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About oldjohnt

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  1. Great, that's EXACTLY the way I would do it also.........Good to hear, thanks Jack Also good to hear, as I noted so long as the source is self limiting and provided the ampacity of the wiring from the panels to the controller meets or exceeds the maximum possible output AS IT INDEED SHOULD BE ANYWAY alls well. Also one needs to take voltage drop into the equation which might call for even BIGGER wiring then required for ampacity only. Thanks Lou John T PS I figured most would already be aware of this.
  2. One thing that may be slipping by some readers regarding solar disconnect methods and/or overcurrent protection is WHERE THE DEVICE IS LOCATED. Sure it would be convenient to install such disconnects and/or overcurrent protection near the charge controller and could include BOTH the Input FROM the panels PLUS the Output TO the batteries, and I'm sure its been done and "works" to isolate and disconnect solar from the charge controller and charge controller to batteries. HOWEVER while this serves fine as a disconnect, it DOES NOT serve to protect against shorts in the "wires" FROM the batteries TO controller orrrrrrrrrrrrrrr FROM the solar panels TO the controller, and an unprotected short there can cause high current and high heat and perhaps a fire. Ideally the "overcurrent protection device" is located AT THE ENERGY SOURCE such that a short in the wires BETWEEN the source and load is protected. Obviously a breaker at the charge controller DOES NOT protect against a short and possible high heat and a fire hazard between the panels or batteries TO the controller. NOTE in the event the panels themselves or the combiner box has overcurrent protection and/or the energy and current (thinking solar panels now) is to an extent self limiting such that the max current cant exceed the wires ampacity, there's not much of a problem FROM panels TO the controller. So l HOWEVER Its more the batteries I'm thinking of now which have a tremendous current capacity and its there that overcurrent protection (for wires TO controller) is EXTREMELY IMPORTANT to be at the batteries and NOT way up at the charge controller. So long as the wires ampacity from panels down to controller is equal to or greater then the max the panels can produce all is well AND THEY SHOULD ALREADY BE AS SUCH.......... I doubt anyone would disagree over current protection FROM the huge battery bank TO loads such as the RV distribution panel or devices or controller is necessary. Of course one can have BOTH overcurrent protection at the batteries to protect the wire FROM batteries TO controller PLUS still have a convenient disconnect method right at the controller. That way theres adequate protection plus a handy disconnect. NOTE this is NOT to tell anyone how to do anything nor define the risk or how likely it is or isnt.......Its ONLY to explain to ones who may not understand how in order to protect against excess current and possible heat in wires FROM the energy source (batteries) TO loads or devices or charge controllers etc etc THE OVERCURRENT PROTECTION MUST BE LOCATED AT THE SOURCE THE BEGINNING AND NOTTTTTTTTTTTTTT later downstream where it doesn't know or see or measure NOR can protect what happens before it.. PLUS the overcurrent protection obviously needs to be rated to match the wires ampacity NOT larger... Hope this helps, I try my best. Likely most already are well aware of all this and have proper overcurrent protection installed but just in case no harm in pointing it out.... John T
  3. JT and Yarome, as far as I'm concerned REGARDLESS if the NEC applies to some part of RV wiring or if it doesn't WHY TAKE A CHANCE AND RISK A FIRE OR YOUR LIFE?????. Following the NEC can prevent a fire or save a life and its even MORE IMPORTANT in an RV with all that light wood and paneling and combustibles in a tight perhaps poorly wired living and sleeping space. I don't understand why people would argue against "reasonable" safety wiring or procedures under the thinking OH ITS SUCH A LOW RISK its unlikely anything will happen, ESPECIALLY if its so easily preventable. But as I always say to each their own, choose your own risk tolerance and make YOUR choices.......... John T Retired and sure over safety minded electrical engineer but I've seen, studied and understand the risks, my life's work just made me that way LOL........... NOT a solar expert however
