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Hello folks; I’ve been a builder since 1977 and have had to do everything that’s required to build my type of projects at some time or other, from digging the footer on. The electrical portion of the job has never been all that appealing to me, as I prefer woodwork, and it is my weak area when it gets past basics.
I’ve been working on an addition to my own place whenever I can and have a questions for the electrically enlightened. I put a 100 amp sub-panel in the new part, and fed it with three #2 wires from my original 200 amp box. This of course is two to the 100 amp breaker in the sub-panel and the other to the neutral bar. I ran a bare copper to a new ground rod, and wired the addition. Neutral and ground wire from the new circuits are mixed on the single neutral bar; in other words, I didn’t isolate the neutral from the ground. I’m somewhat aware of the practice of replacing the little metal jumper in the box with a plastic one and running a ground back to the supply panel, but have never fully understood why what I’ve done would not be safe. I added another 100 amp panel the same way for a workshop some years ago, and am wondering if I should change something. I also know that some of the electric code is… trivial, and some things are not necessary from a practical standpoint. Although my work will not be inspected, I do want it safe. Can any of you shed some light on this for me? Real plain and simple, is my wiring safe as I have it? Would it be really worthwhile to make the changes? What would you do in this situation? Thanks in advance for the info.
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Travis buddy....Why are you doing it wrong boy????
You know whats right....Do it right then. The idea is the ground is to stay unenergised except for safety back up. You are blowing it with your methods. You are not saving time or money. So you are just being stupid.
Hows that for an answer....near the rediculous wanna be bad electrician stream,
aj
Nothing personal mind you.
*OK, as simply as possible, what the NEC says about connecting the neutral and ground is that it is required at the service entrance, and forbidden everywhere else. The common mistake is to connect them at sub panels. If you drive an additional ground rod at a sub panel, as is required for a separate building, connect it to the ground only. The ground rod is in addition to, not instead of, connecting the sub panel ground to the rest of the system.Neutral carries the current used by your lights and appliances, etc. Ground is not supposed to carry any current at all, except when things go wrong and a hot wire comes in contact with something grounded, like a box or conduit. In that case, the ground is there to carry enough current to trip the breaker or blow the fuse, returning the system to a safe (but non-working) condition.If the ground is allowed to carry normal working current in addition to the neutral, and at some time the neutral comes loose, then the ground system is carrying all the working current. Ground usually is through things like conduit, and just let one joint come apart, and you have the lights go out and part of the conduit go hot. If everything is tight and solid, it's only a little bit dangerous. But with electrical things, stuff a little bit wrong here and there tends to accumulate until you have something really dangerous and hard to figure out.-- J.S.
*AJ: Guess I just had to hear what I already knew. Some of you contractors know how it is...using a salvaged box, bits of leftover this and that, doing things at home that you'd never do on the job. I guess I'm dense, but I still don't see how it can be dangerous, unless it was coupled with somthing wired with the polarity wrong... Thanks AJ.Travis
*Thanks John; it's beginning to soak in. Good explanation. Would you change it on your own house?Travis
*Yes, absolutely, I'd fix it on my own house. It's just a little screwdriver work to put it right. Do it some morning when you have daylight to see by.-- J.S.
