Quick POCO story

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chris kennedy

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
Office gets a call yesterday about multiple pieces of equipment not working at large country club served by Florida's largest provider. The owner of our company goes there and gets odd voltage readings and determines it a POCO issue.

I get sent there this morning for same issues and find I have lost high leg of a 240/120 open delta. I report my findings to clubs general manager and he states POCO was there 5pm yesterday and said all is well. I tell them to call POCO again.

I go outside and poke around, all looks OK in POCO vault, so go a couple hundred feet out to pole. Got 2 primaries with 2 cut-outs on the pole that go underground to vault. Both cut-outs are closed but there is a small piece of wire hanging out the bottom of one fuse.

I'm out there getting pics of fuse and pole # when GM comes out and says POCO doesn't believe me. We go back into his office so he can send them the pics I took. There he shows me the E-mail of the POCO linemans report from previous night. The report shows L1,L2,L3 to N voltages all right around 120V.

Here's a clue lineman, with all breakers closed on a partial power call you just might want to check L-L voltages also.

3 hours later POCO replaces fuse and I'm back on line.

(sorry, not such a short story after all)
 
I have had the same issue numerous times with our local power company . I call them and tell them it is a bad neutral and I tell the customer to make sure they test with a load on. The last guy said you don't need a load to test... I call up raising hell and they send somebody back out who immediately said it was a bad neutral---they had to dig up the front yard to repair it.

I don't understand why these guys are not trained on how to trouble shoot a bad connection especially on the neutral. Honestly I bet this has happened over 5 times to me over the years
 
chris kennedy said:
I would guess all of POCO's "A" Teams are up north right now.

You still have power at your house Dennis?
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Few areas around here are out but we have been pretty lucky lately. We have developed an insurance plan that really helps to keep the lights on. Whenever there is a threat we fill up large containers with water (we have a well) and it's a guarantee the lights will not go out.... Haha.

Obviously you still have power but some areas around here are getting bombed with rain. Fayetteville has had 16" already and that is after 10" last week... We have only had about 4" but there is wide spread flooding.

Supposed to go dancing tonight but everyone I know is backing out... I think I'll go anyway
 
gadfly56 said:
Pencil whipped the report?
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That was my thought, tho I havent troubleshot enough high leg delta setups to know if 120V from another line could be induced and read on an open high leg. L-L ought to reveal that there is just single phase, especially given the nature of the problem, which would be no 3ph loads work and only 240V single phase loads work across AC phase.

I'm not a lineman but even I know to look at the fuse on the pole mounted xfmr that serves my house if power goes out.
 
JFletcher said:
That was my thought, tho I havent troubleshot enough high leg delta setups to know if 120V from another line could be induced and read on an open high leg. L-L ought to reveal that there is just single phase, especially given the nature of the problem, which would be no 3ph loads work and only 240V single phase loads work across AC phase.

I'm not a lineman but even I know to look at the fuse on the pole mounted xfmr that serves my house if power goes out.
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If the secondary line supplying the high leg (C) opened then conducted voltage trough a line to line load connected ONLY to A and B or to A and C would put 120V on B. If equal loads were on both sides, then you would read zero to the neutral instead.

If the primary of the stinger pot of an open delta (supplying BC) opened then the zero volts across the secondary could leave B at the same potential as C, namely 120V to neutral as long as there was no load on B.
 
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GoldDigger said:
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If the primary of the stinger pot of an open delta (supplying BC) opened then the zero volts across the secondary could leave B at the same potential as C, namely 120V to neutral as long as there was no load on B.
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It'd probably approach 120V even if there were a load on B. B to A would be almost the same as C to A (240V); unlikely any B to N loads; and B to C load would reduce impedance B to C, so it would assist rather than detract.
 
GoldDigger said:
If the primary of the stinger pot of an open delta
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Yup

Smart $ said:
It'd probably approach 120V even if there were a load on B.
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More likely what I had. I know this facility well and even though the 3Ø safety switches for the RTU's and refrigeration equipment were in the open position, there are 1Ø 240V resistive loads connected across C. (coffee makers, steam tables ect all in violation of 240.85)
 
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