POCO finally believed me

[mxslick]

Since it was the same line at one foot intervals that seems to reinforce my theory that there was some sort of defect or damage to that line. :grin:

And that the load on that leg was heavier than the other. :grin:

 

[kevin]

Jim,

I am not sure if you ever got an answer on your conductor ampacity question or not. I work at a POCO and here is what my book says:

#2 Triplex 600V - allowable ampacity 171 Amps (This is the Southwire allowable ampacity at max operating temperature of 194 degrees F in open air blowing at 2.05 miles per hour)

The conductor should have (2) seven strand #2 AAC conductors and (1) seven strand #4 AAAC neutral.

I can give more stats on the conductor if you would like; but I think this gives you what you originally wanted. Hope this helps.

My Southwire data sheets show the following ampacities for Triplex Service Drop Multiplex Cable with ACSR Neutral Messenger, 2AWG, 7 strand "Conch": 150A for Vulcanized Interlinked Polyethylene (VIP-90degC) insulation, and 120A for Polyethylene (POLY-75degC) insulation.

Regardless of the published ampacities, the circuit ampacity, even for overhead spans, is also subject to the terminal temperature limitations in 110.14(C)(1). The typical splice connectors used in this type of installation are almost always rated 90degC, and Table 310.17 (Single-Insulated Conductors...in Free Air) can be used in lieu of the normally used Table 310.16 (...Three Current-Carrying Conductors in Raceway, Cable...). For such a scenario the allowable ampacity for the splices is 150.

 

[Jim W in Tampa]

Am waiting for them to show up and change drop.
What i did arive at is there are 8 of us on this 50 kva transformer. I can not understand how we have not managed to blow the top off it. Thats about 6.2 kva per dwelling. Somehow that seems just flat out crazy.
I did suggest to engineering that they drop me from another transformer ,same 50 kva that only has 4 on it now and is 80 feet shorter run. Will let you all know what happens. Being nice with them has not seemed to help. 5 days later still not fixed. If you look close at the 1 picture you can see bare wire ready to touch messenger. If it rains good chance game is over. We are talking maybe 1/8 of inch. If not changed before Saturday i will be taking legal steps. Is a chance i am unbalanced but not by that much and sure can't risk trying till wire is changed. I will then balance with loads i have on a Saturday night as close as i can. Thing is most of my large loads are 240. Is chance i have the 120 volts AC units unbalanced. That i can easily fix but lets keep in mind i did not trip my 200 amp main. I will be posting actual amp readings. Doing a load calc as Bob suggested is almost impossable because many of the normal loads like DW, SA, washers dryers are not in the picture on Saturday nights. It is forcing me to upgrade by directory that is long ago been wrong. So yes Jim might be part of blame. What upset me most is the lights on dance floor pole went down.

 

[Jim W in Tampa]

It's fixed. And just in time. I had not noticed but the neutral from the arcing was down to 2 strands and ready to break. The wire itself was ok but was hot enough to make bubbles that were in picture. He ran another #2 triplex to street, rest of run was 1/0
Time will tell and I will be balancing my load

 

[mivey]

#2 Triplex 600V - allowable ampacity 171 Amps (This is the Southwire allowable ampacity at max operating temperature of 194 degrees F in open air blowing at 2.05 miles per hour).

I have 2 tables: 173 & 180 amps.

Curious Varczar as to what size you would suggest the run. Run is 340 feet and service 200 amp main SQ D 22,000 air rated breaker. Do allow the Fl. heat factor in summer

250 or 340? You have said both. Of more interest would be the home size, if it is total electric or not, A/C & heat load. Even of more interest is why you have not had a big issue with flicker and voltage drop.

It's fixed. And just in time. I had not noticed but the neutral from the arcing was down to 2 strands and ready to break. The wire itself was ok but was hot enough to make bubbles that were in picture. He ran another #2 triplex to street, rest of run was 1/0
Time will tell and I will be balancing my load

#2 might have been marginal amp-wise given your load, but certainly seems too small for volt-drop issues.