*One hand in the panel....one in the pocket.Dry feet in dry rubber boots on dry wood.Don't hold the shaft of the damn screwdriver.If you're like me....I pull meters to do extensive reowork in live panels...Screw the utility tag...pull it apart and put it back together...In a subpanel....just shut off the feed circuit breaker.near idiots ready to jolt there way to hell,aj (Mr. Easygoing)
*Thanks aj, You just broadened my horizons. Never cared to touch that boxcar door tag unless the electric company and a permit was involved. Spent way too much time at full concentration level in hot panels. Never screwed up -- guess cause I couldn't. thanks for putting it in perspective.Couple of clarifications on the remote box. Neutral bus not bonded to the box. And a seperate ground busbar bonded to the box. If the cable is routed underground through thin metal conduit this ground connection will rust out in 10 years or so and that ground rod will have to do any future grounding on it's own(tighten that clamp). Plastic conduit or underground cable with a seperate ground wire from the main panel makes sense if we really want to cover the bases.Good Building,Jim Malone
*Jim, That little tag on the box used to bother me too; wondered about the power company et al.... Called 'em up one day when I just couldn't get around pulling the meter... "Need to know about pulling the meter, permit, etc"... "Just pull it!" Told me to let 'em know when I was finished and they'd come out and put a new tag on it. Never did get around to calling 'em. Mr. "Easygoing", you working on some rap lyrics? "Wanna' be bad...." You've got a future, I can hear it now. Sam
*>. If the cable is routed underground through thin metal conduit this >ground connection will rust out in 10 years or so and that ground >rod will have to do any future grounding on it's own(tighten that >clamp).In that case, the impedance to ground will be way too high to ever trip a breaker, so any hot wire that comes in contact with a box or conduit will merely make all the boxes and conduit in the outbuilding hot. That's why your following idea is by far the best:> Plastic conduit or underground cable with a seperate ground wire >from the main panel makes sense if we really want to cover the >bases. -- J.S.
*John, Wouldn't I have to run a ground wire back to the main panel? As of now I only have three #2 cables (two hots and a neutral)running from the main to the sub. So as I understand it, I isolate the neutral and grounds (which means I'll have to drill, tap and add a new bar) abandon the ground rod I drove for the sub panel and route a ground back to the main box; remove the bonding strap from the sub panel and replace the little metal jumper with a plastic one. Sound right so far? Thanks for your help John. I seem to be getting a little sarcasm from one of our buddies...maybe it's just the cold weather...Travis
*My non-professional thought is that you should run the ground wire and divide the neutral and ground wires at the sub-panel but that you could and should leave the ground rod connected at the sub-panel. There may be some situations where the ground is not required to be run back to the main panel, but I think that it is recommended that you do so. There is a long thread on a very similar situation over at Dan's Housewiring Forum You may want to specifically check the response regarding a shop 80' distant from a house at:http://pub38.bravenet.com/forum/fetch.php?id=9443003&usernum=3262220071
*subpaneling wiring related question.I installed a GE electric hotwater heater 6 months ago, wiring it to a 100 amp subpanel. The unit does not have a neutral wire, only the 2 hot wires and a ground wire. Could someone please tell me how the ground should be wired in the panel, to the neutral bus or to the ground bus? Wouldn't wiring it to the ground bus negate the separation of neutral/ground rule? Also, does this heater adhere to code? Is it possible to rewire the heater to make it correct?Thanks for any help, Jim
*Thanks Casey. I went to the web site you listed; been there before but had forgotton it. Got it bookmarked now.Travis
*Jim, Assuming you have a 220 volt heater , you should have the two hot wires and a grounding wire. The grounding wire should be hooked to the grounding bus in your subpanel along with all the other bare grounding wires. Your neutral bus in the subpanel should be isolated from the box and your grounding bus should be screwed to the box to make contact. These are two different busses and they should not be connected to one another.
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Hello folks; I've been a builder since 1977 and have had to do everything that's required to build my type of projects at some time or other, from digging the footer on. The electrical portion of the job has never been all that appealing to me, as I prefer woodwork, and it is my weak area when it gets past basics.
I've been working on an addition to my own place whenever I can and have a questions for the electrically enlightened. I put a 100 amp sub-panel in the new part, and fed it with three #2 wires from my original 200 amp box. This of course is two to the 100 amp breaker in the sub-panel and the other to the neutral bar. I ran a bare copper to a new ground rod, and wired the addition. Neutral and ground wire from the new circuits are mixed on the single neutral bar; in other words, I didn't isolate the neutral from the ground. I'm somewhat aware of the practice of replacing the little metal jumper in the box with a plastic one and running a ground back to the supply panel, but have never fully understood why what I've done would not be safe. I added another 100 amp panel the same way for a workshop some years ago, and am wondering if I should change something. I also know that some of the electric code is... trivial, and some things are not necessary from a practical standpoint. Although my work will not be inspected, I do want it safe. Can any of you shed some light on this for me? Real plain and simple, is my wiring safe as I have it? Would it be really worthwhile to make the changes? What would you do in this situation? Thanks in advance for the info.