Author	[Modern View]
Little Ed 06-24-2012 11:18:36 71.86.26.2 Report to Moderator	The more I read of the grounding questions, the more confused I become. I have three wires coming from the meter box to a distribution box below the meter, three wires going to the house, three wires going to the barn.(line1, line2, and insulated neutral)with neutral bonded to ground at the distribution box only. I can plug the camper into a 110 receptacle in the barn, and I will get get 35 volts AC measured from the camper door to the earth that I am standing on. I can find no continuity from any conductors to the frame of the camper. I can then plug the same extension cord into a 110 receptacle at the distribution box, and come up with zero voltsbetween the camper dooor and the earth I am standing on. So, am I wrong in thinking that I need to add a ground rod at the electrical panel at the barn, and bond it to the neutral? I know that it has been said that there should be only one ground rod in an electrical system, but how does any stray voltage that enters the bare groundwire (green screw at the receptacle) make it back to earth ground unless it is bonded back to neutral at each electrical box? Should the electrical box itself be gounded to earth? Another thought that runs through my head is that adding a ground rod to dissapate stray voltage would create a dedicated path, and thereby a short circuit. I must be missing a few synapses to not be able to get my head around this. (perhaps my brain cells are not properly grounded) Thanks for reading this Ed [Reply]   [No Email]
HollyFarmer 07-01-2012 17:46:08 199.68.112.2 Report to Moderator	Re: Flogging a dead horse....Elect. ground in reply to Ted in NE-OH, 06-24-2012 11:18:36   jackinok, much better explained than what I could have. Oh and I totally agree. [Reply]  [No Email]
HollyFarmer 07-01-2012 17:42:04 199.68.112.2 Report to Moderator	Re: Flogging a dead horse....Elect. ground in reply to Stan in Oly, WA, 06-24-2012 11:18:36   Quoting Removed, click Modern View to see Just my opinion...but never put more than one ground rod in a system. By doing so you could actually set up a ground field potential, which under the right circumstances, could be fatal!!. By having only one ground rod, you are limiting the Line to earth potential. By that I mean that the farther you are from the ground rod, the less chance there is of getting shocked. [Reply]  [No Email]
jackinok 06-25-2012 07:21:50 162.58.82.136 Report to Moderator	Re: Flogging a dead horse....Elect. ground in reply to Little Ed, 06-24-2012 11:18:36   maybe i didnt explain that very well,what you experience on a camper,barn etc when you measure voltage to ground is a GROUND LOOP.basicaly its caused simply because the earth itself has a resistance.when you put your meter (or yourself) between earth and ground with a device such as a genset bonded to trailer/camper you make a path of less resistance to ground in which current flows just like water.the farther you are from the actual physical ground rod at the source,the greater this can become.( thus the idea of having one ground rod).in reality you should lift the bonding straps off your genset and inverters when you use a camper on ac,and replace them when using the genset,inverter etc.years ago many campers,equiped with a genset had a actual physical power cord you had to plug into where the commercial power came into trailer.this when you had a ground rod at your trailer became a totally depicated stand alone system. with no possibility of a ground loop back to commercial power. the reason,why barns and things do this is simple.many times folks when they build a barn or out building they add breaker boxes in side,not a bad idea,but when they wire it up they use a box with a connection point for a main breaker box and bond the neutrals to the grounds there.since this box is generaly touching metal somewhere this creates a ground loop.just like on a genset.when adding this box if they would simply twist the neutral and grounds without using the screws this wouldnt happen.or if they would use a box with a dedicated and isolated neutral bar. The reason the electric company uses so many grounds on each transformer pole is that each transformer is a stand alone dedicated system.ground wires on line poles are often added to keep the neutral at or near ground potential,and to decrease the natural occuring static that builds up in above ground lines.OR to preclude the possibilty that if a neutral line does go down,that feedback thru a transformer doesnt heat up a neutral to line voltage which can be often 20,000 volts.this is why you should never touch a electric companies lines if they are down.even the neutral has the potential to be at line voltage,but not spark,but if you pick it up off ground it will become live and YOU are its path to ground.same basic thing as what you experience in your trailer,ground potential. [Reply]  [No Email]
jackinok 06-25-2012 06:19:36 162.58.82.136 Report to Moderator	Re: Flogging a dead horse....Elect. ground in reply to Little Ed, 06-24-2012 11:18:36   try pouring some water around the ground rod at your box and retest.you can lose your ground on a ground rod and the whole system the floats above ground.doesnt seem to be your problem but its possible. electrical code calls for one ground rod. BUT, many campers are equiped with generators,and most of these have a ground strap to the frame somewhere, or to the skin of the camper.nearly all have a inverter to run on dc also that might be bonded.this creates a sort of a ground loop type problem in that you have basicaly three systems wired for stand alone use on one camper. what you are reading is ground potential.in other words, basicaly the difference in ground carrying potentail/resistance of the ground itself.campers are kind of tough because they in theory should be grounded only at the pole when on ac,only at the genset when running on it,and only on the inverter when its running on it.since each would be a stand alone system at that particular time.I personaly believe grounding the trailer/camper wouldnt be a bad idea,each time you park,otherwise you probably should disconnect the grounds on your genset and inverter when plugged into ac. but again its not code unless any one of the three are running as a stand alone system. [Reply]  [No Email]
buickanddeere 06-24-2012 13:43:48 216.183.136.150 Report to Moderator	Re: Flogging a dead horse....Elect. ground in reply to Little Ed, 06-24-2012 11:18:36   Tough to long distance diagnose but it looks like elevated ground potential due to either VD on the neutral and poor system grounds everywhere. Or an open service neutral and current returning via the grounding system. Not "one ground rod in the electrical system" BUT "one ground bond to the neutral in the electrical system". Problem is not every service has the proper L1,L2, insulated neutral and bare or insulated ground. Over head triplex is a nasty hangover from the old days before they knew better. If you have live stock they maybe getting shocked at water troughs, metal stalls etc. Does the camper have the neutral and ground bonded for use with a floating neutral generator.Or an un-bonded neutral for use with a bonded neutral generator? [Reply]  [No Email]
DH in Carolina 06-24-2012 12:19:00 173.212.10.166 Report to Moderator	Re: Flogging a dead horse....Elect. ground in reply to Little Ed, 06-24-2012 11:18:36   Check the receptable at the barn to see if the ground wire is connected to it. Drive two ground rods at least 6 feet apart and bond to the panel box at the barn. All the equipment grounding conductors should be bonded to the barn panel also. Do not bond the neutral at the barn panel. Ideal situation would be four wires from main panel- L1, L2, Insulated neutral , and equipment grounding conductor. [Reply]  [No Email]
old 06-24-2012 11:25:57 209.86.226.34 Report to Moderator	Re: Flogging a dead horse....Elect. ground in reply to Little Ed, 06-24-2012 11:18:36   Tha can be caused by a few things. Something as simple as the camper having the neutral and hot wire switched around or that being so in the plug. But yes it is a good idea to always have a ground rod at each and every building you have power to. Shoot even the electric company has a ground wire on each and every electric pole [Reply]  [No Email]
Little Ed 07-04-2012 09:31:51 71.86.26.2 Report to Moderator	Re: Flogging a dead horse....Elect. ground in reply to old, 06-24-2012 11:25:57   Thanks to all who replied, giving me a lot to work on. I have found that there is a problem with the camper, got an unexplained draw in the heater 12v circuit. Gonna wait for temps to get cooler before I spend much time in there. [Reply]  [No Email]