  4. WOW JT that's one SERIOUS system. Indeed, high voltage arrays allow for less current (voltage drop and wire size issues) from panels to controller and I'm unsure if you can get one to suit your installation, but I used to specify "shunt trip" I believe circuit breakers so you could push a remote button, say in the RV, to open the up on the roof breaker............Of course, a pure manual safety (can get fused or unfused) switch in an easy to get to convenient location is another option. I'm sure your already aware that overcurrent protection is required AT THE ENERGY SOURCE not down at the load in order to properly protect the feeders as overcurrent protection downstream does not help the wire FROM the source TO the load, even if it (or an RV main panel) has its own protection. YOU DO NICE WORK Geeeeeeeee Yarome I bet you're more current on the NEC then myself, I hope I don't have to dust off my old code book and study up on your suggestions, I'm on vacation at tractor shows now lol John T
  5. Similar to Chad, I have a circuit breaker between my solar panels and charge controller and Id do that regardless if it were required or not. However that's NOT any expensive or complicated method, a simple ON or OFF. To your specific question: NO I cant think of a reason why you should NOT have one, but my background is in electrical power distribution (where the wires must be protected by an overcurrent protection device matched with the wires ampacity (NOT higher rated) so excess current cant flow that might melt the insulation) NOT solar, so no warranty. AS always, its your rig your money and your risk (be it big or small) so look at the costs and benefits and risks involved then make an informed decision to suit your needs. John T
  6. Todays mechanics rely on a computer to tell them whats wrong, so computer said replace all the wiring...lol Jim, it appears NONE of the mechanics bothered to even look under the dash where I told them it smoked when I plugged into one of the 12 volt outlets, ALL they did was plug to the OBD port. The little shop owner DID look under and saw the burned wire and repaired it in 15 mins. The OBD said cant communicate when I plugged my cheap reader in. A huge dealer and a huge GM dealership BOTH said it needed computer and harness etc YEAH RIGHT LOL Nice chattin with you John T
  7. JT thanks for the feedback that's appreciated. Those darn connection problems I experienced at our huge naval industrial facility were due to temp differences and expansion and contraction so obviously the outdoor electricals were the most problematic. That's why I instructed mush more inspection and maintenance there versus our heated buildings. A good regular scheduled visual inspection and tightening as/if required can prevent so many problems ESPECIALLY in outdoor installations. Keep em tight lol Best wishes, yall keep electrically safe now John T
  8. Good points Dutch, Sure as one who practiced power distribution much of his life and studied and used the NEC faithfully, I tend to be extra safe when it comes to life safety ESPCEIALLY when a hazardous situation is so easily preventable. At least after all this exercise (Thanks to you and all for their help) many who didnt even understand the NEC and overcurrent protection can see why using 30 amp rated wire in a 50 amp feeder from the pedestal to the RV main panel IS A HAZARD (albeit yes small risk) and why the use of 30 amp wire protected by a much larger 50 amp breaker violates the very essence of the NEC's overcurrent protection. In my years of practice and study I just saw toooooooooooooooo many examples where a life was lost or a fire occurred because someone thought OH THE RISK IS SMALL or what does the NEC know lol I'm smarter then they are AND IT GOT THEM KILLED !!!!!!!!!!!!!!!! Its those small unforeseen risks that start fires or get one electrocuted in so many cases I AGREE 100% the risk is in the cord BUT that's what's laying in water or on the ground or on sharp rocks and gets run over or kids step on YIKES But that's the very reason the NEC theory of overcurrent protection is there so there cant be enough current to overheat and melt the insulation (Still NOT a dead short to trip the 