Doubled through CT's

[Minuteman]

Customer calls me about his electric bill being real high. His Hot Tub store is in the east half of a building. There was only one meter, but someone moved into the west half in November. They separated the wiring and added a meter, making it Suite B.

His electric bill from November and December are almost 3 times that of the last 3 years for the same 2 months. He called the PoCo, and they told him to have an electrician meet their service guy there.

When we opened the CT can, this is what we found.

(The neutral and the CT wiring are left out for clarity)

Power comes into the CT can from the bottom, through the CT's, to a block connector. One conductor leaves the block connector and goes to the Suit A conduit. The other conductor leaves the block and goes back through the CT and to the conduit for Suite B's meter.

If the Suite B conductors went through the CT in the opposing direction, the fields would cancel and on to the B meter with no problem. However, since the conductors are travel the way they do, the CT re-reads the current and is re-recorded on Suite A's meter. The PoCo service guy agreed, and was to come back after the store closes tonight to make the change.

My question. Would the effect of all this actually give PoCo triple billing for the usage of Suite B? Once for the recording on the standard type meter for Suite B. Twice for the doubling effect of going through Suite A's CT meter?


CORRECTION: I just noticed that I drew the Suite B blue conductor wrong. It also leaves the block and goes through the Ct from the left to the right. Not as shown.

 

[quogueelectric]

Looping the wire through twice as shown will show twice the amperage assuming the cts are equal. It is fairly common in motor control ckts to loop through cts to match available equipment to motors served. For example if you had a motor that drew 10 amps and only a 20 amp ct heater section was readily available you could just loop the motor leads around the cts twice and set the ols for twice the load. So unless one ct is a different ratio which it may very well be either the other electrician was making due with the parts that he had OR the sneaky bastard was trying to raise the electric for the other tennant.

 

[wireguru]

OR the sneaky bastard was trying to raise the electric for the other tennant.

or maybe it was a resi guy that did it, and thought 'I better run my wires through those bushings like the other guy did'

 

[quogueelectric]

or maybe it was a resi guy that did it, and thought 'I better run my wires through those bushings like the other guy did'

He has so many wires through that ct now gotta derate 50% Bundling right? Only the blue phase is doubled.

 

[LarryFine]

Yep. He's paying for his own power at 1x, and for the other tenant at 2x.

 

[KentAT]

Yep. He's paying for his own power at 1x, and for the other tenant at 2x.

I'm no CT pro, but based on the responses of others, A pays for A, B, and B again. B pays yet another time for B separately. So you are correct that the Poco collects 3x what it should for B (but 2x of that is being paid by A as LarryFine mentions). Should be a nice refund/credit for A.

Kent

 

[LarryFine]

Added thought: If you plan on pursuing this legally (which you should) and seeking a fair settlement, you should take several clear photographs of how this is wired before it's fixed.

 

[Minuteman]

Got 'em Larry.

Also, the A guy had looked at his Nov/Dec bills and says, "I figure they overcharged me by at least 25000 KW, but how do I prove it? "Easy", says I, "His new meter is reading 12460 right now"! Then I took a picture of that too. :smile:

 

[hardworkingstiff]

A's true power bill = A meter - (3 * B meter)

Total true power bill = A meter - (2 * B meter)

 

[tshea]

Doing this work would require a permit and inspection. Why do I think neither happened. I am also guessing a licensed qualified electrician did NOT do the work.

I once saw a CT installation where the sparkie had to re-route some 500mcm wire through CTs. He had to extend the wire, install a j-box, and 2-piees o 3" EMT. Apparently he was side tracked and in one pipe he had 4 wires and the other 2 wires.
The first pipe was very warm! He lost money on that job. Had to come back and make it right.

 

[Minuteman]

I just pulled up the Permit on the AHJ's web site. I know of the EC that did the work, don't know them, haven't heard anything bad about them though. The service inspection passed on 10/20/08, C/O on 10/22/08. I've known the inspector for years, we tooled together before he became an EI. Don't know why he missed it.

However, tying into PoCo's CT can here is PoCo's work. It had a PoCo padlock on it.

 

[Minuteman]

 

[Minuteman]

Sorry dude, I left my real camera on my desk that day.

 

[luckyshadow]

In my neck of the woods - the only person doing ANYTHING in a POCO CT cabinet is the POCO. Maybe the POCO service guy should find out who in their company doesn't have a clue