FMC vs AC/BX


  #1  
Old 12-07-14, 04:32 PM
B
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 303
Upvotes: 0
Received 0 Upvotes on 0 Posts
FMC vs AC/BX

Can someone tell me if there is a difference in terms of code between Flexible Metal Conduit and Armoured Cable? I've got a very short run (about 2') of AC and I like the idea of an FMC rather than AC as it'll be easier to cut. It's just a run of 14\2.
Thanks!
 
  #2  
Old 12-07-14, 05:09 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,332
Received 877 Upvotes on 740 Posts
No differences for code, just different wiring methods with different rules to follow. If you want to use FMC, go ahead. While code does not require it for a 2' run, I would recommend pulling in a ground wire.
 
  #3  
Old 12-07-14, 05:38 PM
B
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 303
Upvotes: 0
Received 0 Upvotes on 0 Posts
Any chance I'll be able to just pull Romex through?
 
  #4  
Old 12-07-14, 05:49 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,976
Received 194 Upvotes on 170 Posts
Why are you pulling NM through the flex?
 
  #5  
Old 12-07-14, 05:53 PM
B
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 303
Upvotes: 0
Received 0 Upvotes on 0 Posts
Just looking for a simple way to guard the NM. I need to do a short run from a box to and external transformer. Transformer can't be covered, but AC needs to be protected. Easier to use the NM I already have.
 
  #6  
Old 12-07-14, 06:19 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 9,871
Received 185 Upvotes on 166 Posts
Neither AC or NM cable can be used outside. Is it just entering the transformer through the back from inside the house?
 
  #7  
Old 12-07-14, 07:52 PM
B
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 303
Upvotes: 0
Received 0 Upvotes on 0 Posts
It's not outside at all. It's a run from a wall box to an LED transformer/rectifier. It's on top of my cabinets. 120ac comes up from the basement to a wall switch. Switched 120ac up to above the cabinets where a transformer exists. Then the 12vdc back down to the leds undercabinet.
 
  #8  
Old 12-08-14, 04:12 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,976
Received 194 Upvotes on 170 Posts
If the NM is not subject to damage you can run it on the surface.
 
  #9  
Old 12-08-14, 04:57 AM
B
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 303
Upvotes: 0
Received 0 Upvotes on 0 Posts
Really? Could on top of a cabinet be concerned subject to damage?
 
  #10  
Old 12-08-14, 05:07 AM
W
Member
Join Date: Feb 2006
Location: USA
Posts: 6,395
Received 63 Upvotes on 55 Posts
Cabinets

Is the top of the wall cabinets the usual 84 In. high?
 
  #11  
Old 12-08-14, 06:07 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,976
Received 194 Upvotes on 170 Posts
I would not consider the top of a cabinet to be subject to damage.
 
  #12  
Old 12-08-14, 06:59 AM
B
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 303
Upvotes: 0
Received 0 Upvotes on 0 Posts
One place is 84" and the other is probably 90" (we have 9' ceilings).

And I did email the city inspector to see what he would consider "subject to damage" since he's the one that ultimately signs the paper :-)
 
  #13  
Old 12-08-14, 01:39 PM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 9,785
Upvotes: 0
Received 45 Upvotes on 43 Posts
It is pretty common to poke some Romex out of the drywall on top of the cabinets to power the light transformer. I don't expect there to be any problem from the inspector on this one.
 
  #14  
Old 12-08-14, 02:02 PM
B
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 303
Upvotes: 0
Received 0 Upvotes on 0 Posts
really? And I could get away without a junction box up there too then? Wouldn't I need some sort of strain relief to make sure the Romex doesn't get yanked or anything?
 
  #15  
Old 12-08-14, 02:13 PM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 9,785
Upvotes: 0
Received 45 Upvotes on 43 Posts
Depends on whether or not the transformer itself is a rated j-box. Many have 1/2" KOs you can put the Romex clamp in.
 
  #16  
Old 12-08-14, 04:46 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,332
Received 877 Upvotes on 740 Posts
If you want to protect the cable with FMC, that is also fine. We do it all the time to protect cables in cabinets.
 
  #17  
Old 12-08-14, 05:24 PM
B
Member
Thread Starter
Join Date: Nov 2010
Location: USA
Posts: 303
Upvotes: 0
Received 0 Upvotes on 0 Posts
Yeah this transformer has knock outs so that's covered with no problem. Still haven't heard back from the inspector. Maybe just have to call.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: