No Neutral?

[3-D]

Go HERE and sign up for a account, and it will allow you to read the 2008 NEC on line, kind of a hassle but at least it's better then not having a code book to reference, like me.

also my reply to Larry was to let him know the OP was talking about a ungrounded delta service, and there is no grounded conductor to bring to the service. So it must follow the rules in 250.24(E)

If an ungrounded service wasn't allowed, what would be requirements of that article be for then?

Thanks for the link for the online NEC. Got the sign up done, read (E). My bad.

 

[LarryFine]

Not on a ungrounded system, see 250.24(E)

and 250.24(C) only says "where" the utility supplies a grounded conductor, as pointed out in post 13

Well, reading this again . . . :

Both meterbases H-tapped to the same quadplex, but only the phases are connected? There is no 4th wire in the mast, and the messenger wire is disconnected at the pots and the masts.

. . . seems to agree with you, but then I saw . . .

The service is 480/277 wye as far as I can tell.

So, I guess I missed some of the following details. My bad, too.

 

[augie47]

hurk, What makes you think the servicwe is 480Y/277 rather than just 480 ?

 

[hardworkingstiff]

Never mind, sorry.

 

[augie47]

hurk, What makes you think the servicwe is 480Y/277 rather than just 480 ?

sorry, I didn't catch it was quotes from 2 people... Cow, I should have directed the question to you.... What makes you think the service is 480Y/277 rather than just 480 ??

 

[Cow]

Cow, I should have directed the question to you.... What makes you think the service is 480Y/277 rather than just 480 ??

Most every other 480 volt service on this farm has been wye, although I have found one to be a high leg 480 volt. You get in the habit of assuming...whoops.

I did call the power co. to verify the service voltage before my disconnect tomorrow morning. I spoke directly to one of the supervisors and he couldn't believe they had an ungrounded open delta service, so he's coming out to look at it personally. From the description I gave him, he said it must be though. Oddly enough, the pole number I gave him is supposed to have a 10kva pot with a 120/240 single phase service on it. So their records definitely aren't right...

 

[hurk27]

Well, reading this again . . . :
. . . seems to agree with you, but then I saw . . . So, I guess I missed some of the following details. My bad, too.

I agree, it is cornfusing

I saw this:

and the messenger wire is disconnected at the pots and the masts.

To which I took that the transformer tanks are not setup in a Y? and that the linemen maybe just ran what they had on the truck?

 

[LarryFine]

To which I took that the transformer tanks are not setup in a Y? and that the linemen maybe just ran what they had on the truck?

Call me weird, but if it were up to me, I think I'd rather have my service bonded to the POCO system grounded-neutral system, even for an ungrounded supply.

 

[hurk27]

Call me weird, but if it were up to me, I think I'd rather have my service bonded to the POCO system grounded-neutral system, even for an ungrounded supply.

I have seen a few dairy farms, with an ungrounded delta, with no grounded or grounding conductor coming from the pole, but I think in todays wiring, there should be at least a neutral blocker to provide any HV cross over from going to the service, with the MGN continued to the service, this wont be for fault current as that will be handled at the service, but would stop MGN voltage from appearing on the farm grounding, and provide a safe way to protect from HV being able to come from the primaries to the service.

this was mentioned in Mikes news letter on stray current on farms,

 

[Cow]

Here's the pics:

Before:

 

[Cow]

After:

My first ungrounded service so I hope I got the grounding right. Everything is bonded to the grounded electrode conductor...

 

[cschmid]

are you on the farm proper or at an irrigation pumping station on the farm?

 

[Cow]

are you on the farm proper or at an irrigation pumping station on the farm?

This is at one end of the crop farm. The disconnect I changed on the left feeds a small 15hp submersible pump that pulls from an underground spring, the one the right controls an irrigation pivot.

 

[cschmid]

so there really is no need for a GC and what you probabully have here is a bearing out of a motor and the begining of some failure or what I would first do is inspect every connection point as you can see that could be a problem. At the same time I would also inspect the motors as well for physical damage. I forgot what part of the ciruit you said was triping, and did not go back and look it up.

 

[Cow]

After I repaired this service a couple days ago I spoke to the customer again about the problem. He said the breaker made a sizzling sound when you reset it, which he hadn't mentioned before.

I drove by the pump again today to throw some labels on it for inspection and it was still running like a champ. I'd say all is well.

 

[hurk27]

After I repaired this service a couple days ago I spoke to the customer again about the problem. He said the breaker made a sizzling sound when you reset it, which he hadn't mentioned before.

I drove by the pump again today to throw some labels on it for inspection and it was still running like a champ. I'd say all is well.

Looking at all the dirt and dust, in these panels, I would say the breaker might have some on the contacts, which might be single phasing or be causing it to heat up, just not every time.
With 3 phase you only have to loose one to cause a problem.

 

[cschmid]

well you did good job on that old dirty negelected service.