Connecting Romex to Armored Cable

Reply

  #1  
Old 03-29-15, 09:18 AM
Member
Thread Starter
Join Date: Mar 2015
Posts: 4
Connecting Romex to Armored Cable

Hi guys,

I'm currently renovating my home office and have a question.

The office was previously wired with BX cable (black and white wire wrapped in cloth). There were two wall sconces (with pull chain) and four outlets.

What I want to do is get rid of the BX that is in the room with the exception of the line coming in that feeds the power. Get rid of the two sconces and replace them with a ceiling light with a light switch, and three outlets.

The BX line coming in is too short (it was originally connected to one of the sconces). To get it to the light switch can I use a metal box, feed the BX into that and clamp it, then feed in Romex - ground it to a green screw, and connect the Black/Black and White/White wires together to create an extension?

Here's a picture of what I have so far:
Name:  IMG_20150329_092754.jpg
Views: 2158
Size:  40.4 KB

Also, for the sake of reference here are some diagrams I threw together to illustrate what I'm trying to do:

Old Wiring (all BX)
Name:  old-wiring.jpg
Views: 1425
Size:  18.8 KB

New Wiring (BX power feed, everything else upgraded to Romex)
Name:  new-wiring.jpg
Views: 1231
Size:  18.8 KB

Thoughts?
Thank you!
SB
 
Sponsored Links
  #2  
Old 03-29-15, 09:50 AM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,132
Your plan will work however you will have to many conductors in that box,actually you could install a 4" Sq. Box with single device plaster ring ,use a connector rated for MC on top and 2 Romex connectors on the bottom,the circuit will need to be protected by an AFCI device either a breaker or receptacle.
Geo
 
  #3  
Old 03-29-15, 10:24 AM
Member
Thread Starter
Join Date: Mar 2015
Posts: 4
Thanks @geochurchi, how do I install a 4" square box in the wall? I was going to use the single gang switch and just put a "blank" cover over it.

Take a look at the following, this is how I translated your reply.

Name:  facing-wall-2.jpg
Views: 2433
Size:  24.0 KB

So the power (BX cable) goes into the junction box. In that I would take romex down to the light switch and then from the switch, run a line to the ceiling light.

Also in the box with the BX cable would be a second run of wire which runs down to the outlet.

Does that look right?
 
  #4  
Old 03-29-15, 10:31 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,677
How old is the BX? Does it have a bonding strip/wire?

Name:  111ecmCBfig1.jpg
Views: 971
Size:  25.4 KB
 
  #5  
Old 03-29-15, 10:50 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: NJ - USA
Posts: 43,512
Like Geo mentioned you could use a 4" box and ring to do what you need.

Name:  1900combo.jpg
Views: 808
Size:  26.7 KB
 
  #6  
Old 03-29-15, 11:04 AM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,132
If you intend to blank off the box then that would work,just change the clamp for BX, also as Ray stated make sure it has the bond strip in the armor otherwise you can not extend that ungrounded circuit.
P/S use the deepest box you can get into the wall
Geo
 
  #7  
Old 03-29-15, 11:20 AM
Member
Thread Starter
Join Date: Mar 2015
Posts: 4
Hi @ray2047,

The house was built in 1932 so I think the BX is pretty old. There are remnants of knob and tube through the house as well, so I believe the BX came in at a later date. The cloth is pretty deteriorated at the ends so maybe 50 years old?

Here's a close up of the wire. I don't see anything that would look like a bonding strip. There is a brass/copper colored piece at the end of the cable. Not sure what that is for.

See below:
Name:  IMG_20150329_140947.jpg
Views: 622
Size:  34.0 KB

Name:  IMG_20150329_141008.jpg
Views: 591
Size:  27.5 KB
 
  #8  
Old 03-29-15, 12:07 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,677
I don't see anything that would look like a bonding strip.
That and the picture say it is unlikely your BX provides a reliable ground. Therefore you are going to need to run a new circuit from the breaker box.
 
  #9  
Old 03-29-15, 03:26 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,365
Another thing to consider is the load on the existing circuit that you are adding on to. I would run a new circuit even if the lack of grounding issue was not there.
 
  #10  
Old 04-02-15, 02:40 PM
Member
Thread Starter
Join Date: Mar 2015
Posts: 4
Thanks Ray. That's what I was afraid of. Appreciate everyone's help!
 
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
'