Brandon Whitmore Posted October 13, 2009 Report Share Posted October 13, 2009 Why do they typically install FMC as a sleeve over Romex when running power to a furnace, water heater, etc. Can someone give me the exact definition for "subject to damage" in regards to protection for exposed wiring. Reason I ask, is that according to the 2006 IRC table 3701.4, it lays out the allowable applications for wiring methods. The only methods allowed to be used for areas subject to damage are IMC, RMC, or RNC schedule 80. This seems odd to me. All wiring methods are allowed to be run exposed, just not where subject to damage. So why is it that FMC is allowed to protect Romex as a sleeve when it is not rated for protection against physical damage? Based on the table alone, I don't see how it should make much of a difference, common sense aside. Link to comment Share on other sites More sharing options...
Jim Katen Posted October 13, 2009 Report Share Posted October 13, 2009 Why do they typically install FMC as a sleeve over Romex when running power to a furnace, water heater, etc. Can someone give me the exact definition for "subject to damage" in regards to protection for exposed wiring. Reason I ask, is that according to the 2006 IRC table 3701.4, it lays out the allowable applications for wiring methods. The only methods allowed to be used for areas subject to damage are IMC, RMC, or RNC schedule 80. This seems odd to me. All wiring methods are allowed to be run exposed, just not where subject to damage. So why is it that FMC is allowed to protect Romex as a sleeve when it is not rated for protection against physical damage? Based on the table alone, I don't see how it should make much of a difference, common sense aside. I'm not particularly fluent in the electrical section of the IRC. But I have noticed that they've managed to take about 36 pages of worth of wiring methods from the NEC and condense them into three simple tables. It's really a nice bit of information management. However, it does seem to loose a bit in translation. I think that the crux of your question is the notion that the threshold for physical damage is the same for all wiring methods. It isn't. A situation that might cause physical damage to a length of NM cable might not cause physical damage to a length of FMC. The potential for damage is relative to the wiring method. - Jim Katen, Oregon Link to comment Share on other sites More sharing options...
Brandon Whitmore Posted October 13, 2009 Author Report Share Posted October 13, 2009 A situation that might cause physical damage to a length of NM cable might not cause physical damage to a length of FMC. The potential for damage is relative to the wiring method. Ahh, thanks. That would explain it, and makes sense. I chose to wire my "sub" panel in my garage with an exposed raceway of FMC. In my opinion, it would not be "subject to damage", but can't wait for the electrical inspector to call it out. Is there any definition of "subject to damage" that you feel would help inspectors determine whether to write up exposed wiring? Besides exposed Romex in a garage, are there any other wiring methods that you would write up, such as MC, AC, schedule 40, etc.? Link to comment Share on other sites More sharing options...
Jim Katen Posted October 14, 2009 Report Share Posted October 14, 2009 . . . Is there any definition of "subject to damage" that you feel would help inspectors determine whether to write up exposed wiring? I think that phrase universally escapes definition. Besides exposed Romex in a garage, are there any other wiring methods that you would write up, such as MC, AC, schedule 40, etc.? Not really. I don't even have a problem with NM in a garage, so long as it's done properly. I just use common sense most of the time. If something looks as if it's likely to get smushed or yanked on, I trot out the S2D card (subject to damage). - Jim Katen, Oregon Link to comment Share on other sites More sharing options...
Brandon Whitmore Posted October 15, 2009 Author Report Share Posted October 15, 2009 Thank you sir. Up 'til now, I've always written up any exposed Romex in garages or on the outside of any finished walls as subject to damage, and recommended protection. I wonder what others do? Link to comment Share on other sites More sharing options...
Jim Katen Posted October 15, 2009 Report Share Posted October 15, 2009 Thank you sir. Up 'til now, I've always written up any exposed Romex in garages or on the outside of any finished walls as subject to damage, and recommended protection. I wonder what others do? You'll find that the NEC doesn't back up that opinion. It specifically allows NM to be run exposed in 334.15. The cable has to closely follow the surface of the building and it has to be protected "where necessary" by conduit or somesuch. Oregon gets more specific. It adds the following detail: Exposed nonmetallic sheathed cable shall be protected where it is installed horizontally less than 8 feet above the floor. Exposed non-metallic sheathed cable less than 8 feet above the floor that enters the top or bottom of a panelboard shall be protected from physical damage by conduit, raceway, 1/2-inch plywood or 1/2-inch drywall. - Jim in Oregon Link to comment Share on other sites More sharing options...
Brandon Whitmore Posted October 16, 2009 Author Report Share Posted October 16, 2009 You'll find that the NEC doesn't back up that opinion. It specifically allows NM to be run exposed in 334.15. The cable has to closely follow the surface of the building and it has to be protected "where necessary" by conduit or somesuch. I guess that's one bonus to being an inspector. We can recommend stuff like this whether code or not--- this is good info. though. This part of the code is too vague to be helpful in my opinion. "Where Necessary", and "Subject to Damage" need specific definition, or it's to each his own when it comes to opinions/ interpretations on this matter--- arghhh. In my opinion, all exposed Romex within reach is subject to damage. Then again, I'll bet that more Romex is damaged when installed behind finished surfaces than where exposed. At least people can see the stuff and choose not to damage the stuff. Oregon gets more specific. It adds the following detail: Quote: Exposed nonmetallic sheathed cable shall be protected where it is installed horizontally less than 8 feet above the floor. Exposed non-metallic sheathed cable less than 8 feet above the floor that enters the top or bottom of a panelboard shall be protected from physical damage by conduit, raceway, 1/2-inch plywood or 1/2-inch drywall. Strange how the state is much more lenient on some code issues, while tougher on others. Is the horizontally run wire more subject to damage than vertical stuff, or is it a way of preventing people from using the exposed Romex as a clothes hanger and such? But wait, if next to the panel, vertical wiring must be protected-- huh? Link to comment Share on other sites More sharing options...
Jim Katen Posted October 16, 2009 Report Share Posted October 16, 2009 You'll find that the NEC doesn't back up that opinion. It specifically allows NM to be run exposed in 334.15. The cable has to closely follow the surface of the building and it has to be protected "where necessary" by conduit or somesuch. I guess that's one bonus to being an inspector. We can recommend stuff like this whether code or not--- this is good info. though. This part of the code is too vague to be helpful in my opinion. "Where Necessary", and "Subject to Damage" need specific definition, or it's to each his own when it comes to opinions/ interpretations on this matter--- arghhh. But they clearly intend that NM should be allowed to be run exposed in some situations. By the way, if you think that's vague, try interpreting 110.12. It says, "Electrical equipment shall be installed in a neat and workmanlike manner." How the heck do you interpret that? In my opinion, all exposed Romex within reach is subject to damage. Then again, I'll bet that more Romex is damaged when installed behind finished surfaces than where exposed. At least people can see the stuff and choose not to damage the stuff. So you wouldn't like this work: Click to Enlarge 40.24 KB Click to Enlarge 43.16 KB Click to Enlarge 41.03 KB Click to Enlarge 51.99 KB Oregon gets more specific. It adds the following detail: Quote: Exposed nonmetallic sheathed cable shall be protected where it is installed horizontally less than 8 feet above the floor. Exposed non-metallic sheathed cable less than 8 feet above the floor that enters the top or bottom of a panelboard shall be protected from physical damage by conduit, raceway, 1/2-inch plywood or 1/2-inch drywall. Strange how the state is much more lenient on some code issues, while tougher on others. Is the horizontally run wire more subject to damage than vertical stuff, or is it a way of preventing people from using the exposed Romex as a clothes hanger and such? But wait, if next to the panel, vertical wiring must be protected-- huh? An inspector explained it to me like this: the horizontal NM invite people to stick things behind it and hang stuff from it. In a garage, it's a good place to shove a rake handle, shovel handle, machete, etc. The same goes for the spot where the NM leaves the surface of the wall to enter a panel box. The cable forms a little triangular space that's handy to hook stuff onto. - Jim in Oregon Link to comment Share on other sites More sharing options...
Tom Raymond Posted October 16, 2009 Report Share Posted October 16, 2009 I'm not so sure that "good and workmanlike" is appropriate for that installation. Actually might be kind of insulting. Tom Link to comment Share on other sites More sharing options...
Carson2006 Posted October 17, 2009 Report Share Posted October 17, 2009 Mr. Katen, This is what I've found that covers "workmanlike". It may help. You may find it for free somewhere, I had to purchase my copy. It's National Electrical Contractors Association NECA 1-2000; Good Workmanship in Electrical Construction. My copy may be a bit outdated, but probably not much has changed. Maybe this might help folks. Link to comment Share on other sites More sharing options...
Jim Katen Posted October 17, 2009 Report Share Posted October 17, 2009 Mr. Katen, This is what I've found that covers "workmanlike". It may help. You may find it for free somewhere, I had to purchase my copy. It's National Electrical Contractors Association NECA 1-2000; Good Workmanship in Electrical Construction. My copy may be a bit outdated, but probably not much has changed. Maybe this might help folks. I'm familiar with that document. It's actually referenced in 110.12 as a fine print note. I'm not sure if the 2009 version is out yet or not, though as you say, I doubt that it's changed in any significant way. I'm curious to know if, as an electrician, you use that document as a standard for your work. It has some mighty picky requirements. - Jim in Oregon Link to comment Share on other sites More sharing options...
Brandon Whitmore Posted October 17, 2009 Author Report Share Posted October 17, 2009 It says, "Electrical equipment shall be installed in a neat and workmanlike manner." How the heck do you interpret that? I guess being vague has it's uses. If a code inspector see something that he knows shouldn't be allowed, but can't find a code cite for, he pulls this one out of the bag-- maybe I should start using this one. In a residential setting, nothing about exposed Romex is neat or workmanlike in my opinion...[^] (excluding what I see in your pictures) PS: If I see an electrical room with as much wire as you posted in those photos, you can bet I will be calling you in to figure it out. My brain would set itself to information overload and shut down. Link to comment Share on other sites More sharing options...
Carson2006 Posted October 18, 2009 Report Share Posted October 18, 2009 Jim, I use it as much as possible. But of course, the electrical inspector is the one to please and I haven't disappointed one yet. There really isn't a whole lot of information in this publication but what is in it is noteworthy at the least. There is a new publication out, 1-2009 I believe. $40 non-member price. Link to comment Share on other sites More sharing options...
Jim Katen Posted October 19, 2009 Report Share Posted October 19, 2009 Jim, I use it as much as possible. But of course, the electrical inspector is the one to please and I haven't disappointed one yet. There really isn't a whole lot of information in this publication but what is in it is noteworthy at the least. There is a new publication out, 1-2009 I believe. $40 non-member price. It's a fine document. The trouble I have is that the NEC is a minimum code. It's purpose is "the practical safeguarding of persons & property from hazards arising from the use of electricty." The idea is that it sets for the minimum safe requirements for an electrical installation. The NECA document goes well beyond that. It's more like an ideal that an electrical contractor should shoot for, but that isn't necessarily attainable 100% of the time, given the practical realities of a job site. If the NECA document were, indeed, the definition behind 110.12, then every single electrical installation that I've ever seen would fail to meet that standard. - Jim Katen, Oregon Link to comment Share on other sites More sharing options...
Chad Fabry Posted October 19, 2009 Report Share Posted October 19, 2009 Jim, Would you mind sending me the full size photos of the NM installation? I'd like to print them, frame them and hang them behind my desk in plain sight of folks who would like a building permit. Link to comment Share on other sites More sharing options...
Jim Katen Posted October 19, 2009 Report Share Posted October 19, 2009 Jim, Would you mind sending me the full size photos of the NM installation? I'd like to print them, frame them and hang them behind my desk in plain sight of folks who would like a building permit. I don't have full-size versions. I swiped them from Mike Holt's forum several years ago. I don't know who took them first. - Jim Katen, Oregon Link to comment Share on other sites More sharing options...
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