| Author | Message | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Well, since there seems to be a heated argument over what type of wire is good and what type is bad for an RV, and a LOT of the arguement centers around the use of THHN, both stranded and solid, and "contractor's cord", I thought I'd provide you disbelievers with some "in yer face" data. Masochist that I am, I went down to my machine shop this morning, and set my milling machine up with a 1.5" stroke on the quill. I then took a piece of #14 THHN solid wire, chucked it up in a drill chuck and the mill vice, and by moving the the quill handle up and down repeatedly, started bending the wire by an exact amount, over and over to see how many bends it took to fail the wire. IT TOOK 11 BENDS on the SOLID THHN and it broke. I tried it again, and the second time, 11. Quite consistant!! Then I put an ever-so tiny nick in the middle of a third piece, to simulate a sloppy strip job, and tried again. This time it failed in 7 bends, not surprisingly right at the nick. ................ NEXT, 14 ga STRANDED THHN (14 strands) This wire took only 12 bends and the first strand failed. At 60 bends, more than half had falied, and the whole thing broke at 98 bends. ............ OK, now for some UL1015 stranded (42 strands) Two strands failed at 110 bends. By 300 bends there a total of four failures Total failure finally occured at 460 bends .............. FINALLY, Contractors cord: For my last test, I found the CHEAPEST 14 ga contractors cord I could lay my hands on (like a $9.99/100' special at Home depot, that is now 10 years old and well used), and it had 28 strands. I stuck it in the gauntlet, and by 500 bends, not one strand had broken yet. I gave up. I also got so "in to it" that I forgot to take photos of it. My arm is very sore now, thank you. ........................... Here's the photo so you can see for yourself: http://www.heartmagic.com/00WIREstory.JPG So here are my conclusions, no longer an "opinion"... (1) IF you tie everything down and there are absolutely NO vibration or resonant points at ANY of your wiring terminations, you can probably use THHN wire of either type and get away with it. But "getting away with it" is exactly what you'll be doing... (2) In an indentical installation, solid THHN will fail a lot earlier than stranded THHN. (3) ANY USE of THHN will fail a LOT earlier than an installation that uses good quality stranded wire. (4) The "Contractor's cord arguement" can now be reduced to "quality of insulation", and I won't go there.... (5) I'm glad I used UL 1015 wire in my bus (6) It will all fail eventually.... Cheers! Gary | ||
| Geoff (64.1.0.144)
Rating: N/A |
If you don't want to talk about insulation then you finish the debate before it is done. The argument against using extension-type cable is not flexibility but that it is not designed to go behind walls where it is more likely to heat up. In other words it is rated and designed to be layed out in the open not inside hot walls. Say, when are you going to give boat cable a test on the milling machine? I bet it would do well and it IS rated to go behind walls (boat walls, at least). --Geoff '82 RTS CA | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Send me some boat cable and I'll be happy to test it. I just don't have any around! po box 675561 Rancho Santa Fe Ca 92067 I didn't want to get into the insulation aspect because there are too many variables. THHN, UL 1015, and boat wire are probably fine examples of decent insulation. So the only difference that can be argued about there is ductility of the wire itself, and I think I've settled that. As far as the contractors stuff, I'm satisfied that ductility isn't a problem. If it's only temperature you're worried about, then simply being conservative and oversizing your wires would end that debate. But it goes deeper than that... type of insulation- IE rubber vs PVC vs heavens-knows-what, the prospect of the stuff turning brittle, whether it's "softness" leaves it more vunerable to being easily cut, etc....it all depends on the type you buy and who made it (and for that matter, probably what Chinese factory it came from) and there's so many variations out there that it's a crapshoot unless you know exactly what you're buying. A big clue would be to look at what's stamped on the wire (this holds true for ANY type) if it says 85c it's probably not a good choice. If it says 105c it's probably a better choice. But I still won't go there... Now 'd like to sit back in my 1015-wired bus and watch the rest of you settle it out!!  Cheers Gary (BTW, I just couldn't stand not knowing how many bends it takes to kill that contractors' cable, so I went back at it......775..... ) | ||
| Chuck Harris - PD4104 (207.172.11.147) Rating: N/A |
