Hi,
I’ve been asked to put in a couple of outlets in an office with armored cable, but all the drywall is up and painting done – with faux painting techniques that would be impossible to touch-up.
I can’t seem to find an “old work” metal boxes for retrofit installation with BX cable. Naturally, I can’t use the Carlon blue boxes and good ol’ Romex, so what are my options (if any)? Is there such a thing as an “old work” metal box, and if not, why not?
Thanks for any help!
Jcd
Replies
Yes there are 'old work' boxes that will work. Usually available at the 'Big box' or any decent electrical supply house. Most common is the 'gangable', if you have need of more than one device in the box, steel boxes with wings top and bottom. Use 'F-clips', thin sheet-steel pieces that keep the box from falling out while the 'wings' keep it from falling in.
Trick is to cut the hole clean an feed only the wires into the box before the box is firmly mounted. Once the box is in pull the wires, hook them on the other end of the run, to pull the connector into the bottom, or top, of the box and hold it while you spin on the locknut.
Some AHJs, inspectors, will allow you to use, if the wall is deep enough, a 90 degree connector attached to the armor and coming into the back of the box. Some AHJs won't. Controversy is that 90 degree connectors have to be accessible. Some AHJs see it as being accessible by removing the box. Others don't.
More recently there are some blue Carlon boxes with KOs that will take a BX, or conduit, connector. Note you need to use a grounding bushing on the connector inside the box so that the BX is properly grounded. Connect the bushing to the ground wire inside the box. Fail to do it right and a short within the BX can 'cook' and cause a fire inside the wall. Do it right and everything is fine.
I have used a lot of metal old work boxes that work with BX. The corners are cut at 45 degrees, so you can easily attach the BX without a 90 degree connector.
Edited 12/12/2004 2:40 am ET by nikkiwood
Here are some pictures.
Here are two styles of old work metal boxes.
http://www.wellspent.org/Product?p=35393
http://www.acehardware.com/product/index.jsp?productId=1297230&cp=1254879.1254958.1304371&page=3&pageBucket=0&parentPage=family
And here are the F clips AKA Madion Clips.
http://www.foxelectricsupply.com/content/products/ProductDetail.asp?qsCatID=24597&qsProductNo=977
This is the best thing that I could find showing the use of the F clips.
http://www.prescolite-lsp.com/documents/install/ERC-2R_Install.pdf
Slide the long arm between the box and the SR so that it catches the SR at the top and the bottom. Them fold the two tabs over edge of the box to the inside. One clip on each side of the box.
I also found these Molley clips for old work boxes. Don't know how they work.
http://www.foxelectricsupply.com/content/products/ProductDetail.asp?qsCatID=24597&qsProductNo=OWC
Thanks folks - this is very reassuring. The local HD didn't have a clue, and nothing I saw looked to work, but I think the missing link I wasn't on the lookout for was the retaining clips, which may be sold separately. I'll go back and have another look, now that I know this DOES exist.
Thanks again and happy holidays to everyone!
Jcd
I'll go back and have another look,
Uh .... Why?
Be adventurous ... and find a real electrical supply house.
just imagine the possibilities ....
Like them actually knowning what ya need and saving 2 trips each time?
Jeff Buck Construction
Artistry in Carpentry
Pgh, PA
:) Okay, I'm laughing my head off at your comment...
So very true, I know, I know... Like the rest of us unfortunate souls, I just "end-up" at HD far too often, and it happens to be 1/2 mile from my office - well, you know how it is: laziness breeds complacency and acceptance, and finally, defeat ;)
I'm ashamed and will go find a good supply house ASAP!
Cheers,
Jcd