A? Seems like overkill.

You're the one who's familiar with your work and can go look at something if there's a question, I suggest you compare what you have with Sub Panel Diagrams, one of the sticky notes at the top of the list of threads in this forum.

You need the plywood above your subpanel.

Secure the cable for your ATS closer to the edge of the back board.

I ran #10 romex underground feeder wire
No such critter. The cable that's visible in your picture appears to be Type UF, Underground Feeder, not Type NM, aka "Romex®."

After I ran the wire in the basement along the rim joist I had some insulation work done. The insulation contractor spray foamed over the wire. Do you think this will be an issue when it comes to inspection?
It shouldn't be.

The underground feeder wire when it exists the house goes through a short (2ft) vertical length of PVC conduit to provide protection before entering the the generator inlet box. Do you think this is an issue?
Not if it's Schedule 80 PVC.

From what I can tell from the NEC, romex should not be run in conduit, but it is allowed for short lengths to provide protection.
Yes, Type NM can be sleeved in open conduit - not run in a conduit system. But you didn't use Type NM. The Type UF you used is rated for use in conduit.

You can check out Congratulations! You have a Generator, another of the sticky notes, for more information relative to installing a backup power system.
 
  #3  
Old 11-13-13, 12:55 PM
Member
Thread Starter
Join Date: Nov 2013
Location: USA
Posts: 6
Thanks for the feedback - I did just find the stickies and will take a look through them. You also confirmed my suspicion that I need to extend the plywood up to the joist. Do you think that holds true for behind the UF coming out of the ATS?

No such critter. The cable that's visible in your picture appears to be Type UF, Underground Feeder, not Type NM, aka "Romex®."
You are correct - I used UF. I called it the wrong thing, but it's an important distinction.

One more question - where the conduit takes a turn upward out of the main panel, the conduit does not sit flat against the wall - should it? Is it sufficient that it is clamped above to the joist or should I try to slide and mount a piece of plywood behind it?
 
  #4  
Old 11-13-13, 03:11 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Do you think that holds true for behind the UF coming out of the ATS?
No:
Originally Posted by Nashkat1
Secure the cable for your ATS closer to the edge of the back board.
Is it sufficient that it is clamped above to the joist or should I try to slide and mount a piece of plywood behind it?
I can't tell for sure from a picture, but having a clamp on that first vertical section would help.
 

Last edited by Nashkat1; 11-13-13 at 04:30 PM.
  #5  
Old 11-13-13, 03:47 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,385
From what I can tell from the NEC, romex should not be run in conduit, but it is allowed for short lengths to provide protection.
My opinion is that it isn't a good practice to run NM cable (aka romex) in conduit system, but it isn't forbidden by the NEC.
 
  #6  
Old 11-13-13, 07:59 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,279
The conduit should be secured within 3' of termination to a box. They make many types of attachment fittings, some that will stand the conduit off the wall.
 
  #7  
Old 11-13-13, 08:57 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Thanks, Tolyn, I couldn't remember the current distance offhand.

SirFix, you can make the first clamp on the side of that white beam overhead.

They make many types of attachment fittings, some that will stand the conduit off the wall.
I've always found those to be a lot easier to install before I ran the conduit.
 
  #8  
Old 11-14-13, 02:31 AM
Glennsparky's Avatar
Member
Join Date: Nov 2011
Location: USA
Posts: 136
.5. In box panels the neutral wire used was black so I marked each end with white electrical tape. Do I need to mark the hot legs as red and black or can they both be black?
Leave them black. Color taping is not necessary.
1. Notice that where the sub panel is mounted the concrete wall angles back a bit above the panel. I need to run a few lines down to 20a breakers in the sub panel for the shop circuits, do I need to place a piece of wood behind the romex or is it sufficient to tack the wire at the joist above the panel?
Wood. I believe cables need to be secured within 12 inches of the panel.
2. The other project I did at the same time was to install a generator transfer switch (see pic - black box next to main panel). Notice here how the wire is tacked to the plywood the switch is mounted on and then again at the joist above, but has nothing behind it for about a foot or two of vertical space - is this allowed?
Because of the touchpad behind the cable, the inspector may ask for physical protection. Sleave the cable through a short piece of pipe and strap the pipe at both ends.

I believe you need to strap the whip that goes between the ATS and the main panel.
 

Last edited by Glennsparky; 11-14-13 at 02:47 AM.
  #9  
Old 11-14-13, 07:03 AM
Member
Thread Starter
Join Date: Nov 2013
Location: USA
Posts: 6
Thanks, everyone, for the feedback. I have the conduit strapped to the white beam overhead on both sides - so that should be good to go. My punch list is now to add plywood above the sub panel, strap the whip from the ATC, and sleeve the UF coming out of the ATS. Easy enough!

The neutrals appear to be isolated in your subpanel. Are they?
Nashkat: I have removed the ground bonding screw in the sub panel. Is this what you were asking?
 
  #10  
Old 11-14-13, 07:19 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,047
Yes, that was what Nash was asking.
 
  #11  
Old 11-14-13, 11:17 AM
Member
Thread Starter
Join Date: Nov 2013
Location: USA
Posts: 6
I really appreciate the help - I have one more question:

Because of the touchpad behind the cable, the inspector may ask for physical protection. Sleave the cable through a short piece of pipe and strap the pipe at both ends.
Can I used sch 40 for this? Alternatively, would it work to just mount a piece of wood behind the cable? See pic for example, but if I went that route I would use a thicker/wider piece of wood.
 
Attached Images  
  #12  
Old 11-14-13, 08:51 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Nashkat: I have removed the ground bonding screw in the sub panel. Is this what you were asking?
Originally Posted by ray2047
Yes, that was what Nash was asking.
That probably does answer my question, but I'd be more satisfied if you said you'd used a meter to confirm that there's no continuity between the neutral bus and the panel enclosure.

Can I used sch 40 for this?
Yes. It isn't likely to be shattered by an accidental kick or a string trimmer in that location.

Alternatively, would it work to just mount a piece of wood behind the cable? See pic for example, but if I went that route I would use a thicker/wider piece of wood.
No. The comment is about physical protection, not physical support.

Keep in mind that a sleeve isn't connected to any enclosure - it's just a sleeve.
 
  #13  
Old 11-15-13, 06:51 AM
Member
Thread Starter
Join Date: Nov 2013
Location: USA
Posts: 6
Thanks, that's helpful. I have some scrap sch 40 that will be just long enough.

I did confirm that the neutral is isolated from the enclosure with a meter before I did the install. Since the neutral and ground are bonded in the main panel I don't think I would get the same result now though - is that right?
 
  #14  
Old 11-22-13, 01:10 PM
Member
Thread Starter
Join Date: Nov 2013
Location: USA
Posts: 6
Just wanted to come back and say thanks for all of the input. I had the work inspected today and it passed with flying colors.
 
  #15  
Old 11-22-13, 01:26 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,047
Excellent! Thanks for the update.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes