Re: [RE-wrenches] Fwd: Grounding on a glacier??
In an ideal world they are only hot relative to the other. In the real world there will be leakage and also faults that connect one or other pole to the grounding system. So then the other pole will thereby become hot. So, again, they are both potentially hot. And both therefore need to be fused, switched, etc... If neither pole is grounded then both must be treated as potentially hot. Only with regard to the other hot wire. If you do not reference one conductor to ground than the other one will not present any danger unless you are referenced to its mate... as in touching both wires at once. Todd ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -- Hugh Piggott Scoraig Wind Electric Scotland http://www.scoraigwind.co.uk___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier??
If neither pole is grounded then both must be treated aspotentially hot. Only with regard to the other hot wire. If you do not reference one conductor to ground than the other one will not present any danger unless you are referenced to its mate... as in touching both wires at once. Todd___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier??
Yay, Ray, That's what I like to hear! Matt T R. Walters wrote: I've worked on supposedly ungrounded high voltage systems on Electric vehicles. Got zapped when I touched the frame and a battery terminal. There definitely can be mA of leakage to ground, even if its not supposed to be there. Otherwise I welcome the move to ungrounded DC. Gee, red is positive, black for negative color coding is actually NEC compliant on an ungrounded system. R. Walters Solarray.com NABCEP # 04170442 On Jul 25, 2009, at 10:03 AM, boB Gudgel wrote: toddc...@finestplanet.com mailto:toddc...@finestplanet.com wrote: If neither pole is grounded then both must be treated as potentially hot. _Only with regard to the other hot wire._ If you do not reference one conductor to ground than the other one will not present any danger unless you are referenced to its mate... as in touching both wires at once. Todd Except of course, if there is more leakage (capacitive) from one ungrounded wire to ground than the other ungrounded wire to ground. You may still feel a tingle... The higher the voltage, given similar leakage, the higher the tingleage. (is that a real word?) I am more apprehensive about touching ungrounded and live things (although sometimes I do). People have a larger area and therefore a higher capacitance than birds do. This applies for AC (mainly) of course. boB ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.392 / Virus Database: 270.13.29/2260 - Release Date: 07/25/09 01:48:00 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier??
I have heard that this requirement (to bond negative to ground) as well as bonding one of the AC conductors to ground (neutral wire) was pushed through by wire manufactures and unions. The wire manus sell more of their product and the electricians get more labor in installing them. I also agree that grounding any live conductor actually makes the system less safe. When I have traveled over seas, I always try to open the main panel to see how things are laid out. They never associate one of their power conductors (usually 240 v) to ground. Todd Matt Tritt wrote: As long as we're already on the subject, BESIDE the NEC requiring it, why is it that we have to bond the ungrounded conductor on the battery side of a DC system??? I believe that we are the only country in the world that has this requirement. As long as all the system cabinets, mounting plates, housings and etc are grounded, what is gained by including a battery conductor? I'm not talking about HV inputs from an array, just the battery busses. I have been asking this question since forever, and the only explanation seems to be the recital of the Code. Obvious problems can occur when there is a + grounded piece of equipment in the mix, since - well, it's obvious. Matt T ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier??
Re: [RE-wrenches] Fwd: Grounding on aglacier My understanding is that it saves cost to ground one of theconductors. Then you can use single pole switches, fuses andbreakers. If both of the circuit conductors are 'hot' then youwill need to use double pole everywhere. Why? A single pole switch will stop the current regardless of whether one of the conductors is referenced to ground or not. You can test whether the neutral is grounded quite easily with amultimeter. I believe that everyone does ground it. Everywhere that I ask it turns out that it's been grounded. Herewe lately have a new wiring system called Protective Multiple Earthingwhere the ground and neutral are combined into one wire (saving oncost). This has the interesting side effect that the whole housewill become 'hot' in the event of a failure of this oneconductor. And here, if you lose the ground/neutral, you have 240v on 120 circuits. Todd___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier??