Did you take any amp readings?

 

[iwire]

Regardless of the published ampacities, the circuit ampacity, even for overhead spans, is also subject to the terminal temperature limitations in 110.14(C)(1).

The NEC does not apply to those conductors or terminations.

 

[kwired]

..What i did arive at is there are 8 of us on this 50 kva transformer. I can not understand how we have not managed to blow the top off it. Thats about 6.2 kva per dwelling. Somehow that seems just flat out crazy.

Transformer is not overloaded during one of your parties because all your neighbors are at your place and their homes are not using much power.

 

[Jim W in Tampa]

Transformer is not overloaded during one of your parties because all your neighbors are at your place and their homes are not using much power.

Nope they don't like what i have going but i am legal.
Not had time to balance anything yet.
If or should i say when i melt the new drop maybe i will get 1/0
What i can not understand is why the top has not blown off the transformer. My calculated load is about 20 kw of that 50 kw transformer. Winter will be interesting because believe it or not in main bar area i will be running AC not HEAT
People are about 1,000 btu each. Me and my AC friend spent hours calculating how much we need and duct sizes. and make up air .
I do exspect more outages.

Sad note another poco company TECO lost a linesman last week. Awfull way to go and had wife and kids.

 

[mivey]

What i can not understand is why the top has not blown off the transformer. My calculated load is about 20 kw of that 50 kw transformer.

20 kW in winter or summer? For how long of a period? That 50 kVA can handle 150 kVA for brief spurts, and may start routinely peaking at 70 kVA before even being considered for a change-out:

Per-unit overloading for normal transformer life:
Over-load Hrs: per-unit for 50%, 70%, 90% pre-loading
0.5 hrs: 1.89, 1.77, 1.59 pu
1.0 hrs: 1.60, 1.54, 1.40 pu
2.0 hrs: 1.37, 1.33, 1.24 pu
4.0 hrs: 1.19, 1.17, 1.12 pu
8.0 hrs: 1.08, 1.08, 1.06 pu

Even if pre-loaded to 50 kVA then over-loaded to 77 kVA for an hour, you only lose 0.10% of the transformer life. Don't forget that some of your 20 kVA of load is cycling on and off also. The older transformers seem to be a lot tougher too.

 

[hurk27]

Our POCO will make us fill out a load form and we have to sign it, which locks us in on what we request, they use it to determine many things not just the drop and transformer, but also primary's feeding this transformer, substations capacity, from what I been told is their computers will use this info to even calculate the extra load all the way back to the generator feeding our area. there is a lot of capacity management that has to be done even when adding one service load to the whole system, this management is very crucial to over all system stability and future loads being added. but they do have their faults as they are human as we are, and in one particular case come to mind, was about 6 years ago I had put in a request for a 200 amp 120/208 Y seven jaw meter service at a trucking shop for a 10hp 3-phase air compressor, the existing service was a 400 amp 4 gang meter pack with 4 100 amp services for offices and garage lights in each unit, not enough to add a rotor phase converter to pick up this new load, they had me fill out the load sheet to which I only put this air compressor on it, which had a 28 amp fla, so their engineer used this and figured a #6 drop even though it was about 200 feet from the transformer to weather head, the voltage drop at start up was so severe that the motor would just stall and eventually burned up, of course the workers would just keep resetting the overloads, and we found out the motor was a mistake by the factory which it was rated for 230 volts not 200 volts, all of which I had no idea because we set the service per specs and went home, in any case even with the correct motor the voltage would drop to about 165 volts at startup, so after several calls to the POCO as the original engineer would not budge on the drop and kept saying this is all we were going to get, I finally was able to go over her head after calling our state utility commission and get another engineer out of another town, and he could not believe she didn't take into account the voltage drop, and the fact that other loads will most likely be added to this panel, so he ordered the drop to be changed out to a 1/0 1/0 1/0 #2 and we added the 100 amp service to this panel also to eliminate the other meter bill, never had a problem since and this service has two welders and another 10 hp 3-phase air compressor that has been added to it.

