Drilling a new hole in a service panel

Reply

  #1  
Old 03-24-14, 08:42 PM
Member
Thread Starter
Join Date: Mar 2014
Location: USA
Posts: 7
Drilling a new hole in a service panel

I'm in the planning stages of replacing a split bus panel that violates the 6 throw rule with a new 200 amp Cutler-Hammer CH 42 space load center. The old panel's service entrance was drilled in it and, unfortunately, doesn't line up to the positioning of the standard knockouts. The service comes from the back of the meter base through the wall of the garage and straight into the panel. It is mounted in the wall between studs, so I don't have any lateral movement. The pictures, hopefully, show what I'm talking about. The picture of the Cutler-Hammer has a proposed location of a new hole towards the bottom on the left side. If it's drilled in that location, would I still be able to place breakers near the hole?

What alternatives to drilling do I have? Run conduit or service entrance cable out of the bottom or side of the meter base?
 
Attached Images   
Sponsored Links
  #2  
Old 03-24-14, 09:30 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,361
It will be tight but as long as the locknut fits I think you might be able to do it. The larger conductors are going to impinge on the space to wire the breakers. Could the panel be mounted higher to get below the breakers? I would have inverted the panel.
 
  #3  
Old 03-24-14, 10:10 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: NJ - USA
Posts: 43,494
I believe that black circle has been drawn in as the future hole.
I totally agree on flipping the panel over. The only problem is the neutral bar is going to be an issue.


Name:  ServicePanelhole.jpg
Views: 2305
Size:  23.3 KB
 
  #4  
Old 03-25-14, 06:58 AM
Member
Thread Starter
Join Date: Mar 2014
Location: USA
Posts: 7
I had considered inverting the panel, but that would leave some breakers higher than 6'7". I should note that the current hole is 5'1" from the floor of the garage which has made it difficult to place the new panel without violating the maximum height rule.

Perhaps I should look into 30 space/40 circuit or 20 space/40 circuit panels. I didn't really want to have tandem breakers, but I may not have much choice.

Another question I had is, if I need to position the panel such that the cable sheaths on the cables coming in from the top no longer enter the panel, how do I solve that problem?
 
  #5  
Old 03-25-14, 05:24 PM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,131
Are you saying the cables will be to short? If you may need to install a short piece of 4"x4" trough on top and nipple into the panel, if you have the space.
 
  #6  
Old 03-25-14, 06:13 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 11,984
You can also splice the service wires and make them longer to reach the main breaker on the top. I suggest an insulated wire splice like this:

Name:  connect.png
Views: 2250
Size:  35.0 KB
 
  #7  
Old 03-25-14, 08:02 PM
Member
Thread Starter
Join Date: Mar 2014
Location: USA
Posts: 7
Originally Posted by Geochurchi
Are you saying the cables will be to short? If you may need to install a short piece of 4"x4" trough on top and nipple into the panel, if you have the space.
The first issue is, if I have to move the panel down from where the old one was, it may be that the cable sheath would no longer extend at least 1/4" inch into the panel. The second issue is, since it's a split bus, the larger breakers (a 40 amp for air conditioner, 40 amp for range, 30 amp for dryer) on the top row and the wires will need to be spliced to extend down to a normal bus position. The splices, I believe, can be done in the panel. After looking at cable troughs like you suggested, that would seem to solve this particular problem.

However, if I need to extend the panel even lower, I would have to splice the larger wires from the a/c, range, or dryer, outside the panel. It looks like Tolyn's suggestion would work in this situation (thanks for the suggestion, Tolyn). Will those splices have to be housed in a junction box?

Unfortunately, the old panel as installed really limits my options. From the service entrance hole in the old panel not matching up to a standard knock out position (on the horizontal plane) to the height of the service entrance hole for the old panel limiting my options for vertical adjustment of the new panel, the way the old panel was installed seems to hinder my ability to make a clean install of the new one.
 
  #8  
Old 03-25-14, 08:09 PM
Member
Thread Starter
Join Date: Mar 2014
Location: USA
Posts: 7
Here's a picture of the top of the panel and a picture of where the wires come in from the ceiling of the garage. There's about 18 inches between.
 
Attached Images   
  #9  
Old 03-26-14, 05:20 AM
Member
Join Date: Mar 2014
Posts: 363
Just a suggestion, and can't really tell the space you have but did you consider instead of using the new box as you main maybe you can use a main breaker box as you main service disconnect where the power comes into the garage. This way you will have more room available in the main box to manage the service entrance cables coming into it Then place the new breaker box near the main disconnect and connect it with an SER cable. You would want to be sure that you can place the main disconnect box where the service entrance cables come in and position the near breaker box close enough so the existing circuit wires are close enough to reach the breakers on their new breaker box. If you do consider this the breaker box must be set up with separate ground and neutral bars where as on the main disconnect the ground and neutral bars are bonded together. I have had this in the field before where the service entrance cable was far too short to reach the available space for the new breaker box. I set up a new main disconnect, ran the service entrance cables to that. Then ran the required size SER cable from the main disconnect to the new breaker box. Also since I had to place the new breaker box further away the existing circuit wires would not reach the breakers. Therefore I set up and installed junction boxes for the existing circuits and ran new wires from the junction box to the circuits on the new box. It sounds like it may be a lot of extra work but sometimes it saves a lot of work in the end so that you don't have to man-handle the service entrance wires coming into the new box. If you are doing 200A service you will need 4/O wires and they are not easy to bend. (Note: bending radius rules for wires). Meaning, just because you can bend a wire to where you want it to go does not mean it is by code.

As for the existing pre-drilled hole in the new service box that you have you can just buy a knockout cap that snaps right in; about $1.50 by code there can not be any open holes in the breaker box.
 
  #10  
Old 03-26-14, 06:46 AM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,131
Another option might be to install a large pull box under the panel ,punch the knockout to line up with the service cable from the meter and make the splices for the service cables there using the splice kits Tolyn suggested install a close nipple between them ,that way would allow you to move the panel up and avoid splicing all the other cables.
There is no easy way!
Geo
 
  #11  
Old 03-26-14, 08:03 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,213
I don't think the panel replacement has to be as difficult as it's being made out to be. The existing service entrance wiring comes from the back of the meter socket through the wall into the existing panel. I believe in this case I'd install a new 4/0 AL SEU cable from the bottom of the meter socket down the wall 1 or 2 feet, penetrate the wall and then turn it up and bottom feed the new inverted panel. The new panel could be mounted at the same height as the existing panel. The existing 2 1/2" hole in the back of the socket would have to be closed.
 
  #12  
Old 03-26-14, 08:23 AM
Member
Thread Starter
Join Date: Mar 2014
Location: USA
Posts: 7
Thank you AFJES, Geochurchi, and CasualJoe for the suggestions. The disconnect and pull box are interesting ideas, but I like Joe's idea of SEU cable out from the bottom of the meter base through the wall and into the bottom of an inverted panel. It seems the simplest and most cost effective solution. I will research the code requirements of running the SEU.

Originally Posted by CasualJoe
I believe in this case I'd install a new 4/0 AL SEU cable from the bottom of the meter socket down the wall 1 or 2 feet, penetrate the wall and then turn it up and bottom feed the new inverted panel.
Is there a minimum bending radius for the cable? If I go through the wall and up to the panel, the bend will be pretty severe.
 
  #13  
Old 03-26-14, 04:46 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,213
Is there a minimum bending radius for the cable? If I go through the wall and up to the panel, the bend will be pretty severe.
I honestly don't know if there is a minimum bending radius, but I have seen it done similar to this before. It won't be a tight bend and you'll have to use duct seal at the penetration to seal the opening. You could use also 2/0 copper SEU cable, but you'd probably have a hard time finding it, my guess is it would be a special order through a supply house. The big advantage is you can mount the new panel at the same height as the existing panel.
 
  #14  
Old 03-27-14, 04:12 AM
Member
Join Date: Mar 2014
Posts: 363
According to NEC 2011 and 2014:

334.24 Bending Radius
Bends in Types NM, NMC, and NMS cable
shall be so made
that the cable will not be damaged. The radius of the curve of
the inner edge of any bend during or after installation shall not
be less than five times the diameter of the cable.