Hi Jay, An interesting quandary indeed. My thoughts are to build a grid of radials with short ground rods at the ends, extending in all directions from the equipment. This approach does not use anything but wire, short ground rods and ground connectors so there is no equipment to fail or replace. You have very low conductivity on the ice so static builds up. What you are trying to do is increase conductivity by equalizing (neutralize) the potential in the area around the communications gear. This is not really a grounding system but an effort to force all electrons to neutral in the immediate area. You want as many radials as possible in all directions from the comm gear. Make the radials as long as is practical but don't sacrifice number of radials for length, i.e. more is better. If you can leave materials behind, grow the radial network each time you have opportunity to bring in more material. For SURE you want to bond all equipment together and test these bonds with a megohm meter to make sure they are potentially the same. Then attach the equipment stack to your radial system and megohm that bond. Use as wide a copper material as you can carry in. If your problem is human contact, make sure you discharge to the radial network and bond yourself before touching any equipment. You can use a static wrist strap. A surge suppressor is useless if it has no ground reference to conduct to so I would not pursue that approach. Example of radial system for RF purposes: http://harvesting.com/tower/photos/radials.jpg That's my best guess on a solution. Let me know if you try this. Kindest Regards, Larry Crutcher Starlight Solar (928) 941-1660 Renewable Energy Products, Service and Installation Mailing Address (NO SHIPPING): 11881 S Fortuna Rd. #210 Yuma, AZ 85367 Shipping and retail store (NO MAIL): 2998 Shari Ave Yuma, AZ 85365 On Jul 22, 2009, at 7:13 AM, jason pozner wrote: Hey all, I am trying to figure out how to mitigate problems found with a 12v 500w simple DC system without a ground. This system is at 14,500' on Denali (Mt McKinly). We experienced a somewhat festive fireworks display on the 4th of July as static current from a storm seemed to travel through one of the antennae, and energized some radio equipment. There is no grounded conductor, as there is no grounding electrode, as there is no ground to put it in. The camp is situated on about 500' of glacial ice. The conductivity of the ice is questionable, and to make the puzzle a bit more fun the camp is raised and taken down at the beginning and end of every climbing season (Apr-July), though the site is the same. The loads are primarily for communications for search and rescue purposes, and reliability, and simplicity are paramount. I have been exploring the avenue of a surge arrestorsThanks, and was wondering if any of you could make a recommendation on a product that can either be reset or cheap enough to have a few replacements on hand. Everything is flown in or carried to the site, and repair/ replacement needs to be simple enough so non-technical minded personnel can perform and re-set the system. Thanks, Jay Pozner Nunatak Alternative Energy Solutions Crested Butte, CO (970) 349-3432 nunatakene...@gmail.com -- Nunatak Alternative Energy Solutions Jay Pozner and Lena Wilensky (970)349-3432 www.nunatakenergy.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier??
Larry Crutcher, Starlight Solar wrote: Hi Jay, An interesting quandary indeed. This is another good example of an application that I was trying to grill Sunpower about --- as far as grounding their modules that need to be positive grounded in order to take advantage of their higher efficiencies. They couldn't answer this simple question. How would you use one in an airplanefor instance ? There are solar powered airplanes (sort of) Is a large faraday shield enough ? Sort of like the ground radials that Larry has mentioned. I would imagine that if you get large enough radials that it ~might~ approach being a virtual ground. Works for antennas though. I like questions like this one. Sure makes one think a bit. boB ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier??
As long as we're already on the subject, BESIDE the NEC requiring it, why is it that we have to bond the ungrounded conductor on the battery side of a DC system??? I believe that we are the only country in the world that has this requirement. As long as all the system cabinets, mounting plates, housings and etc are grounded, what is gained by including a battery conductor? I'm not talking about HV inputs from an array, just the battery busses. I have been asking this question since forever, and the only explanation seems to be the recital of the Code. Obvious problems can occur when there is a + grounded piece of equipment in the mix, since - well, it's obvious. Matt T boB Gudgel wrote: Larry Crutcher, Starlight Solar wrote: Hi Jay, An interesting quandary indeed. This is another good example of an application that I was trying to grill Sunpower about --- as far as grounding their modules that need to be positive grounded in order to take advantage of their higher efficiencies. They couldn't answer this simple question. How would you use one in an airplanefor instance ? There are solar powered airplanes (sort of) Is a large faraday shield enough ? Sort of like the ground radials that Larry has mentioned. I would imagine that if you get large enough radials that it ~might~ approach being a virtual ground. Works for antennas though. I like questions like this one. Sure makes one think a bit. boB ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.392 / Virus Database: 270.13.25/2256 - Release Date: 07/23/09 06:02:00 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier, SunPower modules
I have installed tons of SunPower 90's without any ground connection on RV's with noticeable loss of power. I believe the problem only occurs when you have a path to ground from the frame. Larry On Jul 23, 2009, at 12:58 PM, boB Gudgel wrote: Larry Crutcher, Starlight Solar wrote: Hi Jay, An interesting quandary indeed. This is another good example of an application that I was trying to grill Sunpower about --- as far as grounding their modules that need to be positive grounded in order to take advantage of their higher efficiencies. They couldn't answer this simple question. How would you use one in an airplanefor instance ? There are solar powered airplanes (sort of) Is a large faraday shield enough ? Sort of like the ground radials that Larry has mentioned. I would imagine that if you get large enough radials that it ~might~ approach being a virtual ground. Works for antennas though. I like questions like this one. Sure makes one think a bit. boB ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier, SunPower modules
Larry Crutcher, Starlight Solar wrote: I meant to type ...NO noticeable loss of power. Hi Larry But how do you ~really~ know you weren't losing power because of their lower efficiency unless there was a comparison made ? :) I'm not sure that I believe it's all that much of a problem, either. But seriously, I think that what Sunpower ~really~ means is that they have a problem with their lower efficiency on high voltage strings. I don't imagine that an RV installation would be that high of voltage ? I would just like Sunpower to explain this all a bit better. boB On Jul 23, 2009, at 7:27 PM, Larry Crutcher, Starlight Solar wrote: I have installed tons of SunPower 90's without any ground connection on RV's with noticeable loss of power. I believe the problem only occurs when you have a path to ground from the frame. Larry On Jul 23, 2009, at 12:58 PM, boB Gudgel wrote: Larry Crutcher, Starlight Solar wrote: Hi Jay, An interesting quandary indeed. This is another good example of an application that I was trying to grill Sunpower about --- as far as grounding their modules that need to be positive grounded in order to take advantage of their higher efficiencies. They couldn't answer this simple question. How would you use one in an airplanefor instance ? There are solar powered airplanes (sort of) Is a large faraday shield enough ? Sort of like the ground radials that Larry has mentioned. I would imagine that if you get large enough radials that it ~might~ approach being a virtual ground. Works for antennas though. I like questions like this one. Sure makes one think a bit. boB ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fwd: Grounding on a glacier, SunPower modules
boB, I usually put only two in series and use MPPT to down convert to 12 volts. Some RV customers have 6~8 modules, series/parallel. I promote the use of battery monitors in all systems so if there was a performance issue, I would have seen or heard of it by now. RV customers have nothing better to do than to stare at the monitors. Really though, most RV full-timers are a dedicated group of off- gridders conserving energy and water resources. Now that you and Dan mention it, I did hear that the polarization effect did not occur at low string voltages. I have never installed any high voltage strings with SP. Larry On Jul 23, 2009, at 7:56 PM, boB Gudgel wrote: Larry Crutcher, Starlight Solar wrote: I meant to type ...NO noticeable loss of power. Hi Larry But how do you ~really~ know you weren't losing power because of their lower efficiency unless there was a comparison made ? :) I'm not sure that I believe it's all that much of a problem, either. But seriously, I think that what Sunpower ~really~ means is that they have a problem with their lower efficiency on high voltage strings. I don't imagine that an RV installation would be that high of voltage ? I would just like Sunpower to explain this all a bit better. boB On Jul 23, 2009, at 7:27 PM, Larry Crutcher, Starlight Solar wrote: I have installed tons of SunPower 90's without any ground connection on RV's with noticeable loss of power. I believe the problem only occurs when you have a path to ground from the frame. Larry On Jul 23, 2009, at 12:58 PM, boB Gudgel wrote: Larry Crutcher, Starlight Solar wrote: Hi Jay, An interesting quandary indeed. This is another good example of an application that I was trying to grill Sunpower about --- as far as grounding their modules that need to be positive grounded in order to take advantage of their higher efficiencies. They couldn't answer this simple question. How would you use one in an airplanefor instance ? There are solar powered airplanes (sort of) Is a large faraday shield enough ? Sort of like the ground radials that Larry has mentioned. I would imagine that if you get large enough radials that it ~might~ approach being a virtual ground. Works for antennas though. I like questions like this one. Sure makes one think a bit. boB ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re- wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