50 amp breaker) so a hot live wire can be exposed to water or earth or the RV. If it were a proper 30 amp breaker there cant be enough current to ruin the insulation cuz it can pass 30 without damaging it. SUMMARY why take a life risk even if its small while its easily preventable?????????????????? I prefer to err on the side of safety myself but if a person is willing to take that small risk they may end up paying the ultimate price IS IT REALLY WORTH IT ask yourself, IS IT ????????????????????????????????????? That's the reason I have to go on record as pleading with people to NOT take that risk,,,,,,,,,,,,I have to go on record as educating and explaining the risk to non sparkies,,,,,,,,,,,,,,,,,,,,,,And even though I'm a poor teacher and cant explain power distribution and overcurrent protection (BUT who can do that lol) to non electrical power distribution gents HEY I TRIED GIVE ME THAT Use what you please, take what risks you're willing to take YES ITS SMALL but think twice before using 30 amp rated wire in a 50 amp circuit to your RV I BEG EVERYONE NOTTTTTTTTTTTTTT TO DO THAT that small risk may cost you dearly !!!! THANKS SO MUCH DUTCH you took the time to understand and help and provided great insight and I respect your and anyones right to do as you please and take what risks you like and I expect in return my right to try and help and educate the fine gents here and explain the risks and the NEC and overcurrent protection IF IT SAVES ONE LIFE OR PREVENTS A FIRE IM GLAD TO DO IT and thanks to all who participated and asked good valid questions I tried my best to answer. CAN WE ALL AGREE THE RISK IS SMALL I (0ne who spent much of his life in the electrical and NEC and safety areas) think it is and I'm no longer willing to take it but others sure are........ God bless all and keep safe now, hear me do NOT do as I suggest, consult the NEC it can save your life THANKS to all who took part in this fun and educational discussion. As gentlemen and professionals we can agree to disagree John T
  9. Its no surprise to me so called competent service techs couldn't find a problem lol. A while back I took a car to a huge reputable NON GM dealer who had the car a week with several techs working on it and they couldn't fix it but said the computer was bad............Next I take it to one of the largest GM dealers in Florida who told me I needed a whole new wiring harness under the dahs and it would cost $1500 to repair it............................SOOOOOOOO I dropped it off at a mechanic who lived in a house trailer and had a carport where he worked on cars,,,,,,,,,,,,,,,,I drove by 30 mins later and the car was repaired and was running perfect and he charged my $40, a wire under the daSH had overheated and melted insulation and shorted so he repaired and repacked and fixed the blown fuse........ Moral of story KISS keep it simple stupid and get back to basics and systematic troubleshooting which so often in RV and trailer and connector wiring a 12 volt test light can help find the problem I'm ONLY saying what worked for me and what happened above and it may well not hold true for others or other vehicles, I'm here to help NOT bicker..........My experience may well be different from others. If trailer lights or the receptacle or the source is having a problem give me a 12 volt test lamp and I can often find the problem and I bet I'm NOT the only one who has used a simple test lamp to trace down trailer and lights and outlet problems BUT TO EACH THEIR OWN METHODS and what works for them John T
  10. Which is EXACTLY the situation we have when we use a 50-30 adapter, Good discussion Dutch, I really appreciate and enjoy your comments HOWEVER I have to with all due respect disagree The ONLY exception I recall is for motor control circuitry NOT ANY, OTHER APPLICATIONS and the reason why was a "standard" breaker would trip upon motor starting due to the fact the initial starting surge current could be 5 to 6 times the run current THEREFORE IF AND ONLY IF it was a motor branch circuit NOT a feeder to a panelboard and if and only if the motor had proper thermal overload protection DID THE NEC ALLOW THAT EXCEPTION. What I'm so happy for is that prior to this discussion may fine lay persons did not even understand how and why using 30 amp rated cored with a 50 amp breaker WAS SUCH A HAZARD, They had no clue but now I think everyone here at least recognizes and understands how and why its dangerous and why a person shouldn't use 30 amp wire in a 50 amp protected circuit ESPECIALLY with a rubber cord laying in the water or on sharp rocks FROM the pedestal TO the RV main panel ITS JUST NOT SAFE DARN IT LOL but I agree 100% the RISK IS SMALL At lease we can allllllllllllllllll agree on that lol For sure I'm here only to help not bicker and unless a person has spent much of his lifes work and career in training and experience and working daily with the NEC I DONT EXPECT THEM TO UNDERSTAND OVER CURRENT PROTECTION but to me (even though not lay persons) it seems so obvious if you use 30 amp rated wire you need a 30 NOT a 50 amp breaker in a feeder from the pedestal to a main panelboard ESPECIALLY wire laying on the ground that can get run over or stepped oN by your barefoot grandchild............ It has been a good learning experience for many while boring grrrrrrrrrrr to others for which I apologize, but at least by now most realize the potential hazard plus the reasons why. I really really appreciate your thoughtful comments and have enjoyed our discussion, I can tell youre quite up on electrical safety. For those who still aren't and see no problem using only 30 amp wire in a 50 amp protected outdoor feeder circuit sorry I failed as a teacher but you must admit I did try yet I cant impart the whole NEC and my lifes study and experience here on a forum HECK NO TEACHER IS THAT GOOD LOL In closing I think we can all agree there is a hazard (30 amp wire in 50 amp feeder) BUT WE CAN RESPECTFULLY AGREE TO DIAGREE HOW MUCH OF A HAZARD IT IS Okay gang ???????????????????????????????? But I'm just not willing to go on record as an electrical power distribution design engineer and past NEC practitioner and say its fine no problem low risk when its so easily preventable (add a fuse or fuse wire link if not already there) while being safe (and I say NEC compliant) can prevent a fire or save a life. Those who are risk takers or are willing to get by with less then safe can do as they please............ THANKS SO MUCH to Dutch and alllllllllll others and I'm happy I'm able to help on here where others have helped me soooooooooo much. I sincerely respect and appreciate everyones opinions as I trust they in return do mine, I try my best but like all mortals make mistakes, who here is perfect and doesn't do likewise???? God Bless and keep everyone safe RESPECT ELECTRICITY it can kill you dead grrrrrrrrrrr John T BSEE, JD PS Buttttttttttttttttt while the connected load has proper rating ITS NOT THERE AND DOWNSTREAM OF THE LOAD OR RV MAIN PANEL PROTECTION WERE CONCERNED WITH,,,,,,,,,,,,, ITS THE RUBBER CORD LAYING ON THE GROUND OR IN WATER THAT GETS RAN OVER OR STEPPED ON that's a potential hazard if the wire is rated 30 amps yet its a huge 50 amp breaker !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  11. Proper maintenance can prevent troubles down the road. Loose connections can cause heat burning and arcing ..... John T
  12. EXAXCTLY thanks for pointing that out. In fact I think in certain motor branch circuits in order for the motor to start you could use up to something like 175% oversized breaker PROVIDED THAT the motor had proper thermal overload protection. So if anyone cant understand how using a breaker nearly twice as large of the conductors ampacity in the feeders from the pedestal to the RV main panel IS NOT UNSAFE AND A POTENTIAL HAZARD I tried but I just failed to educate you but that's wiith all due respect to both of us, we can just agree with the NEC's overcurrent protection o/r we can choose to ignore it and take the associated risks, why take a risk that's so preventable is my thought, why not do it RIGHT AND SAFE versus take a chance even if its small. THANKS TO EVERYONE, I appreciate and am glad I helped explain NEC and overcurrent protection which many of you were able to grasp. Your risk your choice to use proper sized overcurrent protection per the NEC or ignore it at your own peril. Be safe, God Bless all John T
  13. Ive also had good results with Hopkins wiring devices. On soooooooooo many such type trailer and device wiring problems ITS A BAD GROUND that causes it (especially if nothing seems to work) . A simple 12 volt test light can find so may problems even if the ground in the connector is bad use another iron conductive member as ground to complete the test. My troubleshooting procedure is to start at the source then the wiring from there to receptacles then receptacles to the load etc etc systematic. John T
