| Author | Message | ||
| bill chisholm (Billybandman)
Rating: N/A |
Isit OK to put 120vac,12vdc,and coax together in same conduit. Which ones can go together, and vice versa? | ||
| jimmci9 #2 Rating: N/A |
different voltages need to be "shielded" from 1 another....or you'll get "bleed".... | ||
| Gary McFarland (Gearheadgary)
Rating: N/A |
the AC and the DC won't bother each other, but the AC may bother the coax. It's nice to have everything in it's own pipe, but not typically practical. gary | ||
| Marc Bourget Rating: N/A |
The NEC allows it, to a limited extent, but all units have to have the same (highest) volt rated insulation. So, if you run 600V THHN, for the 120VAC you'd have to run the same insulation value, like THHN, for the 24 VDC. They don't make Coax with 600V rated insulation but you'd want to do something else because of the noise it will pick up thru induction. If you want a NEC reference I'll dig it out! Onward and Upward | ||
| Jim-Bob (Pd41044039)
Rating: N/A |
As a practical matter you should never run all of these in the same box/conduit. A service tech working on 12 volts is going to be pretty upset or maybe injured when he gets into 240 volts. If there is a short or fire, the 12 volt or control wires may become energized with the A.C. voltage. (By the way, this will fry anything connected to the coax or 12 volt wiring.) Sometimes there is no practical alternative, like in the genset connection box, and in those cases, the systems should be separated as far as possible. Jim-Bob | ||
| bill chisholm (Billybandman)
Rating: N/A |
Thanks for the input guys. | ||
| John that newguy Rating: N/A |
The telephone company places telephone wires in the same underground conduit as the AC service and Cable TV. They've been doing that for years and it's always met code. Many TV/Phone and AC outlet boxes are combined units, with all feeds connected inside the same box. Most surge protectors are equipped to serve TV, cable, phone and AC service.... all in the same unit. The cable (tv) is shielded, the phone is twisted pair and AC inductance is usually well filtered out. Although I might "feel better" running it separate, but there's no need to. I plan to use the same conduit, as most RVs do. | ||
| R.C.Bishop
Rating: N/A |
George Myers....where are you?.....I think your Designing Electrical Layouts For Coach Conversion says its 180 degrees from what's posted here.....which is the way I did it....?????...or? Thanx< RCB '64 CROWN SUPERCOACH (HWC) | ||
| John that newguy Rating: N/A |
As a side note... The size of the conduit would concern me. The conduit I would use would be of sufficient diameter to very easily pull many various cables through. 2" PVC would do OK, larger would be better. If it were a small diameter (1" or less), I would use two, one for the ac and the other, for everything else. | ||
| Dave and Mel Rating: N/A |
In Oregon, TV, Phone and AC have their own conduit entering the house, as well as their own termination boxes. Then one wire each is run to a media panel if the homeowner wants one. As a rule, low-voltage and AC are not run through the same drilled holes. There is also some concern about interference caused by the AC. 2002 NEC article 800.52 may help concerning separation from other conductors. Good luck! | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Much as everyone will probably have a great time yelling at me, I did it. My 12 and 120 are in quite a few common conduits. I always use 600v rated wire for both, and color code the heck out of things so I won't get anything confused. Also I run 10ga for all my 12v stuff and 14 ga for the 120 volt stuff, yet another way to ID things. Also I made sure there is enough room and the wire gauge is sufficient that there are no heating issues. It's not everywhere in the bus because the bus is mostly 12 volts, but in the places where both voltages needed to be I just did it. Again, I totally understand and acknowledge the safety issues it "could" cause, but it's my bus and I did it my way, so "there"..... and I use the bus frame for 12v common for everything. Not a hint of problem and I've got a lot of electronics stuff working quite happily. this oughta stir up all ya hornets.....  | ||
| FAST FRED Rating: N/A |
Since you know of the danger , either dont risk it , Or just KILL the AC while worlking on Any electric wiring. Your way, FAST FRED | ||
| John that neguy Rating: N/A |
And here I was assuming that the AC would be romex, not single, uncased wire.... No biggie, but with romex, there's absolutely no chance of confusion of conductors. We had a (new) gal Tele worker cut into a BIG voltage power line that was run in the same trench (as they usually are)... She lived (miraculously), but did suffer some serious problems. Both cables are in the standard black casing and not clearly marked in any easily discernable manner. That one fed the business she was trying to repair the tele cable for. I have worked in many, many business locations where the uncased AC, telephone, TV, and audio feeds shared all the same conduits and troths (both interior and exterior). No big deal; no code violations, just be careful. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Well we've been thru this long ago and with lengthy discussion, but Fred and I'd NEVER use romex, it's solid conductor. Fred likes boat wire and I agree it's good stuff. I use finely stranded individual conductors. But not romex unless it's boat romex that's finely stranded and soft annealed. In my book, "Finely stranded" is the right stuff. THHN stranded is not enough strands. Boat wire is a lot more conductors of more finely stranded stuff. THHN is hardened, regardless of if it's stranded or not, and ...whoopeee...here go the arguements again.... I personally don't think it's right for a bus. If solid wire or THHN as applicable for a bus you'd see manufacturers using the stuff (and I'm talking about the REAL guys, not the stick 'n staple cheepos) but you don't. Real bus manufacturers, like truck and automakers, use finely stranded wire everywhere, and for good reason. That said, if you use solid or any flavor of THNN it will probably work fine for a long time if you bolt it down well. And if it fails, it will probably do no more harm than make a circuit stop working, and cause you mucho grief finding the break. Lots of people including stick and staple builders use the stuff, because it's cheap, avaliable, and fast to use. That don't mean it's correct....but it don't mean you're gonna get killed using it either.... Arguements restarted... have fun with this one!!!! | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
Several persons have noted the possibility of picking up stray signals thru the coax cable, and I strongly disagree with those statements. The purpose of using coax and the way it is constructed eliminates any possibility of stray signal pickup. That is assuming that it is properly terminated on each end. I base this statement on my prior experience of installing large radar and communications centers throughout the country for the USAF. We had cable trenches stretching sometimes hundreds of feet with three phase AC power, telephone cable and coaxial signal cables all side by side and sometimes twisted together. In making all the dozens of runs we never paid any attention to which cable was on top or bottom or side by side. Richard | ||
| bill chisholm (Billybandman)
Rating: N/A |
Now I am really confused. | ||
| Marc Bourget Rating: N/A |
Richard, I don't doubt your experience, but the point remains that there's no Co-ax with, for instance, 600V rated insulation. Assuming that a damage situation resulted from the use of underrated co-ax, and, due to the failure to follow the NEC, your insurance company could except its obligation to insure the loss, is it really worth combining the "three"? Mind you, I pose these points as assumptions in order to invite your discussion. I've seen insurance companies ignore possible defenses to payment on occasion. Onward and Upward | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
I really do not remember the voltage rating of coaxial cable, so I can not comment. Maybe I will do a search and try and find the ratings for RG-59 or one of the other ratings that we used. I also question the need for utilizing 600 volt rated wire. It is definitely a significant overkill in my opinion. Richard | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Mark, sorry, there is lots of coax with 600 volt rated insulation. And practically speaking, as long as your AC wires are properly rated, it doesnt make a bit of difference what the coax might be rated at. There's no law or rule that says just because one wire in a bundle has high voltage on it that all the remaining wires in theat bundle must also have the same rating. It's just not done in industry. For example, take x-ray equipment... I know we're not talking about busses here BUT in a harness to an x-ray head, two wires will have 20-30KV insulation and the rest will have 200,400,600 volt (etc) insulation, and a darned lot of data lines might well have less. You NEVER see something like that with all wires requiring kilovolt insulation. Likewise on a bus. Good enough, and well good enough at that, would be using AC wiring with 300 volt insulation right along with any other type of wire you want to use regardless of it's rating, as long as it's rating is adaquate for what it's carrying. Last, as far as "damage", if 12 volt, coax, and 120 volt wiring were all in one conduit and that conduit got damaged badly enough to cause them to short together, well I'd guess you have worse problems at that point to worry about, like what you're going to do with the truck that just rammed your bus, etc. Ok, so a small mouse got in your pipe and ate the insulation. Well, your conduit is grounded, nicht war? It'll just cause your breaker to snap and possibly a few things to burn out. But then 600 volt insulation on everything wouldn't have changed anything excpet fed the mouse a bit more... In the end, there is a lot of armchair engineering going on here, and then there is what works and what works well. Usually two different things... all in a grin... | ||
| John that newguy Rating: N/A |
