Need Help Sizing Wire to Run from Outdoor Submain to a Building
Norn Bartel
7 years ago
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Type of wire to run as a ground
Comments (16)"The NEUTRAL bar is only legal in certain specific instances. Otherwise, even though it is ultimately grounded, it is not legal to provide equipment grounding connections." To use your own words, you are "wrong". Unless there is a separate ground bar in the panel that is properly connected to the neutral bar with a proper sized bonding jumper, it is the ONLY place in the panel to land a egc. THE ONLY PLACE. Do you get it now? The entire reason to bond the neutral to the ground rod and water line (within 10' from wher it enters the building) is to provide a path for fault current back to the neutral (xo in a transformer, or the "bullseye" as some refer to it) So you are saying that in the situation of the OP, equipment grounding conductors ARE NOT to be ran to the neutral bar in the panel? That's quite amusing to me. If one was to run a new 12-2 nm cable for a new circuit would you then just NOT land the egc of that nm cable in the panel on the neutral bar which is bonded to the ground rod and water line? What then would you do with it? Think about it. Of course you would land it on the neutral bar in the panel. That is where it goes, of course if there was a ground bar secured to the panel tub and bonded to the neutral bar then all grounds should be on the ground bar and all neutrals on the neutral bar and there shall be only one point of connection between them in the panel, by a properly sized bonding jumper. But thanks for once again trying to make be look bad for some reason, just to make yourself feel smarter I guess. "Your subsequent response was incorrect and unsafe." Sorry, you're wrong again. My ingormation is just different than yours, and in compliance with the NEC. Man you are quite the "high and mighty" type aren't you? I'm done with this thread because I actually have more important things to tend to than trying to calm an electrical egomaniac. Go ahead and cut others down to your hearts content but I'll not give you the satisfaction of wasting any more of my time. Good luck to the OP....See MoreCost of Wire for 200 Foot Outdoor Run From Pool Heat Pump
Comments (43)OK, back to the subject at hand. I'm assuming that you all agree with sticking to the #6 copper for this long of a run? Yes? No, I think the consensus was that #8 copper would suffice. The reason that's somewhat tentative has to do with the power demands of HVAC motors (i.e., a heat pump--and trust me, we do understand how a heat pump works). Had this been a simple requirement for a 50-amp general purpose circuit, then I think #6 wire would have been the straight-up choice. However, HVAC equipment behaves a bit differently than a general purpose circuit in that it has both a minimum and maximum circuit ampacity rating and special code sections apply. Cutting to the chase (and at the risk of oversimplifying), the minimum circuit ampacity is what the equipment needs to run after it has overcome the starting surge of its major component--the compressor motor. The maximum circuit is to allow for the starting surge, which can be several times the running load, lasts only briefly and does not pose a significant threat of overheating the conductors. Thus, a heat pump is a specific situation where it is appropriate to use a larger OCPD (circuit breaker) than might ordinarily be used with a specific wire guage. But this isn't done by "guess and by golly"; it's based on the known faceplate ratings of the dedicated equipment. In the thread discussion above, you'll note that there was some variance of opinion. Because I couldn't locate info on the minimum circuit rating, I initially took the conservative tack of recommending #6. (Forgive me if I'm wrong, but I think jmvd20 took a similarly "safe" route too.) At the very least, the OP would have a safe result that would be uncontroversial in the view of any inspector. Ron, on the other hand, being more familiar with the particular type of equipment, was certain enough that the MCA was low enough to be fed by #8CU under these environmental circumstances. After some discussion about that, I'm inclined to agree with him although, as someone who doesn't deal with this equipment frequently, I'd tend verify the manufacturer's specs (which were not available online) before opting in that direction. But I'd add that Ron's interpretation also satisfied my "common sense" test based on a rough guestimate of the approximate wattage consumed by a 5hp motor. Thus, it isn't at all certain that #6CU is required. I believe the consensus is that #8AWG/CU is adequate. "To allow for both voltage drop and terminal size problems that the larger diameter #2 aluminum would cause, per my bad experience!? With the entier distance in conduit as you all are "by the bookers", Right? In making our recommendations, both Ron and I (and perhaps others) considered voltage drop at the 200' distance. Using 35 amps as the estimated running load, here are my calculations: A 200' run of #8CU in conduit, delivering 35A at 240V yields a voltage drop of 4.9%, which is under the usual target of 5% (i.e., it's borderline, as I said, but acceptable). At 50A, the drop is about 6.5%--a drop that most motors can tolerate quite readily. Under the same assumptions, if we use aluminum wire instead of copper, it will need to be upsized to #6 in order to meet ampacity requirements. Again at 200', the voltage drop calculations for #6 aluminum are very close to those for #8 copper (4.7% @ 35A and 6.8% @ 50A). Any way you look at it, #2AL is way, way overkill for the OP's application. And that's why I called you on the statement that you used a chart that equated #2AL with #6CU due to the distance. That doesn't make sense to me and I'd love to see that chart. Now, if it was the only underground-rated AL wire that happened to be available from your supplier, then fine, just say so. Now here's what strikes me as particularly ironic: While you take issue with "going by the book" because, you contend, the book is mostly overkill, it was going by the book--strictly--that led the cost-saving recommendation to use a smaller and less expensive wire guage! OK, sorry, enough of that. 1. As I have stated in both previous thread entries. "I would NOT have attempted the project if I thought it was dangerous to anyone's safety"! So you all are saying that you "always" complete your "own" projects per the "letter" of the law and not the "spirit" of it. Meaning, on your own land when you know that if you where to deviate from the law/code, the chances of the "risk" taken is a billion to one shot of going wrong that you would still ALWAYS go by the letter of the law? In my opinion, The code is an "overkill" guide so that people that have very little common sense will not get themselves or others injured or killed. Agreed? No, not agreed. In fact, the less you know, the less capable you are of assessing the risks and, therefore, there's all the more reason to adhere to code strictly. Personally, I'll admit to doing some pretty half-a$$ed things in the past but, honestly, the older I get (I'm 62 now), and the more I learn, the more I do, in fact, "complete [my] 'own' projects per the 'letter' of the law." As for the code being "an 'overkill' guide so that people that have very little common sense will not get themselves or others injured or killed", I agree only to the extent that there are certain safety margins built in, much like there is a over-design requirement when engineering a bridge. And I'd also agree that a few of the requirements seem like unnecessary nuisance and expense--child proofing all the receptacles in an adult-only home comes to mind. But even there, standard requirements contemplate not only your personal requirements and tolerance for risk, but those who may occupy the premises at a later time. As the code evolves, with new editions coming out every three years, a great many of the new requirements are based on actual documented experience. That is, there is statistical evidence of a problem that caused actual fires, actual injuries and actual deaths. Since there are only about 300 million people in the U.S., these problems are not in the order of one in a billion or they would not have statistical support. 3. The thick plastic around the wire & plastic conduit for that matter becomes very brittle and is degraded very quickly from the sun / UV rays, due to the 100 plus degree temps in summer and 320 days of sun a year. SO the best place for the wire IS underground. And metal conduit would just melt any plastic sheathing on wire from the suns heat. No one here disputes that the OP's proposal to run the conduit underground is a good idea and I certainly didn't hear anyone suggest metal conduit. Interestingly, if you familiarize yourself with the code, you'll discover that all these factors are well-accounted for. Ambient temperature, for example, is a definite factor in selecting cables and wires. So, too, is sun exposure. Where conditions fall outside normal expected ranges, there are wire types and methods specifically designed for such conditions. BTW, if you post for advice here, make sure to mention that your project is in the desert where the temperatures and light exposure are very high and you'll get competent advice for those conditions. In sum, there is no real reason to "choose the 'illegal' way." Jes my 2c and a "good day" to you too, sir....See MoreRunning wires without attic or basement
Comments (14)An 18 inch auger drill bit allows you to drill in the middle of a stud despite an angled entry from the rest of the drywall. A 3 inch strip of drywall is enough to run receptacles around a room. For vertical work you can cut about 6 inches below the wall ceiling joint, drill through the top plat, and then fish from the opening ion the ceiling. Worst can you open the ceiling 5 inches from the wall and work from there. Inside corners take more time to repair than flat work, so avoid damaging them....See MoreJacuzzi wiring; outdoor EMT, THHN vs Romex, distance above grade
Comments (19)"On the building" is precisely where Joey's electricians are proposing putting the conduit. That is the only thing pertinent to this conversation. The circuit is not going to a hot tub in the middle of the yard, but a bathtub on the second floor. In my experience, the reason EMT is not allowed between the disconnect ON the house and a hot tub in the middle of the yard is that it is only allowed on or above grade....so the electrician puts it on top of the ground, and someone trips on it and bends it. Then the homeowner buries it in 2" of dirt, etc, violating codes. Any other conduit is either stronger, or able to be buried, so EMT is just the wrong/worst choice if it can't be attached to and supported by the building. MC would have to be a type rated for wet locations where applicable. Probably not the same stuff you are thinking of....See MoreNorn Bartel
7 years agoNorn Bartel
7 years agoyankee4210
7 years agoRon Natalie
7 years agolast modified: 7 years agoNorn Bartel
7 years ago
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