338.24 Bending Radius
Bends in Types USE and SE cable
shall be so made that the cable
will not be damaged. The radius of the curve of the inner edge of
any bend, during or after installation, shall not be less than five
times the diameter of the cable.

The above is what I normally follow.
 
  #15  
Old 03-27-14, 07:14 AM
Member
Thread Starter
Join Date: Mar 2014
Location: USA
Posts: 7
Originally Posted by CasualJoe
I honestly don't know if there is a minimum bending radius, but I have seen it done similar to this before. It won't be a tight bend and you'll have to use duct seal at the penetration to seal the opening. You could use also 2/0 copper SEU cable, but you'd probably have a hard time finding it, my guess is it would be a special order through a supply house. The big advantage is you can mount the new panel at the same height as the existing panel.
So, duct seal on the penetration into the garage. I'm assuming I need a water tight connector for the SEU coming out of the meter base?

Even if I could find 2/0 copper cable, I imagine, for even a short run like I need, it wouldn't be worth the extra cost compared to 4/0 aluminum.

Is it possible my AHJ might require conduit for the service entrance on the exterior of the house? I'm coming up with a list of questions to ask the inspector and I'm wondering if this is something that would be worthwhile to ask.

Originally Posted by AFJES
334.24 Bending Radius
Bends in Types NM, NMC, and NMS cable shall be so made
that the cable will not be damaged. The radius of the curve of
the inner edge of any bend during or after installation shall not
be less than five times the diameter of the cable.

338.24 Bending Radius
Bends in Types USE and SE cable shall be so made that the cable
will not be damaged. The radius of the curve of the inner edge of
any bend, during or after installation, shall not be less than five
times the diameter of the cable.
It looks like if I go by the diameter of the cable, the bend radius would be about 4 or 5 inches. I don't know if I'll be able to do that.
 
  #16  
Old 03-27-14, 09:33 AM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,131
No need for a Water tight connector coming out of the bottom or back of the socket,as for the bend radius of the SEU I have never run across an inspector that had an issue with the bend required to go from the meter to the panel usually there is not that much space to work with.
 
  #17  
Old 03-27-14, 09:47 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,361
Once the cable enters the panel you are dealing with conductors, not a cable. The bend radius would change.
 
  #18  
Old 03-27-14, 09:53 AM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,131
One thought about inverting the panel,make sure the cover will if either way otherwise the index and other info will be upside down, not a big deal but it makes a better job if it is right.
 
  #19  
Old 03-27-14, 11:19 AM
Member
Thread Starter
Join Date: Mar 2014
Location: USA
Posts: 7
Originally Posted by Geochurchi
No need for a Water tight connector coming out of the bottom or back of the socket,as for the bend radius of the SEU I have never run across an inspector that had an issue with the bend required to go from the meter to the panel usually there is not that much space to work with.
That's good to know. It seemed kind of impractical to have such a large bend radius, but then again sometimes, when it comes to code requirements, impractical is what you're left with.

Originally Posted by pcboss
Once the cable enters the panel you are dealing with conductors, not a cable. The bend radius would change.
I don't think I'll have an issue after it enters the panel. The panel will be inverted, so it'll just be a straight shot to the lugs. My concern, since the cable will be running between wall studs, is the bend radius going from having the cable secured to the outside of the house, coming through the exterior wall, then bending it up and into the panel will have to be roughly 2 inches maximum. If others' experience with inspections is any indication, though, it shouldn't be an issue.

Originally Posted by Geochurchi
One thought about inverting the panel,make sure the cover will if either way otherwise the index and other info will be upside down, not a big deal but it makes a better job if it is right.
Good note, thanks. I'll keep that in mind when installing the panel.
 
  #20  
Old 03-27-14, 01:14 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,213
No need for a Water tight connector coming out of the bottom or back of the socket
Nor would you need a water tight connector at the sides of the socket. Anywhere you find factory punched concentric knockouts, no need for a water tight connector.
 
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
'