Awwwwww....... you guys can be pains.... From Here: http://ceenews.com/mag/electric_technology_wiring_nec_2/ "The Code consists of an introduction and nine chapters, divided as follows: General rules. The Introduction and Chapters 1 through 4 apply to all electrical installations, including low-voltage or limited-energy wiring (i.e., what I refer to as technology wiring) discussed in Chapters 6 and 7. Special rules. Chapters 5 through 7 apply to special occupancies, equipment or conditions. It is important to note that the requirements noted in Chapters 5, 6 or 7 could modify the requirements noted in Chapters 1 through 4. For example, Sec. 300-3(c)(1) permits conductors of circuits rated 600V nominal (or less), AC circuits and DC circuits to occupy the same equipment wiring enclosure or raceway, if all conductors have an insulation rating equal to the maximum circuit voltage applied to any conductor. However, Sec. 725-3 states that Sec. 300-3(c)(1) does not apply to Class 2 and 3 wiring. Therefore, the NEC does not permit Class 2 and 3 wiring with power conductors because of the requirements set forth in Sec. 725-54(a)(1). Communications systems. Chapter 8 contains the requirements for communication circuits, such as telephones, satellite dishes, TV antennas, Cat. 5 and broadband systems. The requirements within Chapter 8 are independent of the requirements contained in Chapters 1 through 7 — unless a specific reference in Chapter 8 is made to a requirement in those earlier chapters. Tables. Chapter 9 consists of tables used for sizing raceway, calculating conductor fill and determining limited-energy systems. Code enforcement. Although the NEC is purely advisory, it is intended to be adopted by governmental bodies and other inspection departments. However, it is up to these bodies (states, counties, cities, etc.) to adopt the NEC as a legal requirement for electrical installations." So, there ya' have it. No "600 volt" insulation requirement. All services can be run in the same conduit No-one's committed to doing anything "NEC" or not. And Romex will suffice if it's allowed to move in the cavity it's routed through. If you secure it to walls, etc, the flexing of the walls may eat through the romex insulation over time. It -has- happened to me in both a Winnegargbage and the "Georgie-Boy". Both cases, the romex was stapled to walls and routed under walls. Inferior installations will cause problems. The stranded wire is actually less expensive, especially for a manufacturer, since it can be bought in bulk and used for numerous electrical tasks. It can and does, add to confusion of wiring schemes. Where the finished unit will be used by individuals of varied skill, keeping it "plain and simple" may be the RV manufacturer's credo to avoid litigation. There. I am done. | ||
| Macgyver (91flyer)
Rating: N/A |
I have to pipe up on this conversation... I have to agree. Running AC, DC and coax in the same space is acceptable... The ONLY time I've ever seen a problem is when the DC wires were actually DATA cables, such as unshielded CAT-5, or a computer harness of some kind. The DC signals in these types of cables are VERY sensitive to induction, but not if they're shielded.... Personally? I plan to run unshielded CAT-5 for my computer hookups, but NOT in the same running space as the A/C power. At least 4 foot away from any A/C source is the standard we use when pulling unshielded CAT-5 cable. You also have to be VERY careful about flourescent ballasts, as they are notorious for destroying the signals in unshielded DC cabling, and introducing spikes into ordinary DC cabling. But, again... If the coax is properly grounded/terminated at each end of the cable... then the coax shouldn't be susceptable to the interference... the "shielding" on any of these cables is actually a farraday cage, which virtually ELIMINATES R/F interference from entering along the LENGTH of the cable... That's not to say that it won't or can't enter into the cable from the ends if they aren't properly shielded as well. Have fun. -Kevin | ||
| Marc Bourget Rating: N/A |
I didn't mean to say that 600V insulation had to be used, just that the NEC said it had to be equal, the 600v was an example. Extrapolating from this, I was informed that there was no co-ax generally available with 600v insulation. Once again a code simply establishes a minimal duty of care, real life situtations are too varied for a code to establish a guarantee. Gary, my interpretation of all wires having the same insulation value is to prevent introduction of a "weakest link" in the mix in a conduit. I'm no journeyman or EE on this and simply defer to common sense understandings. While I have been accused of being a "know it all" I'm not, lots of times I'll ask a question or make a comment simply to expand the coverage of a thread, not do shove my thoughts down the "mental throats" of other. Thanks for your add'l info. | ||
| Jtng Rating: N/A |
Gee Marc... don't be so acey. (giggle) | ||
| FAST FRED Rating: N/A |
When selecting wire TINNED conductors and properly crimped terminal ends makes the most sense in terms of long term performance. Which usually leaves us at Boat Wire . Circuits with #10 two strand (with DC colors) and #10 3 strand (with AC colors) and the wiring and voltage drop hassles are GONE! Works for me, KISS FAST FRED | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
There is romex available with THHN stranded wire inside the outer cover. I have some on my coach. It is not at Home Depot though. | ||
| Pat Bartlett (Muddog16)
Rating: N/A |
No one mentioned derating the current carring conductors based on the number of conductors in the conduit. | ||
| Henry R. Bergman, Jr. (Henryofcj)
Rating: N/A |
I would be more comfortable running separate conduits for EACH type of cable. Just the way I would do it. Thanks. |