Ground Fault On A Delta

nap

I'm confusing things?

You're the one that does not understand the voltages you are reading. I do.

The fact this floating delta is used in a apartment building would be highly unlikely due to the inherent safety problems associated with a floating delta but you say it is a floating delta. I do not believe you would find a floating delta in use in the US for such a situation. It is out of place.

ou never answered my question about bonding and grounding. It should be a rhetorical question because I know how things are supposed to be but the fact there are no GF detectors in place with this system, I wouldn't take anything for granted.

on top of that, you asked this question (which I provided answers for):
and I get chastised?

Best of luck to ya cuz from what you have posted, you have no business working on this system. The problem you are having is not difficult to diagnose nor fix if you know what you are doing. I gave you the most likely answer and I get BS from you. Good luck and I hope you do not get hurt.

Eddy Current

Your problem is your trying to show everyone how smart you are instead of trying to help people. Your first three post were useless, just trying to be a smartass. After I post that mabey you should try to help intead of being an ass, you come back with questions and answers that have already been addressed.

I've solved my problem already which you would know if you read all the posts. Actually, all but one of your posts came after I posted that I had found the faults.

Just because YOU haven't seen or worked on something, doesn't mean it's not out there.

Perfect example of how you try and show everyone how smart you are and that you don't READ ALL POSTS BEFORE POSTING. I didn't answer it because the answer to your question was posted before you asked!

This whole deal has reminded me why I should stay away from these sites, too many smart-ass's hiding behind their computers who think they know everything and not enough helpfull people.

nap

No, I was trying to help you. The questions I asked were not answered. You tossed the confusing posts about ground and bond. Show me where I was being a "smartass" in my first 3 posts.

Oh, I see. Correcting you is being a smartass. My mistake for recognizing your mistakes and intitially only seeking clarification. You got offended and and somehow it became my fault you don't know what you are talking about. I see it now.

You never said you found the faults. You said you found what circuits they were in:

On top of that, you interacted with me as if you needed additional assistance, which I provided for you.

I never said it wasn't what you said it was. I said it was unlikely due to the reason a floating delta is used. That and the fact there wsa no GF indicators was merely planting a seed of doubt so that you would simply be positive you do have a floating delta. You sounded very confused and this being very easy to determine spoke volumes.



no it wasn't and still hasn't been

well, this smart ass told you more than you knew.

Like I said, good luck and I hope you don't get hurt.

rbsremodeling

This is where a joint and a couple shots of Jack Daniels would come in really handy.

__________________

acrwc10

Eddy I hope this "STUPID" back and forth with Nap does not stop you from posting your questions and findings ( I find this informative ) I would only suggest not to reply to posts that are strictly there to cause conflict.
I am wondering what the inspector said about the Ground detection, or lack there of, has he gotten back to you yet ?

nap

he already answered that. Geesh, am I the only one that doesn't read the posts?

acrwc10

In the words of Steve Martin "WELL EXCUSE ME"
I stopped reading when it just got argumentative. You can only trouble shot so much without being there is my point, so why get into useless bickering???????????

nap

Given the tenor of the thread, I got swept up in the "stupid" ( as you put it) back and forth but I guess that would be my fault.

I didn't get into bickering until my last couple of posts and that was only to defend myself from what I saw as unwarranted attacks by the person I was offering information to. Prior to that, they were for clarification of a point. Each of my questions were for a reason and had not been answered previously in the thread (regardless what eddy wants to claim). I continued to provide additional info even after OP's initial attacks.


Am I wrong for trying to help some guy that is a jackass? Probably, but I am a sucker for the disabled.

Bottom line: eddy does not understand this system and should not have been playing with it evidenced by this:

this is after replacing the fuse several times prior. That is the sign of a hack that does not know what he is doing. Continuing to throw fuses in a system that continually blows them not only is dangerous, it actually causes more damage.

You find out what the circuit powers and investigate long before tossing in another fuse. If eddy continues to work like this thread shows, I suspect he won't be an electrician (I use the term very loosely) very long as he will get hurt or killed.

Eddy Current

Agreed. And I will answer any questions from now on that are not strictly there to cause conflict, like this one for instance:

The fault on the lighting circuit was caused by a defective ballast in a exterior light post. Now that it is cleared, the fuse no longer blows but there still is a fault on one circuit in the emerg panel. Because the fuse no longer blows the building owner thinks everything is ok and does not want to spend any more money. I spoke with the inspector and he said they have to install the GF lights. Once installed we can visually show the building owner the problem is still there. I have the circuit in question locked off for now.

nap

You can take this for what its worth;

you may have more problems than you realize. In your first post, you implied the fuse was in the 600 volt side of everything. If you had a ballast popping such a fuse, you really need to look at the OCPD in the circuit for the lighting. Coordination of protection is important.

btw; how do you lock off the circuit that shows a GF, since this was indicated to be on the high side, and still have anything out of that panel running. You did say this circuit fed the transformer that runs the 120/208 panel with the outside lights. If you locked out that circuit, nothing in that panel would be working becuase you would be locking out a 3 phase breaker that fed that -panel. I am sure the owner would notice all of that not working.

.
I took that as the fuse in on the line side of the transformer.




btw: a gf on the low side of the transformer is not going to be seen as a gf on the 600 volt side. In fact, since the low side is required to be grounded, a gf on the low side had better trip the OCPD involved. If not, you have problems.

If you have a gf fault on the low side and the OCPD in the low side does not trip, you could cause an overload on the high side and trip the feeder OCPD but that would mean you have problems with the OCPD on the low side circuit.


so acrwc10, Still see this as stupid? Something is wrong here and eddy isn't getting it.

InPhase277

Is this a common thing in Canada, to feed a building with a floating delta? Seems like it would either be corner grounded or more likely wye connected. To be honest, I have never seen a utility supplied delta that was floating. They have either been corner grounded or center tapped with a high leg. The only floating deltas I have seen were derived for special equipment purposes with GF detectors, or zig-zag grounded.

acrwc10

This is where my thinking started, I doubt anyone will get an accurate read on this unless they are there trouble shooting it in person.

And to Nap yes I think getting argumentative without seeing it is a waist of time. It has been my experience that if you are rude enough and you are right , your not going to be told you were right for no other reason then, the person won't want you to have the satisfaction of being right.

nap

I don't care if I get told I am right or not. I know what I have offered is correct. I am concerned this guy does not really know what is happening and could get hurt. If that appears as being rude, I don't really care.. You don't get do overs when you are dead and 600 volts is a serious voltage to be dealing with. Little mistakes become big problems real fast.

If nothing else, I want him to think.

277. floating deltas are generally not used in my area anymore but there are still some around and yes, they are floating deltas from the POCO. .They are typically used in industrial situations. I have never seen one in a residential/commercial situation such as eddy has described this is. Doesn;t mean they were never installed as such, just that I haven't seen any.

Eddy Current

Was a common thing. This building is a 35 yr old retirement high rise owned and operated by the city. Around here there is no industrial, all commercial or residential. The city ownes around 45 high rises for commutity housing and retirement homes. Off the top of my head I know of about 6 of their buildings that have floating delta services.

I'll try to explain again. Off of the main 600v splitter there are two 15amp disco's in question. #1 feeds a 10KVA tranny for a small 120/208v panel. #2 feeds exterior light poles(ballasts are single phase 600volts). The fault on #1 (tranny) I think was there for a long time and no one noticed(no GF lights). The fault on #2 (lights) is new and every time the lights came on, a fuse in the disco (#1) for the tranny blew.

The fault on the 600v lights is strait forward but the fault on the tranny is the problem. The fault IS on the secondary side(120v hallway lights) and it blows the fuse on the primary(600v). (Now keep in mind that fuse only blows if you have both faults). Initially I thought the tranny fault (#1) was on the primary so I megged the disco, primary wires, the tranny and the secondary wires feeding the panel-all read infinite.

Why does the fuse blow when there are two faults? When I first spoke with the inspector, before he even saw it he said that if you have two seperate ground faults the smallest fuse off of the main 600v service will blow. Even if the fault is on another circuit. Anyone ever heard that before? New to me.

Nap pointed out (if you can read between all the stuff were he states I'm a hack ) that a fault on the secondary will not cause a ground fault on the primary which is true but that is what is happening here. When i turn off the 120v single pole 15 amp breaker in the panel the ground fault in the primary clears so that is the breaker that is locked off right now.

Nap you have some good points concerning this situation. Your problem is you have to constantly prove to everyone that you know everything. From my experience, people who negatively comment on other people have insecurity issues. If you just concentrated on being helpfull, you'd be a good asset to this site.

InPhase277

Because they are on different phases. The only way I can figure for the fault to appear on the 600 V side when the 120 V circuit is on is if there is a cross between the two hots. In other words, the 120 V hot and the 600 V hot must be tied to each other in some manner. I can't imagine the 120 V circuit pulling enough to load the transformer down enough to blow the primary fuse. I think there must be a physical connection.

Do you happen to know if it happens instantaneously, or does it take awhile before it happens? If you ever go back, try reading continuity between the 600 V phase and the 120 V phase, with the power off of course

p.s.: The inspector is full of bull if he thinks that any fault will blow the smallest fuse. Silly inspector! Electrical work is for pros.

Eddy Current

When both faults were there it blew right away. Once I turned off the exterior lighting, the fuse would not blow but I would still get a ground fault reading. No continuity between the primary and secondary.

Another odd thing that I noticed is that the tranny in question isn't grounded properly. X0 is bonded to the case of the tranny using 12awg wire and that's as far as it goes. The tranny is fed using metal conduit which bonds the case but there is no ground conductor from the tranny. There never was, all this work looks origional.

Also there is a fire panel fed from this tranny/120-208v panel. The building owner told me they have replaced it 3 times over the years. I suspect that the tranny not grounded properly has something to do with the problems with the fire panel and possibly the ground fault. It's an odd one for sure.

Any two faults. It sound odd but that seems to be what was happening. I always though that if you have two faults something is going to blow and it wont be a fuse. I look at it as a phase to phase short.......boom!

nap

thanks. I never said I was a nice guy. and there are no insecurity issues. If anything, superiority issues.

anyway. I'm going to read through this thread again. You most recent explanation does lay things out differently than I had read them. Won't blame you or me for that. It is what it is.

If I can help, I will.

one question and it is serious and sincere:

grrounding systems and bonding systems

Obviously the lower voltage wye is supposed to have neut bonded to a g e system, does it?. In your floating system, do you have an EGC and subsequent GE system? and is all unenergized metal bonded to it?

Just humor me on this. It's not meant to be arguementative. Just trying to get a clear clear pic.

acrwc10

Well first , I re-read through the whole thread again, and I apologize to you Nap if I it sounded like I was calling you stupid because I was not, I was saying the insults back and forth were stupid.
Second Eddy did you even read the link I posted ? It may or may not be relevant but there is some good information in it, especially about a restricking fault causing more damage in other parts of the system. http://www.mikeholt.com/safety.php?i...ems%20(2-21-2K

A thought that occurred to me is a fault on the load side of something in the system ( like after a light ) this would not trip a fuse but would still cause a fault reading.

Eddy Current

Glad to see you have a good sense of humor

No, the neutral is bonded to the tranny case and that's as far as it goes. The tranny is fed using a metal conduit which is bonded back in the electrical room.

Yes, all unenergized metal is bonded to an EGC. The electrical room is small but has two seperate feeds from the vault. One 600v delta and one 120/208 wye. Both of these systems look like they are bonded to the same EGC.
I will be back there next week to intall the GF lights so I will bring my camera, give you a better picture of what I'm dealing with.

Yes, and I sent it to my manager hoping he will send it to the customer. I've stressed the importance of fixing this right away to both my upper managment and the customer. I think a lack of understanding the problem is keeping them from acting on this right away. Also, this is social housing, our worst contract. Not sure how it works in the US but here it's a sh*t show. They never want to fix things properly, just put another band-aid on it.

Eddy Current

Actually didn't send it to my manager yet but I heard today that the customer ok'd us correcting the problem asap.