I attach a PDF copy of the load sheet we have to fill out so you can see what it ask for:

 

[Jim W in Tampa]

My 20 kwh is an average per hour over about 7 hours. Very sure i hit some peaks. Rest of week my demands are very low. All we can hope for is that the other 7 dwellings are not having parties like mine. Not much more i can do beyond warning them. Guess they prefer to get 911 calls at 1 AM to come fix things. Even after there own man told them we need 1/0 they ignored it and replace it with same #2 triplex. Was plenty of evidence that we over heated and are melting the drop. Load can not get much lower for this 6 hours and really is not all that high for a 200 amp service.
Load actually gets lower in winter time as we do not nead heat as we have plenty of body heat.

 

[LarryFine]

Our POCO will make us fill out a load form ...

I attach a PDF copy of the load sheet we have to fill out so you can see what it ask for:

This is the Dominion Power Load Letter:

 

[hurk27]

This is the Dominion Power Load Letter:

very similar.
I see they still offer the 4-wire delta where ours don't, and we can get a ungrounded delta or a grounded B, and we have a few unusual configurations such as the 240/139 Y, the neutral is just for fault current path.

I'm using a 240/139 Y on a lift station that has no neutral loads, for 120 volts there is a 3kva transformer in the main control cabinet, the generator is configured the same. just 3 phase conductors and the EGC run from the transformer. Never had one like this and for the life of me can't figure out why it was specked out like this, as I would have expected to see deltas on motor loads.:roll:

 

[mivey]

My 20 kwh is an average per hour over about 7 hours. Very sure i hit some peaks. Rest of week my demands are very low. All we can hope for is that the other 7 dwellings are not having parties like mine. Not much more i can do beyond warning them. Guess they prefer to get 911 calls at 1 AM to come fix things. Even after there own man told them we need 1/0 they ignored it and replace it with same #2 triplex. Was plenty of evidence that we over heated and are melting the drop. Load can not get much lower for this 6 hours and really is not all that high for a 200 amp service.
Load actually gets lower in winter time as we do not nead heat as we have plenty of body heat.

They must be thinking about load amp capacity only. I still don't see why the voltage drop is being ignored as that would seem to be the bigger issue.

 

[Jim W in Tampa]

They must be thinking about load amp capacity only. I still don't see why the voltage drop is being ignored as that would seem to be the bigger issue.

The first 240 feet is 1/0 last 100 feet is #2
Will be balancing loads this week. Checked early Saturday and at 1 point i had about 100 amps on A and 150 on B. Did move a few loads but really need to locate what all is on B
That likely caused a lot of the trouble.
Voltage drop seems to be within range.
I have 1 main panel and 4 sub panels so first step is make same leg A in all panels. Till now never seened it to matter.

 

[readydave8]

Jim: So was this week's party a sucess and therefore you're just getting up?:grin:

 

[Jim W in Tampa]

Jim: So was this week's party a sucess and therefore you're just getting up?:grin:

Well the lights stayed on guess that was good.
Party must go on.
Will be looking into maybe getting hot tub on to propane to reduce part of the load.

 

[mivey]

Well the lights stayed on guess that was good.
Party must go on.
Will be looking into maybe getting hot tub on to propane to reduce part of the load.

Well how about setting the beer down long enough to get us some amp & volt readings. My curiosity is up. :grin:

 

[Jim W in Tampa]

Well how about setting the beer down long enough to get us some amp & volt readings. My curiosity is up. :grin:

Will see what i get for readings after i get this balanced out. Will monitor both lines voltage next Saturday. I do enjoy fireworks but prefer not to lose lights over 1 big kaboom.
Will take time to get everything logged as to what breaker and exact amps.
Simply no time during parties to be watching amps as i am to busy watching the girls at the pole. At this point i believe i just had far too much on one 1 leg. Will keep you posted.

 

[hurk27]

as i am to busy watching the girls at the pole. At this point i believe i just had far too much on one 1 leg. Will keep you posted.

Ok which "amps" or-----:roll: