was out at the barn tonight looking at my 100 amp sub panel.i wired it so i can’t blame anybody else.
so i have 4 wire coming to it,where the common comes in i have removed the bonding screw.
the bar joining the 2 ground strips have been removed, all the commons are on one bar and all the grounds on the other one.
now heres my question, i see that i run a ground from the ground bar to the box,basiclly grounding the box. is this correct? i just can’t pull it from my head. larry
if a man speaks in the forest,and there’s not a woman to hear him,is he still wrong?
Replies
The terminal block for the equipment grounding conductors (i.e. "ground wires") is normally grounded to the box - in most (all?) boxes I have seen it is automatically grounded by one of the attachment screws. The "neutral" conductor terminal block is isolated from the box.
Yes, you done good.
Assuming the barn is totally removed from the main bldg.
I thought the sub panel was supposed to be bonded w/an additional ground rod?
Set me straight.
Ray
"I thought the sub panel was supposed to be bonded w/an additional ground rod?"No.It needs grounding RODS, if rods are the type of grounding electrode used. You either need to use 2, a min of 6 ft apart (IIRC the number) or need to measure the resistance to less than 25 ohms and that is a specialized test that is very rarely done.The problem is that there are several "grounds" and in general it is clear what the difference is, but not when you are at a panel.In this case you have an equipment grounding conductor from the main panel, equipment grounding conductors that go the individual circuitrs, you have the ground electrode conductor(s) that go to the ground electrode(s), you have the ground buss, you have the metal panel case, and you might have wires to bond other items such as water pipes (if they are not part of the ground electrode system). And all of these are on time or another are called "grounds". And they are all bonded together at the panel.So it is not clear if he did not understand that he also needed a ground electrode system or if he already knew that and was handling it and was only asking about bonding or not.What he asked about was bonding the "ground bus" to the panel, as I understood it.Now it was not clear how the panel was constructed. Some use to floating busses with two straps that go to common screw that bonds them to the panel. In that case all you need to do is to remove one strap. Others have one buss that is bonded and a strap to a floating bus. In that case just remove that strap.Others have one bus that is floating, but has a bonding screw. Remove the bonding screw and you have a neutral bus. You need to add a separate ground bus kit where the bus bolts directly to the panel.Apparently there are some other options. As he apparently has 2 floating busses (if he correction reported what he has). And he needs to bond the one to the panel. That is the way that I read it.And is doing that with a wire from the bus to the panel case. But I am not sure, but I am not clear on what he has or is doing..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I understand the 2 rod or ufer ground requirement (didn't know it exactly-you refreshed my memory)
BUT - Don't you still treat the out building like a new service ie. bonded neutral?
OR- since a 4th wire (ground) was run. Is this considered a 'metalic path' and the panel is treated like a normal subpanel?
The rule is that if there was not another metical path, other the electrical power, then you had the option of going with a 3 wire system and treating it like a service entrance and bonding the neutral to to the "grounds".I have not seen it, but I understand that the 2008 NEC no longer allows this option.If a 4 wire system is used then the sub-panel is identical except that the neutral supply line and neutral bus are isolated from the "grounds".The need for a ground electrode system and bonding is the same in either case..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I just went to a seminar on the changes to article 250 in the 2008 NEC the other day. You're right, a separate neutral and ground wire will be required for this situation under the new version. There's a bunch of other new stuff that will be introduced...it gets more and more complicated with every update, it seems.
They touched on ground fault protection requirements during the seminar as well. Sooner or later, they're going to require either GFCI's or AFCI's everywhere - the 2008 NEC calls for GFCI protection on dedicated receptacles in basements for things like freezers and sump pumps, as well as the receptacles in garage ceilings used for garage door openers.
bill, i have a semmens 100 amp panel that i'm using for the subpanel. when you open the box there is a bonding screw at the point that your netural scews down. i have removed that screw. now there is a bar that connects both bars, i removed that so that both bars are independent of each other.both are floating at this point. all my neturals go to the side where the main incoming netural is. then all my grounds go to the other bar which also has a ground coming from the main box.
i think from what everyone has said here i have grounded my metal box correctly with a wire from the ground bus to a screw into the box.
i also have a ground rod drove and am connected to it at the ground bar. thanks larryif a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
I am not familar with that panel.And what you ended up with it fine..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Place I'm working at now has a "Challenger" brand panel.
