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Old 05-20-2010, 11:34 PM   #1
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Default High voltage current on neutral

Do any of you see the possibility of the hi voltage primary current in a residence transformer getting into the neutral circuit of the residence?

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Old 05-20-2010, 11:52 PM   #2
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Uh, maybe?

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Old 05-21-2010, 08:38 AM   #3
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Are you talking about the primary current being shorted to the secondary?
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Old 05-21-2010, 11:04 AM   #4
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Do any of you see the possibility of the hi voltage primary current in a residence transformer getting into the neutral circuit of the residence?
Once again in English?
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Old 05-21-2010, 11:43 AM   #5
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Yes, Ask the question again, but think first this time.
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Old 05-21-2010, 12:43 PM   #6
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I guess that's the key.Think in English. Since the primary of the service transformer is often grounded via a rod at the pole and the secondary is grounded at the pole via a rod, they are essentially connected. At the service you are providing a grounding electrode via a rod or water pipe and bonding the neutral to it. If you need more information than that to come to a conclusion then I'm not the only one that needs to think it through...in English.
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Old 05-21-2010, 12:46 PM   #7
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Are you talking about the primary current being shorted to the secondary?
That is a possibility, however that is not what I am talking about. At least you came up with a possible solution rather than hurl an insult as to its wording. Remember, if you respect others usually they will respect you. Thanks.
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Old 05-21-2010, 12:53 PM   #8
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Quote:
Originally Posted by RIVETER View Post
That is a possibility, however that is not what I am talking about. At least you came up with a possible solution rather than hurl an insult as to its wording. Remember, if you respect others usually they will respect you. Thanks.
I am the first to agree with about the insults however, insulting back does not usually help your cause. Let's all be friends and kiss and make up.

Now to answer your question-- I would if I could but honestly I am not sure what you are asking. Are you thinking the primary in a transformer can accidentally make contact to the neutral on the secondary side thus causing high voltages on the neutral?
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Old 05-21-2010, 01:35 PM   #9
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To answer what I think you are asking,

yes it is possible but only if the ground at the pole is broken or cut, and possibly even the one at the/each service supplied from that xfmr.
Because as you say, they are tied to the same ground at the pole.

But if the GEC was cut at the pole, the ones at the service drops should take over the grounding.

If it was only one service of the xfmr then yes all the current would be present at the Neutral. If you were doing a service change and cut the Noodle, you could get seriously hurt. Even though you had already cut the hots.
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Old 05-21-2010, 02:20 PM   #10
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Quote:
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I am the first to agree with about the insults however, insulting back does not usually help your cause. Let's all be friends and kiss and make up.

Now to answer your question-- I would if I could but honestly I am not sure what you are asking. Are you thinking the primary in a transformer can accidentally make contact to the neutral on the secondary side thus causing high voltages on the neutral?
Okay, we can make up. But no tongue this time. Actually, I was not thinking about a primary to secondary short circuit at the transformer but you are probably correct. I guess it could be a hi resistance short there.
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Old 05-21-2010, 03:14 PM   #11
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Quote:
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That is a possibility, however that is not what I am talking about. At least you came up with a possible solution rather than hurl an insult as to its wording. Remember, if you respect others usually they will respect you. Thanks.
I get NO RESPECT! I'm used to it though!
I am the first to admit I don't know everything. I can handle looking stupid here...but not in front of a customer!
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Old 05-21-2010, 03:43 PM   #12
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I get NO RESPECT! I'm used to it though!
I am the first to admit I don't know everything. I can handle looking stupid here...but not in front of a customer!
I believe Riveter was giving you thanks and a compliment.
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Old 05-21-2010, 03:57 PM   #13
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I believe Riveter was giving you thanks and a compliment.

I know he was. I just wanted him to know I ask stupid questions(his question wasn't stupid) I probably should know the answer to at times. I can handle the ribbing I get as long as I learn what I didn't know. Residential electricians know things by heart that commercial electricians do not usually know.
I do a mixture of both types of work and am still learning. I think I always will be.
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Old 05-21-2010, 04:07 PM   #14
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Quote:
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I guess that's the key.Think in English. Since the primary of the service transformer is often grounded via a rod at the pole and the secondary is grounded at the pole via a rod, they are essentially connected. At the service you are providing a grounding electrode via a rod or water pipe and bonding the neutral to it. If you need more information than that to come to a conclusion then I'm not the only one that needs to think it through...in English.
I think you better draw it as we all know that the primary and secondary conductors are connected via a grounded conductor.

And the fact it was not just me that does not understand what you are asking should tell you something.
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Old 05-22-2010, 01:04 AM   #15
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I'll add my own stupid question, since I am not a lineman. In my area, all I ever see is delta connected primarys and wye secondaries. The secondary wye side gets a ground to neutral bond at the derived neutral connection point of the transformer, and that gets run down to a ground rod every few other poles. But where does this "primary" grounding happen? Do they provide wye primary lines on the mainland? If so then Riveter's question makes a bit of sense, but I not familiar to this type of primary service.
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Old 05-22-2010, 01:57 AM   #16
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Let's say an evil electrician set it up. It would require disconnecting the neutral from the POCO earth. Then juicing it up off of one of the transformer lugs.

Wouldn't the GEC melt? Unless the current was somehow limited by the failure/evil plot.

There would probably be lots of melting. Lots of damaging backfeeding through equipment. What a mess that would be.

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Old 05-22-2010, 04:47 PM   #17
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The problem I have is that transformers are about voltage, not current and the neutral is determined by the hookup, not the transformer. But, I really don't know how the PUCOs wire their transformers regarding the primary side and the center tap of the secondary. The secondary center tap is the grounded electrode at the house side of the service, but is the primary also center tapped and grounded or is one end of the primary grounded?
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Old 05-25-2010, 03:48 PM   #18
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I'll try this again. After re-reading my post I can see the confusion. My concern was that if the utility grounds the primary via a rod at the pole and they do the same on the secondary side at the pole and then we drive a rod or some other type of electrode such as the water pipe system and then tie the ground to our circuit conductor(neutral), with so many connections to ground I was thinking about the possility of the primary of the transformer finding a way through the water pipes. It was one of those days when I was thinking about stray voltages and why they are caused. They are caused by stray currents and I thought I'd ask.

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