Golly Gary! I'm glad you did the test, but it is not all that valid. You are flexing the living hell out of the wire in a way that doesn't simulate reality. In a real installation, vibration will be moving the wire only a small fraction of a degree. If the motion doesn't exceed the (WARNING: big engineering words ahead!) elastic deformation limit, you can bend it just about forever. The elastic deformation limit is when you bend the wire just enough so that it stays bent. In your test, you were bending the wire way too much. If you want to make your test more valid, take a 12 inch piece of wire, and attach it to your vise at one end, and pass the other end thru a small eye bolt chucked in your spindle. The wire should be horizontal. Move your spindle up and down 1/4 inch, and see how long the different wire types last. Your flexes will most probably go into the millions without any failures. (well, your MM will fail...) -Chuck | ||
| dougwoodin (24.170.175.44)
Rating: N/A |
I wired my Eagle just like Fred Hobe of North Florida Bus Conversions . I'm in the construction business, and I deal with all kinds of wire, both on the job, and off. In my opinion, Fred Hobe builds one of the finest ,most solid conversions that I have seen. The use of UL approved extention cord should not cause any problems whatsoever. The only drawback to installing this type of wire is there is no way to pull out and change anything once the wall covering is installed. Planning ahead overcomes this small drawback. The wire is all run to circut breakers, so any chance of "overheating" is pretty much eliminated. I went oversized on all circuts[12 gauge wire with 15 amp breakers] just to build in a little extra safety margin. Just my opinion. | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Hi Chuck! But of course!! I certainly understand that I deformed the wire WAY beyond what it would ever see in reality, and I never intended these demonstrations to simulate reality in any way. But you have to admit, the test gives you a very good idea of how the different types of wire will act "relative" to each other in any situation. You also have to agree that the test illustrates what happens when you nick a wire during the stripping process. What I am illustrating here is the fact that the elastic deformation limit is much different for stranded vs solid wire (ie a single large diameter conductor vs a lot of smaller diameter pieces of wire); for annealed wire (ie "softer" wire that doesn't mind being bent a lot- UL1015, Contractor's cable, etc) vs hardened wire ("hard" as in all varieties of THHN). Agreed that a "real" test would be more decisive, but it's much more difficult to set up and run than I care to do in a morning's time, and this one is good enough to illustrate the behaviours of the various wire types when subject to the same stresses, regardless that the stresses were obscenely overkill.. There's gotta be a reason why Detroit doesn't use anything but finely stranded wire in it's products. I think I've shown why, havn't I? Cheers Gary | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Thanks for all the sweat work. I think it is neat people going soooos far out of their way to figure something out themselves then sharing their labor with others. I do not think vibration per wire fracture is the only thing here. Also need to figure how good the crimp connection is and how good it will be down the road years later. I have learned the hard way that soddered connections and high amperage low voltage DO NOT necessarily mix well. Now gone on to sodderless special crimped connections with shrink heat wrap and I am very happy. Also right now the game plan is to leave the DC side of the coach alone and go 100% 120 VAC with the house side of the conversion with everything going thru one primary SW invertor and having a small auxillary SW as a backup. However, am still planning on using multi strand wire enclosed in steel conduit where needed and using sodderless crimped connections just like on a hi amperage DC circuit. Wish me luck. Thanks again for your help and I love this board. Henry of CJ | ||
| SLO (24.205.245.178)
Rating: N/A |
Whew!!!....Glad we aren't talking about hydrolics, I'd really be lost! As for my 7, I'm using stranded wire, in conduit or cable trays. When I took the luggage shelves and ceiling out of my 7, I found two distinct wiring problems. One, they ran harnesses through punched frame holes using rubber gromets at those holes. BZZZZT......Wrong......not only did the gromets move out of position for one reason or another, but in some cases actually just plain failed, probably due to heat. This caused a short on the starboard side under the ceiling panels, where the speaker and power wires ran from the center frame and ran down to the seat overhead lighting. Anyway, it was the vibration against bare steel that caused the short. Although I never even tried those lights, nor noticed if the marker light worked on that side, I can say with a fair amount of accuracy that they did not. The other problem was overheating of the wire insulation at light locations and terminals within insulated ceiling panels. So in a nutshell, coonnecters are very important, and certainly stranded wire is far superior to solid. I think as long as I ream out conduit ends to avoid any sharp surfaces and allow for wire heat at terminal locations, I should be fine wire wise........I'm still considering the solder at the crimp connectors. SLO | ||
| Mark Radius (24.247.233.200)
Rating: N/A |
I wonder if anyone has asked their INSURANCE CARRIER if they would pay on the total loss of a converted coach due to an electrical fire if they discovered that the coach was not wired to the "nationally recognized standard" (ie: the "Code"). After nearly 20 years in the fire service, my bet is that they won't. Right, wrong or otherwise, the code is the standard to which you will be held in the event of any sort of legal or insurance claim, and the insurance carriers are always looking for an "out". FWIW..... MR | ||
| Darryl (68.114.34.162) Rating: N/A |
I was an insurance adjuster for many years in a past life. I still work for an insurance company, albeit in a different capacity. There is no exclusion of coverage in any standard ISO policy for "other than Code" wiring. That's not to say they might not try to subrogate against a third party for faulty or inferior workmanship, but not an insured (first party). To go against a third party, they would have to prove negligence, which equals lawsuit. Lawsuits are expensive, and this type would require alot of "expert" testimony and preparation. I doubt you'd see an insurance company go after this one. Too much chance that they might not win. This type of suit would probably cost them $25K to $40K to try and they probably would still not win it. I know, as I was one of the litigation supervisors for our company. But, getting back to not paying a Named Insured's claim, there is no exclusion for this type negligence when done by the Named Insured. The resulting cause of loss would most likely be fire. Fire is a covered peril for an insured (first party) unless intentionally set or excluded by language in the policy body. Fire is not excluded on any standard (meaning underwritten by ISO) vehicle policy. Bottom line, this would be a covered loss. | ||
| TomNPat (68.128.42.117)
Rating: N/A |
Gary, Thanks for all the information and proof. It sure sounds logical to me, but that does not mean that it is acceptable to everyone. Scientific method versus opinion! But, fresh wild blackberry pie with butter pecan ice cream wouldn't be acceptable to everyone either. Sure is to me, though. TomNPat | ||
| Tim Christofferson (Tcmc8) (205.118.9.14)
Rating: N/A |
TomNPat, I will be over for fresh wild blackberry pie and butter pecan ice cream. I hope it is not out of season! Tim C. This is a great discussion. Very interesting. I am impressed that someone (Gary) gave us some empirical data to ruminate about (great pictures, too!). Please list some of your sources for wire. I don’t mind spending $ for quality but I still would like to find the best prices. (Anchor boat wire and UL1015). Thanks, Tim C. (MC-8) | ||
| DaveD (142.46.196.34)
Rating: N/A |
A couple of thoughts, before rejecting solid copper wire outright. (1) Romex has been used for 120 V ac wiring in recreational vehicles successfully for many years and meets code requirements. My own experience with two motor homes over 15 years is that there was no failure of the ac wiring. (2) AC receptacles and switches are designed and certified for use with solid copper wiring (such as in Romex). (3) Crimped connections with stranded wire can be subject to loosening and corrosion, particularly if a high quality crimp tool is not used. It's these loose connection that may occur which can overheat. (5) Annealed copper wire such as used inRomex is capable of withstanding a reasonable amount of bending. If wires are properly secured the amount of vibration encountered in a motor coach shouldn't result in the wire breaking. (6) The use of the proper electrical boxes, clamps , installation techniques, over current protection and safety ground provide a coordinated means of protection to limit the risk of fire or electrical shock, in normal use and in the event of a fault which might develop after installation. (7) BX armoured cable (also known as Type AC) might be a suitable alternative, provided care is taken to not nick the insulation when cutting the exterior metal sheath and the required push-in insulating bushings are used at each end. It has the advantage of providing protection against mechanical damage wherever the wiring might be exposed (such as in luggage bays). Just my 2 cents worth. DaveD | ||
| Chuck Harris - PD4104 (207.172.11.147) Rating: N/A |
Hi Gary, I would venture that the real reason that Detroit used finely stranded wire in their harnesses is to make the harnesses flexible enough so that they could be installed in the busses. Some notes that I have learned thru experience: The frame members of the bus that are subject to the most stresses and vibration are all chunks of aluminum designed to flex at amounts well less than their elastic deformation limits. If the wire is properly supported and attached to these members it will last just as long as they will. But it must be properly supported, and attached! Areas where solid wire's lack of flexibility are critical, are in places where a moving object is wired to a stationary object. Examples are the generator, the engine, the tailgate lights, ... Finely stranded wire is not the cure for all problems. It comes with some critical ones of its own. When the insulation of a finely stranded wire wears thru, individual strands of wire are first exposed to short circuit currents. They are too small to withstand the current, so they vaporize. (sometimes clearing the short!) This act frequently can cause the frayed insulation to catch fire. Solid wire presents its thermal mass and full current carrying capacity to the short. The breakers will usually trip before it gets hot enough to ignite anything. When a single strand of a stranded wire breaks, it causes the remaining wires to overload, making heat. As more strands fail, the current density increases rapidly, causing more heat, and more strands to fail. As a result, fine stranded wire fatigue failures almost always look like someone snipped the wire off cleanly, without breaking the insulation! They are often the source of very frustrating intermittants. Finely stranded wire must NEVER be used directly with screw terminals. You MUST crimp a spade lug onto the wire first! If you are worried about corrosion, dip the wire in No-ALOX, then crimp. The crimp will last forever (It would have anyway). Soldered connections are a potent problem in high current leads. You must not just stick the wire into the spade lug's crimp tube, and solder. You must first make a strong mechanical joint by crimping. Solder is much higher resistance than copper, and a joint that allows high current to pass thru the solder will heat up, and melt that solder. If you solder the spade lug onto a piece of 3-0 wire going to your starter, and don't first use a punch to crimp the connection, you will one day melt the solder out of the joint. I learned this the hard way twice, once with welding leads, and once with a starter motor that shorted. When you attach a lug to a high current lead, use a punch with a pyramid shaped end, and drive the punch, into one side (face) of the crimp tube until the wire is so firmly stuck in the crimp tube that you cannot remove it. Then solder. Your mileage may vary. -Chuck | ||
| Tom Connolly (148.78.247.10)
Rating: N/A |
Well A couple days ago and a number of posts earlier I Voiced My Opinion! "Although THHN stranded is better than solid it is still to brittle for applications that subject the wire to vibration and flexing. My personal preference is / has been SO cable / for 10 & 12ga just cut up Contractor extension cords." Since then I had to get out the handyman's favorite tool DUCT TAPE, I Put some over my mouth to keep me from saying anything here that would lead to additional debate. Now I have wrapped my head with the remainder of the roll to keep it from exploding and killing everyone within a mile of my keyboard! Before I continue let me take a moment to make the following legal statement, "The views expressed herein are only the opinions of the author, they are not intended to represent fact nor are they necessarily considered by most anything more than pure entertainment, these expressed views are not necessarily the views of the readers and are most-likely not those of the moderator." I said "Contractor Extension Cord". Maybe we shop in two different worlds, the cord I endorse and used is heavy duty! Comes in #10 and #12 gauges a green wire for ground, white for neutral and a black supply/feed wire, each of the fine twisted strand copper wires are insulated then they are wrapped wit strain relief cord and en cased in a nearly indestructible outer sheath that is able to withstand the suns heat, UV rays the rain & freezing weather, gas, oil, cars driving over it all day and the scrutiny of OSHA. It is not the $9 for 100' stuff that you light your Christmas lights up with! I think OSHA approval means that the extension cord is properly rated to facilitate the raising and lowering of heavy power tools from the roof of tall buildings. My cable ends have solid not split, heavy duty high temp terminal ends properly crimped and properly soldered, then placed under the screws on Hospital grade Devices and MIL SPEC breakers (Skycraft Surplus), If I live a hundred more years the installation is not going to fail or cause me any un-rest. If you choose to use THHN that wire goes is a conduit or raceway, If you like 12/2-WG solid copper Romex house wire you may want to consider UF the sheath is molded around all the wires and it is damp proof, and the rats will have to work harder to cause you a problem. If you are using devices that don't have these words stamped in the metal frame "Spec Grade" or if you are stuffing the wires in the spring loaded hole in the back of a device, you may as well just torch your coach now! Soldered connections Don't cause resistance/heat failures only Improperly Soldered connections do! Insurance Companies Represent their Insured, they may drop you after paying a claim that results from your negligence but they do pay the claim! Thanks Darryl for straitening everyone out! Imagine if everyone charged with negligence (ticketed) in an resulting accident was denied their claim! Chuck, A cold solder joint resulting from a bad solder job mostlikly caused your failures. If a torch was used the solder was cooked. You can relate soldering to welding a bad weld breaks, with a good weld the metal breaks and the weld lives. If your solder does not flow and bond to all the joined components you will have a failure. Soldering as simple as it may seem was a 4 month part of my 4 years of basic electronics training. Gary, Great idea with the Weller on the big lugs, obviously you, as I do, have the ability to achieve the proper temperature to flow the solder, Most think you light the headlamps up till she smokes, and probably don't even know that plumbing solder is for pipes and that electronic / electrical solders come in a smorgasbord of mixes, flux's and diameters. Fred? Coast Guard Approved may even be better than OSHA, Cause it's so good and strong you can use it in and around salt water for shore power and it will double as a tow cable in a pinch. I used it for my shore cable it has all 4 wires, feed/feed/neutral/ground, and it's Yellow so I can find it! Cord Chaffing? sure just take your knife to a CG or OSHA cord and see how hard you have to work to cut through to the wire! And that check your cord daily statement, I think maybe it's so you can find the place you drilled through or cut with your saw the last time the cord was uncoiled? Hey isn't UL the stamp of approval that goes on all those wake-up to the smell of caffeine pots that Consumer Reports about burning down homes? I second Stephen on Skycraft Surplus, East of downtown Orlando exit off I-4 @ fairbanks ave then south 100 yards on the East. Plan on staying awhile cause the have lot of great stuff! Scott, "3pt leveling vs. 4pt leveling?" 3pt has one less point! I'm gona keep the Duct Tape handy just in case! How boring it would be if we all thought alike! Good Night All, Tom C | ||
| John Biundo (Jbiundo) (67.112.121.112)
Rating: N/A |
Tom, ROTFLMAO over the duct tape remark. That's one of my favorites, too -- usually uttered while preparing to listen to the various inane sound bites coming from the (mostly) California politicians on the morning news. So... where and how do I learn how to solder? Got a book to recommend? I don't have four months, but I'm willing to begin practicing now for the wiring tasks coming up, I figure, sometime next spring. This thread has been fascinating. Nothing like a good wire debate before breakfast, eh? ;-) John | ||
| Chuck Harris - PD4104 (207.172.11.147) Rating: N/A |
Tom, This EE, and 30+ year Ham, does NOT make cold solder joints! I have been soldering properly for more than 34 years. I know a cold solder joint when I see one, I know how they happen, and I know how to avoid them. Same goes for over cooked solder joints. At one time I was certified by the DOD to make solder joints on mil spec electronic equipment. (I may still be?, but regardless, I could pass the test again with ease.) Solder is a poor electrical conductor. It is a poor mechanical connector, as well. It MUST be supplemented with a strong mechanical connection in high current applications. That means a crimp. Your "contractor grade" extension cords may be the cat's meow, or maybe not! They were not tested for this use. As I wrote earlier, I had an industrial grade cord that ran thru the center of my bus fail due to insulation that was great for flexibility when new, but hardened and cracked when 30 years old. The insulation on the ROMEX wire in my bus is as good as the day it was made. So are its conductors. The industrial cord that failed in my bus, and your contractor grade extension cords are FORBIDDEN for use inside walls by NEC. They are UL listed for TEMPORARY USE ONLY! The insulation used in ROMEX, etc are specially made for fire resistance, abraision resistance, clear code markings, high temperature (90C), and long life. And they work as advertised. 'Nuff said! -Chuck | ||
| Doug Dickinson (Dougd470) (65.161.188.11)
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Sorry - I can't leave this alone. I read Fred Hobe's article about the extension cord usage for electrical wires in a coach conversion. These cords, while attractive in many areas, are not acceptable for one big reason (acceptable to NFPA - the Electrical Code folks) - the insulationn is not designed for in-wall installation! You could de-rate the load, oversize it, or whatever and the insulation still is not going to last as long as other alternatives. Overall, extension cords "die" from cracked insulation (old age), unless earlier for damage. The modern "romex" or NM type cable is designed exactly for in-wall installation. For that reason, I will not use an extension cord for an in-wall installation. For now, I am leaning toward Fred's idea of marine cable, possibly using armor-flex cable (the appliance type with stranded wire inside) and NOT using nm type wire. I will use some sort of duct so I can replace wire if necessary or change it out if a problem occurs. My walls will not be accessable. My $0.02 worth Doug St Louis, '83 MC9 | ||
| Tom Connolly (148.78.247.10)
Rating: N/A |
