View Full Version : BX to Romex?
WKL3
Apr 19, 2009, 06:00 PM
I have an older home with the metal sheilded 2 conductor cable. 2 20 amp lines were added to the kitchen, but still using the metal sheilded 2 conductor cable. Is it OK to connect this in a box to romex? [grounding the ground to the sheild] The kitchen is being updated again. I am very handy (ex automechanic) and will add one GFI protected outlet every 24 inches of counter.
ohb0b
Apr 19, 2009, 07:40 PM
Check your local codes... there may be a reason they used "BX" (Almost no one calls it that anymore, you must be an old guy!) instead of Romex.
Missouri Bound
Apr 19, 2009, 08:04 PM
Ohbob... methinks you must be a young guy... and have no idea what BX is... right?
KISS
Apr 19, 2009, 08:08 PM
FWIW:
What is Romex/NM/NMD? What is BX? When should I use each? (http://www.faqs.org/faqs/electrical-wiring/part2/section-5.html)
ohb0b
Apr 19, 2009, 10:41 PM
Wish I was a young guy!
Type NM (Non-Metallic Sheathed) cable is commonly called "Romex." Which I believe is a trademark of the Rome Cable Company. In Canada, there is a similar product called "Lumex."
As for "BX" the NEC calls it Type AC (Armor Clad) or Type MC (Metal Clad) They both have a spiral wrap armor. The chief difference between the two types is the insulation of the underlying wires. There is also a smooth sheath MC cable, which is not commonly used.
I can't verify this, but here is the story I heard: There once was a Greenfield company, who manufactured flexible conduit. (Metallic Flexible Conduit is still referred to as "Greenfield" in the trade.
The story goes, they used to rope houses with flexible conduit, then fish wires through it. Someone at Greenfield developed a conduit with wires already installed... it was their "B" product line, and it was eXperimental. I can't verify this tale, but it sounds too good to be true.
Type NM (Romex) is used mainly in residential construction. Some areas of the country, the local code specifies armor clad cable, usually for protection against rodents.
If Romex is approved for your location, you may continue the existing "BX" run in Romex, as long as you make the termination inside an approved box. (NEC 320.40)
stanfortyman
Apr 20, 2009, 04:30 AM
BX must be more of a locational thing. Very few around here use the term AC. It's either BX or MC.
You have to remember, if the AC does not have the thing bonding strip the sheathing CANNOT be used as the equipment ground.
250.118(8)
320.100
Dpfiling
Apr 22, 2009, 02:55 AM
Stanfortyman is correct. The wound armored sheath is not permitted to be used as a grounding conductor. You must have a separate ground wire all the way back to the panel.
WKL3
Apr 26, 2009, 03:45 PM
Stanfortyman is correct. The wound armored sheath is not permitted to be used as a grounding conductor. You must have a separate ground wire all the way back to the panel.
Renovated Kitchen:
Stanforyman & all. As I understand things from reading, the NEC was updated in 2008 which included 250.118(8) which states that the Flexable Metal Shield is no longer acceptable for a ground.
Then, this requires a new NM 12 gauge Romex cable?? (one per circuit breaker) Sounds like I need to stop in the town office and talk to the inspector to learn the latest and greatest. The entire job will be inspected (I'm just running the electrical) and want no headaches.
stanfortyman
Apr 26, 2009, 05:11 PM
Stanforyman & all. As I understand things from reading, the NEC was updated in 2008 which included 250.118(8) which states that the Flexable Metal Shield is no longer acceptable for a ground.
This is nothing new. It has been this way since "modern" AC cable (with the bonding strip) was introduced many years ago.
lalo13187
Oct 22, 2013, 07:12 AM
What is the difference between romex and bx cable? I need answer asap please thanks
hfcarson
Oct 22, 2013, 09:12 AM
The fastest answer can be found on the internet...
You'll get pictures and everything and you won't have to wait...
donf
Oct 22, 2013, 10:24 AM
"NM" ("Romex", is a brand name) for a non-metal sheathed cable. AC ("BX" is Slang for Bronx, NYC where it was made originally) is a metal shielded cable.
ma0641
Oct 22, 2013, 02:03 PM
What is the difference between romex and bx cable? I need answer asap please thanks
Read the previous posts.