How can I secure flex/BX from the *inside* of a box

Reply

  #1  
Old 11-25-12, 03:32 AM
Member
Thread Starter
Join Date: Jul 2009
Location: NYC
Posts: 302
How can I secure flex/BX from the *inside* of a box

If I can manage to get the knockout dealt with from the *inside* of the box, and then fish a new run to it , whether it be flex or BX - is there any advice you can offer on how to SECURE the cable to the box . All the fittings that are meant to secure it are generally from the outside in. Cutting the wall open is not a option as no access from the back *exterior* and the front is tiled.
 
Sponsored Links
  #2  
Old 11-25-12, 05:06 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
If you can manage to get the knockout and the cable run, you can attach the AC fitting to the end of the cable before you start fishing it and secure it with the provided nut on the inside of the box as normal. Be sure to use the non shorting bushing that comes with the fitting. There are no fittings to my knowledge that you can use inside a box. There is no room for it and it will cause a hazard to have the metal sticking into the box, reducing the space you need for switches, etc.
 
  #3  
Old 11-25-12, 05:34 AM
Member
Join Date: Aug 2009
Location: USA
Posts: 4,942
You can also remove the existing box and reinstall with an old work box. That will allow you to attach the cable with the box outside the wall and then install the box. If you have several cables entering different sides, this will be difficult if not impossible.
 
  #4  
Old 11-25-12, 08:14 AM
Member
Thread Starter
Join Date: Jul 2009
Location: NYC
Posts: 302
Chandler -

That was Genius. Just prefit the end and fish it with it.
It never even crossed my mind..
 
  #5  
Old 11-25-12, 08:45 AM
Member
Join Date: Jun 2012
Location: USA
Posts: 1,043
If it is a 1/2" knock-out then fishing cable with the fitting on it is the way to go. If it has two small knock-outs on each end of the box with a slot in it then it is meant to have a double internal clamp. Big box stores don't sell them individually but have them for some of the metal boxes.
[ATTACH=CONFIG]5941[/ATTACH]

TP900 - MC BX CLMP WITH SCREW REPLAC PART | Westway Electric Supply
 
Attached Images  
  #6  
Old 11-25-12, 09:29 AM
Member
Thread Starter
Join Date: Jul 2009
Location: NYC
Posts: 302
I've always used the knock out fittings.

Riddle me this....those clamps *which I'm familiar with*, are those rated for both MC and AC cable. And or why 1 and not the other..
 
  #7  
Old 11-25-12, 09:40 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 46,285
They are rated for both Armour clad and Metal clad cables.
 
  #8  
Old 11-25-12, 09:48 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,288
The fittings that are rated for MC cable, but not AC cable, is because they are not rated for grounding. With AC cable the jacket, in conjunction with the bonding strip, is your grounding path and the fitting is not rated for that. Standard MC cable has a separate grounding conductor.

The Exception is MCAP which also uses the jacket as the grounding path. With MCAP you need to make sure that you use approved fittings. Long story short, any fitting that is approved for AC is also approved for MCAP. http://www.southwire.com/documents/L...olidMCAP_2.pdf

When fishing the cable/fitting use one that uses a locknut, and remember to remove the locknut before fishing the cable in.
 
  #9  
Old 11-25-12, 12:08 PM
Member
Thread Starter
Join Date: Jul 2009
Location: NYC
Posts: 302
Oh. So close yet so far.
All the bottom holes on this 4" Box are populate. Managed to get a knockout on the top. Got my fish through....but between the deep box fairly flush to the wall and the knockout being on top, it just won't budge that last inch where I need the cable with the fitting to HUMP over to the top....


Before I start going to town, plan to take a breather - then drillout a knockout from the back, wedge it out....and then reattemp this again from the back.

In an ideal world, I would have just fished it right up, coming from the bottom to a bottom knockout
 
  #10  
Old 11-25-12, 12:14 PM
Member
Thread Starter
Join Date: Jul 2009
Location: NYC
Posts: 302
For those that have more experience hands....bearing the above statement, do you think a romex fitting is a slightly lesser bulkier....and might pull better if the cable is coming from below but I'm pulling to a knockout ONTOP of the Box.

Romex has been allowed for the last couple years in NYC but been slinging BX all my life and have only used Romex between a LV transformer to undercabinet electrical stuff
 
  #11  
Old 11-25-12, 12:51 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
As long as romex (12-2 wg nm for instance) is approved for use in your municipality, then, yes, I would pull it rather than AC. Here, again, you may want to attach the strain relief to the romex, about a foot or more down the cable, then fish the cable in, and pull it until the fitting sits in the hole, then slap on the nut to hold it.
 
  #12  
Old 11-25-12, 12:54 PM
Member
Thread Starter
Join Date: Jul 2009
Location: NYC
Posts: 302
Yeah. I think I might have better success with Romex as it can Kink More.
I've got most of the cable in the box. It's just that last 2 " with the fitting that I just can get over to the top of the box
 
  #13  
Old 11-25-12, 01:33 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
You may could have used a 90 degree AC fitting and come through a hole in the back of the box. Just sayin..............
 
  #14  
Old 11-25-12, 02:14 PM
Member
Thread Starter
Join Date: Jul 2009
Location: NYC
Posts: 302
Ha. The only reason I went for the top knockout *knowing I might get jammed up* like I am right now was that it was a clear shot to work with.
The fill of the box - in front of the back center has 5 or 6 pairs of 12 gauge pigtailed into one web I don't really work through

I've left my existing drag and plan to regroup for another day.
The wifey want's her countertop back
 
  #15  
Old 11-25-12, 04:27 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,288
IF you can get the fitting close to the KO, you can sometimes jamb a narrow screwdriver between the drywall and the box and use that to pry the fitting into the hole. The device plate will cover any damage you may cause.
 
  #16  
Old 11-25-12, 05:43 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
Now I am getting concerned with your box's fill. Is this a device box or a junction box? You may have it overloaded with cables to begin with. What size is the box. LxWxH?
 
  #17  
Old 11-25-12, 06:14 PM
Member
Thread Starter
Join Date: Jul 2009
Location: NYC
Posts: 302
Device Box. She's all buttoned back up but a wild guess would be 4 1/2 4 1/2 x 3" Deep box with a Mud Ring so make that 3 1/4"ish Depth. Just a single receptacle in there. 5 Pair 12 gauge for sure. The goal of this was to add a second recept - on a different circuit.
 
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