Hi Chuck, So if solder is made of tin & lead and on the list of metal properties pertaining to conductivity and resistivity both metals rank highly conductive with little resistance, almost as good as copper but not as good as gold and certainly less expensive, Why then do the lead ends on battery cables and the terminal posts not melt? maybe if you are sticking a conductor in a huge terminal end add filling gluing it in with solder a problem would arise buy I think no problem when matching the size properly, additionally I prefer proper fit, crimped and soldered. Actually it is more likely that NEC forbids the use of Romex for use as an extension cord than an extension cord as a permanent conductor, Romex is not insulated well enough to be handled by the consumer when energized, the outer sheath peals off on the first thin it catches on. Good extension cords are designed for consumer safety and extreme use! I've pulled a million feet of Romex through buildings and the jacket is anything but abrasion resistant, I would have to get the book down and dust it off to be sure but, if memory serves me standard Romex is type NM and rated at 60C, THHN is abrasion resistant ( has a clear skin over the hard insulation and has better dielectric properties) THHN is rated at 90C. Again if using Romex, Type UF is a better choice! There was a reason your cord failed and I don't know what that reason is, but I suspect it did not fail because it was an extension cord! Tom C | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Tom, while I agree with you on virtually everything you said, you just nailed yerself with one that nabbed me cold a few years ago...so don't feel bad... the conductivity of gold is much worse than copper!! Since getting busted on that myself years ago, I've always been surprised and amused at how many EE's think Gold's the best. Its simply the most difficult to corrode, so it get plated on everything, but as a conductor it kinda sucks... Here's the order of good some conductors: (Relative conductivity, at 20l degrees C, based on copper as 100) Silver 106 Copper (Annealed-soft) 100 Copper (Hard drawn as in THHN!!) 89.5 (oops, another nail in the THHN coffin!) Gold 65 Alumimum 50 steel 3-15 Tin 13 Nickel 12 Lead 7 ...The reason lead ends on cable do not melt is that they are gigantic and equivalent to giant size wires. And they do melt- you oughta've seen the terminals on a couple of my T106's- I bought them super cheap and almost new from a guy who'd used them once on an electric car and melted the terminals on the first run. He wasn't aware that you could have new ones melted back on for a song at the battery place.... ...and I'd guess that the reason the insulation on Chucks cords degraded was probably that they were old and made of rubber, not "modern" thermoplastic like PVC. That old rubber stuff hardens and rots. The newer cords made of PVC and similar plastics does not. John, learning how to solder is fairly easy but it's better if you can actually have someone who "knows" show you. Here's two articles that may help- the principles are all the same be it a big or small joint http://www.epemag.wimborne.co.uk/solderfaq.htm http://www.allsands.com/HowTo/howtosolder_cc_gn.htm ...and Doug, telling us that "it wasn't designed for...blah blah..." is not good enough. Not even close. TONS of stuff we use in our RV's, from appliances to insulation wasn't "designed" for RV use. I wish everyone would get off that particular arguement. Let's see.... how about "Coaches and school buses weren't designed to be converted into RV's"... can we go from there?.... Oh My...what ARE we all doing? Cheers Gary | ||
| Doug Dickinson (Dougd470) (65.161.188.11)
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Cheers Gary and all While I fully agree with the idea of us not being bound by the ordinary use of any item, the issue here is WHY it is not rated for the use. Marine cable is not rated for RVs, but I would use it in a heartbeat. The WHY is that extension cords are not universally (sp?) constructed the same and therefore are not rated for the use. (This is per a call to NFPA - I am a member) Rubber insulation decays in air, and PVC insulation is prone to UV and other deterioration. Both would work for extension cords, but not for in-wall construction. That doesn't even account for things like derating or over-sizing. I don't know why marine cable is not rated for RVs. I will investigate further before I decide what route to take. Anyway - to each their own. We do what works for US - and learn from discussions like this. One of the attractions of this hobby is to learn and try new and different things - otherwise it wouldn't be as much fun (to me at least). Also - you are right about gold as a conductor. I had my chops busted by an employee over that very thing. Gold is usually used to have a corrosion-free connection. (BTW - most coaches ARE designed to be converted - that's why they sell brand new shells for the purpose! Look at Prevost, MCI, Bluebird, etc).... but that's another thread... :-). Doug St Louis '83 MC9 | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Mee too Doug!! Like boat wire, I'm sure UL 1015 isn't RV-rated either but I love the stuff for my bus. The contractor's cord thing is a toughie. Fred Hobe uses it and his conversions are top notch from what I hear. That in itself is testament enought to me that If I didnt' have a giant pile of 1015 already laying around, I'd probably use it as my next choice. But the problem as I see it is that there are so many brands and consequently so many qualities of the stuff out there, that unless you were to ask Fred specifically what brand he uses and where to get it, using the stuff availiable at your favorite local hardware store is nothing more than a giant crapshoot. Oh yeah...oops.. Something about this board occasionally intreprets characters I type as (other than letters and numbers) as weird things. I just noticed that my conductivity chart says at 201 degrees C.. it's 20 not 201! Cheers Gary | ||
| Tom Connolly (148.78.247.10)
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Gary, I really knew that, I didn't think anyone would really use gold wire, actually I didn't think I would get caught, We must be using the same reference. http://www.amm.com/index2.htm?/ref/conduct.HTM Can I recant and go with gold plated silver wire for conductivity and resistance to corrosion? Tom | ||
| Doug Dickinson (Dougd470) (206.71.103.89)
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And for the radio folks out there - The new PCS base stations you are seeing pop up all the time have silver substrate PC boards, silver (plated) shields, and some silver wire in them. at 1.9 GHz, you can't fool around with even the slightest resistance much less corrosion on a connection. Connections are frequently gold plated. Now, that is a level that I don't think my coach will be seeing. FWIW | ||
| Richard Bowyer (Drivingmisslazy) (66.190.119.82)
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Doug, do you know what marine cable is actually rated for? I have never been able to find any specs or criteria, so I am not as firm a believer in boat cable as most people seem to be. Richard | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
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>>Can I recant and go with gold plated silver wire for conductivity and resistance to corrosion?<< Tom, it's a deal!! If you can find the stuff and send me a bunch, I'll be happy to see how many times I can bend it before it breaks. Then can I keep it?? Gary | ||
| Geoff (64.1.0.44) Rating: N/A |
Richard Here is a start on boat cable specs: http://www.ancorproducts.com/abyc.html --Geoff | ||
| Chuck Harris - PD4104 (207.172.11.147) Rating: N/A |
Hey Gary, Where are you getting the idea that ROMEX is hard drawn copper? It isn't, it is soft annealed copper. If you want an example of hard drawn copper wire, check out the center conductor of your cable tv cable (RG59, or RG6, or Quad 6). Then compare it to the copper wire used for your telephone. Same gage (+/-) vastly different stiffness. If ROMEX, etal was hard drawn, you wouldn't be able to bend it to get it into the box. Also Tom, I haven't been able to buy 60C ROMEX around here for 30 years! It is all 90C. The code still recognizes the old 60C stuff, but to use it in insulated areas, etc, it must be derated (eg. 15A for #12). -Chuck | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
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Hmmmm did say that? I don't remember mentioning romex in my rants.... ;) THHN is the one I'm growling about mostly. It's very hard stuff. It's my perception that romex is definitely drawn harder than "annealed" but I'll agree for now that neither romex or THHN are as hard as it is possible to make them. I'll see if I can find some specs on either. The bottom line for me still is the fact that they are solid, or at least very few strands as compared to similar gauged boat or UL1015 wire. Hard or not, my personal preferences tell me that neither type should be in a bus. (although I've admitted to using 8ga thhn for my Genset's power feed, so I guess I'm somewhat a pot calling the kettle black !! | ||
| Tom Connolly (148.78.247.10)
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"If you want an example of hard drawn copper wire, check out the center conductor of your cable TV cable (RG59, or RG6, or Quad 6). Then compare it to the copper wire used for your telephone. Same gage (+/-) vastly different stiffness." Chuck, That would be a bad example. The center conductor of the 75 ohm coax your referring to comes in 2 flavors, soft as a wet noodle solid copper and copper clad (copper plated steel), almost all the wire used for cable and TV antennas use the Copper clad because its cheaper. Solid copper is used in over 100 ft runs on Satellite as the center conductor is carrying a control voltage, and the voltage drop in excessive cable lengths causes a switching voltage problem. For normal RF TV use the center conductor serves as a guide for the signal passing through the cable as it is really circling the center conductor and traveling through the Dielectric that surrounds the center wire, the copper coating on the steel keeps the steel from rusting and insures a non corroded connection,the foil and the braid shield frequencies from entering or leaving the cable and supply a continuity path. Tom | ||
| Chuck Harris - PD4104 (207.172.11.147) Rating: N/A |