Are those breakers interchangeable with any other brand? See siemens, square D or cutler hammer all over but never "challenger."
(sorrY OP --to jump in on you for Bill?)
while were waiting for bill,i hit you with what i know, ge,semmens,i believe square d will all fit the challenger,but one brand is not ul approved for the other brand even though they fit.
so you may pick up some liabilty by using different brands. larryif a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
THanks--yeah, I see this box has more than one type of breaker in it.
Bryant begate Westinghouse, which Begate Challenger, which begate Cutler-Hammer BR series.Now I saw some references to some other style Challengers breakers which looked more like the ITE style.But if it look like the modern panels then the BR series is the direct replacement.http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&Rendition=Primary&&dDocName=1016115403174.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thank you Bill.
Pat
Actually, Westinghouse begate Bryant which was the brand used by their wiring device division and the residental / light commercial electrical line (wiring device div. later sold to Hubbell) .Challenger (former Zinsco/Sylvania line) was bought by Westinghouse, then Eaton bought Westinghouse's line and merged it into Cutler- Hammer* .( The BR line is a favorite of bottom feeder/hack electricians)
Eaton has owned C-H since around 1979 and since they used West. for larger frame breakers, was a good fit.
Ok that makes sense. I did a google as I did not remember be sure if the Challanger was one that ended as CH/BR or not.And I saw some the 3rd party breaker reseller and saw some that looked like Zinsco breakers..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Hey Ray,
The OPs question was, to paraphrase, 'did I do the right thing in bonding the panel housing to the equipment ground bar?'
The simple answer is, yes.
The other advice--you need ground rods if a separate structure, is correct. Giving a primer on grounding a separate structure is all well and good, and may help the OP, but it's not a response to the simple question he asked.
Based on the other info the OP gave--he ran a 4-wire feed--it seemed to me that he is well-informed, and so I figured the chance is pretty good that he also installed a grounding electrode at the separate structure. But maybe not.
Cliff
The subbox get's grounded and then back to the ground in the main box. It's the neutral busbar that you don't want bonded in to the subbox--but all the way back to the main box, if memory serves me.
Basically you want to separate the neutrals and grounds in subpanels, so you don't end up with current in the ground before the main box, right?
I think you have done good, but there is an outside chance you may have it backwards.
Just to clarify: There are two bars in the box, you have all commons (white) on one bar and all grounds (bare or green) on the other. You removed the bonding jumper between the two bars. This is all good.
The question: Is the bar where your grounds are connected electrically connected to the box enclosure? It should be. Could be connected via its mounting screw(s) or by a small bar inserted into one of the holes with the other end attached to the box enclosure with a seperate screw.
Bottom line:
There should be continuity between the metal box enclosure and the bar where you have all of the grounds connected.
There should not be continuity between the metal box enclosure and the bar where you have all of the commons connected.
Jim
I believe you should also have a ground rod. At least the last time I did a sub-panel in an accessory building we had to have the ground bonded back to the main panel ground AND have a secondary ground rod in the ground at the panel.
As long as you have the ground bar connected to the ground back to the main panel and the neutral likewise, that part sounds correct.
See my reply to boats.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Larry, I showed a house this week that is part of an estate sale. It's a $215,000 house
In the garage is a car for sale. A 2000 Lincoln Town Car - one owner with 55,000 miles on it.
They want $7,000 for it. Its champagne color with leather seats and appears to be in excellent condition.
It sold new for $43,000. It's 25 MPG on highway and 18 in town.
It's a nice looking car. Just wondered if you would be interested. If so, let me know and I'll get you the info.
i'm not ,but my 80 year old mom keeps talking about getting a new one,so i'll run it by her.
how hard you wanting to work on a house? i had a guy call me this week 2bdr probably 1100 sf,it sounds like maybe 7k will buy it.it's in park city so 1950's ranch.you name it this one needs it. roof,and new sheeting,[i've been on the roof about 6months ago]sheetrock,everything. i'm not interested ,to much work for me. i would guess it's a 45-50k house cleaned up and you could spend 15-20 fixing,doing it all yourself. if you hire it done theres no wayit works.i'm getting lazy i guess. if one of the kids doesn't want it he is suppose to get back to me on it whenever.
one of those deals of it can't get much cheaper,but i'm not sure theres that much money to be made........larryif a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
Yes I'd be interested in the house Larry.Thanks for the info.