  14. Hey heres one where many of us agree..............In our huge Naval Industrial Facility I NEVER specified or designed or told our electricians to use loc tite on electrical connections but instead use recommended torque values and undertake periodic inspection, maintenance and adjusting as required.................There were applications where proper and recommended anti oxidants were used. Consult trained professionals and the NEC if in doubt versus any opinions, lay or professional posted here MINE INCLUDED John T Retired electrical power distribution design engineer
  15. The risk is very small but its sooooooooooo easily preventable, IS IT WORTH RISKING YOUR LIFE????? Over many many years I have noticed that Electrical POWER DISTRIBUTION design engineers, professional electricians, professional POWER DISTRIBUTION Technicians (NOT talkin electronics work) that have studied, used, worked with the NEC and attended numerous seminars all understand the risks of improper overcurrent protection and all agree wire rated for ONLY 30 amps should be overcurrent protected at 30 NOT 50 amps. Sure a dead short will still trip a 50 amp breaker HOWEVER its that rare resistive short NOT ENOUGH to draw over 50 amps (breaker don't trip) but near CAN MELT THE INSULATION and a live hot wire can be exposed to water or earth or the RV or worst your barefoot grandkids AND KILL THEM DEAD. Also if its such a low risk its much cheaper to replace a 50 amp cord with a 30 amp rated BUT I BET NO ONE WOULD DO THAT and say its such a low risk YEAH RIGHT. Its the gents who don't know, understand and haven't studied the NEC and practiced power distribution for years who think they more then the NEC who ridicule or mistakenly think its not a problem THEY JUST DONT UNDERSTAND and I sure cant teach here what takes yearsssssssssssss of study and practice and works experience to comprehend and I don't expect them to BUT THAT DONT MAKE THEM A BAD PERSON they just don't understand over current protection and the hazards involved if you violate the NEC. A person who isn't a doctor or lawyer or carpenter or plumber go to them for professional advice, BUT if it comes to the NEC they know it all and MORE then the NEC and maybe just enough to get them killed !!!!!!!!!!!! Lets closed this out, I have helped and educated many of you, maybe not a few, but hey I tried my best but I'm a poor NEC teacher grrrrrrrrrrrrrr my bad WE ALL AGREE THE RISK IS LOW (but easily preventable) and if you're willing to bet your life you know more the then NEC and mistakenly see no problem with 30 amp wire in a 50 amp protected feeder from the pedestal to the RV panel SORRY I CANT HELP YOU but if I helped only one person ITS WORTH MY EFFORT AND ID DO IT AGAIN. Sure its a low risk but how would you live with yourself if a person read your opinion and conclude its okay so they ignore the NEC and their grandkid got electrocuted !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Yall can take that risk and bet your grandkids lives BUT NO WAY IM GOING ON RECORD AND SAY SURE USE 3O AMP WIRE FROM PEDESTAL TO YOUR RV It violates the very purpose and intent of overcurrent protection in the NEC which while lay persons may NOT understand professional sure do, and I after years of study and NEC practice and experience SURE DO and hey I taught a few of you at least,,,,,,,,,,,,,,,,,, I AGREE WE ALL AGREE the risk is lowwwwwwwwwwwww but it ONLY takes one mishap to kill you dead and its easily preventable so pleaseeeeeeeeeeeeeeeee pleaseeeeeeeeeeeee don't use 30 amp wire in a 50 amp protected feeder from pedestal to RV main panel Best wishes, God Bless and keep yall safe and take what risks you're willing to and just because we all dont agree dont mean I don't respect and appreciate all opinions even if they dont agree with the NEC and overcurrent protection basics. I trust yall appreciate and respect my expertise and that I tried my best to help IF IT SAVES A LIFE ITS WELL WORTH IT............... Kepe safe and happy travels John T BSEE, JD retired electrical power distribution design engineer and long time NEC student and practitioner