Tom, I really blew that one! RG59, and RG6 have always been copper clad steel. Whoops! As to whether copper wire used in house wiring is hard drawn, or soft annealed, I had to back my way into the standards for that proof. According to "ITT Reference Data for Radio Engineers": At 20 C (68F), #12 soft annealed copper is: 1.588 ohms/1000 ft. #12 hard drawn copper is: 1.652 ohms/1000 ft. They claim that copper wire's resistance increases about 0.004 times every degree C rise. According to NEC: #12 copper @75C is 1.93 ohms/1000 ft. The two tables give their info at different temperatures. 20 C and 75 C! So we must compensate in order to make a comparison. There is a temp rise of 55 C between the ITT, and the NEC tables. So the resistance should increase by 0.004 x 55 = 0.22 times. (Note, increase BY, not increase TO!) 1.588 ohms x 1.22 = 1.937 ohm/1000ft 1.652 ohms x 1.22 = 2.015 ohm/1000ft Since NEC says the resistance is 1.93 ohms/1000ft, I conclude that the wire the NEC tables applies to is SOFT ANNEALED COPPER. Gary, THHN is just an insulation. The conductors in a THHN cable could be hair fine, or solid, or aluminum.... (NEC has expressed a preference for solid, or heavy stranded in building wiring.) ROMEX is just a style of cable. It comes,(has come) in all sorts of insulations ranging from the modern THHN, to older cambric, and asbestos. -Chuck | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
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Yup Chuck you're right! THHN actually refers to "Heat resistant PVC with an oil and gasoline resistant nylon jacket", per UL 83 standard. But in the context of this amazingly enlightening discussion, I hope we can agree that we're simply talking about the wire everyone buys from Home Depot or the electrical contractor's supply... kinda like saying "kleenex" or "xerox"... (hmmm, then why didn't they name it "thhn-ex") ...and I will admit "uncle" too... so far all the THHN building wiring I've found reference to is dead soft annealed. So I will stand corrected on that one although the thickness of conductors found in average THHN (if there is such thing) still makes it break under repeated stresses a lot more easily and faster than wire made of many, finer strands...and that's been my point all along... Cheers! Gary ...tag... | ||
| Chuck Harris - PD4104 (207.172.11.147) Rating: N/A |
Gary, Yes, you are absolutely correct! The solid wire cables are very much more likely to stress fatigue, and break, when subject to repeated bending (past the point of elastic deformation). No question. No argument. None at all! And yes, we are talking about the common available in Home Despot style house wiring (Romex, THHN, ...) But, sometimes "good enough" bests "best". There are ample examples of busses house wired with romex that have successfully and safely weathered years and years of use. There are also ample examples of insulation failures when using inappropriate "extension cord" style cables. Even I had an experience with this failure. Side by side, in my bus that was converted in 1970, the romex worked (and works), and the industrial quality power cord, failed.... Insulation failed, not the stranded copper wire. I suspect that the marine cable is good stuff. It is designed to get wet, get UV, get oil soaked, get abraded, and still function. It bothers me that it is not recognized for use in RVs and houses. The engineer in me has some suspicions, but no real answers to that puzzle. -Chuck | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
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Gimmineeee, an agreement!! wow!! And I agree that there are many sucessful installations of all kinds of wiring. If installed "properly" whatever that is, most anything will probably survive- probably even zip cord if you made it three times overrated and stuck it in conduit (well, I guess maybe not...) So now is it simply a matter of how various types of wire survive "improper" installations and for how long....?? And the boat cable is probably not in the RV code 'cause it's too expensive... the stick 'n' staple industry surely wouldn't want to back themselves into a less profitable corner, would they? heehee Cheers Gary | ||
| FAST FRED (209.26.115.18) Rating: N/A |
For those that need better than Boat Cable , the good folks at Skycraft Surpluss frequently have used NASA wire which IS SILVER coated. Much of their's is 30 or so wires in a tough cable setup Some are really heavy , many are only for controll circuits. Skycraft also sells good terminal ends , by the pound! Gary S. your samples of boat wire and cable are on the way! FAST FRED | ||
| Doug Dickinson (Dougd470) (206.71.103.89)
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Fred We, in the mid-west, are lacking for the kind of marinas and accessibility you have on the coast. Do you have other sources of supply for marine wire/cable that us dry-landers can check into? Thanks | ||
| FAST FRED (209.26.115.99) Rating: N/A |
West marine in CA has an 800# Defender Industries does too, Hamilton Marine in RI has 800#, all will send a free catalog . 800 info is free at 1-800-555-1212 Unfortunatly NONE of these places are really cheap , but in purchasing small quantities , the savings of not having left overs will make up for it. FAST FRED | ||
| Doug Dickinson (Dougd470) (65.161.188.11)
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Thanks Fred |