need to know whats wrong

[dlgoold1@gmail.com]

50 kva transformer, 106' 1/0 al xlp neritina triplex southwire then spliced, to 80' 2/0 al xlp underground to my meter 200 amp service. the neighbor served by the same 1/0 al xlp, spliced to 50' #2 al triplex service drop to meter 100 amp service. this is one branch curcit for two homes in south carolina there is a diversity factor of .85 per cpw being the utility company.

 

[Dennis Alwon]

I am re-opening the thread as the op just wants to know what we think of the configuration. He thinks it is unsafe but the utility says it is fine. Since this is not a how-to or diy question I am allowing it.

 

[iwire]

It is fine, nothing to worry about in the least.

 

[brian john]

Do you have light flicker?
Do you have any low voltage issues?

Do you have any issues?


If so the utility most likely won't do anything to help so you have to live with it.


If you do not have any issues you still have to live with it.

But as installed there is not issue.

 

[jumper]

Sounds like typical residential POCO install.

What does "diversity factor of .85 per cpw" mean?

 

[Hv&Lv]

I agree with the rest of the crowd, nothing wrong with that installation. In fact, I am surprised that there is 1/0 in the span at all considering the distance, and the 50 kVa pot is oversized if there is only two houses on it, especially in SC.(winter loading)

 

[Hv&Lv]

What does "diversity factor of .85 per cpw" mean?

I was curious about that too. I thought the diversity factor would be closer to 1.5 or higher with two houses.

 

[jumper]

I was curious about that too. I thought the diversity factor would be closer to 1.5 or higher with two houses.

Actually I am trying to figure what diversity factor the OP is talking about period, It might something you POCO guys look at, but me and my NEC are clueless.

As far as OP worrying about what POCO does in a resi install, I say tell HOs to not worry about it. If it breaks or is wrong, POCO has to fix it, so not a problem.

 

[Hv&Lv]

Actually I am trying to figure what diversity factor the OP is talking about period, It might something you POCO guys look at, but me and my NEC are clueless.

As far as OP worrying about what POCO does in a resi install, I say tell HOs to not worry about it. If it breaks or is wrong, POCO has to fix it, so not a problem.

the house demands would be 42 kW, and the XF is 50 so 42/50 =.84
I would expect the house demands to be 42kW, and the xf to be 25 so 42/25= diversity factor of 1.68. Not everything in the house will run at once, except on cold load pickup after an extended outage. Of course, the XF can double capacity for a couple of hours and be fine. The constant switching of loads in a house or houses is what we look at when sizing. I have seen (5) 2500 sq.ft. houses ran from a 25 kVa transformer for a couple of years. We changed it when the internal fuse blew after a week of 90+ temperatures. Put a new fuse in it and set it somewhere else to serve 1-2 houses
houses..

Rule of thumb around here, 1 house w/ electric heat and air conditioning= about 12-15 kW

 

[jumper]

the house demands would be 42 kW, and the XF is 50 so 42/50 =.84
I would expect the house demands to be 42kW, and the xf to be 25 so 42/25= diversity factor of 1.68. Not everything in the house will run at once, except on cold load pickup after an extended outage. Of course, the XF can double capacity for a couple of hours and be fine. The constant switching of loads in a house or houses is what we look at when sizing. I have seen (5) 2500 sq.ft. houses ran from a 25 kVa transformer for a couple of years. We changed it when the internal fuse blew after a week of 90+ temperatures. Put a new fuse in it and set it somewhere else to serve 1-2 houses
houses..

Rule of thumb around here, 1 house w/ electric heat and air conditioning= about 12-15 kW

That's cool info, I had no clue about how POCO sizes resi XFMRs.

 

[kwired]

I am suprised the transformer is 50 KVA for supplying only two homes with 100 and 200 amp services. Even if the 200 amp service had electric heat most of the time you would only see a 25 KVA and sometimes maybe 37.5 KVA.

I am more concerned with voltage drop than transformer size. You will have voltage drop on an undersized transformer but the length of conductors is still a bigger problem. Voltage drop will be most noticeable when motor loads are starting - especially the AC compressor.

Otherwise it is very typical installation, and you likely will not get POCO to do anything to make it better, unless you want to pay for some or all of what is done.

 

[dlgoold1@gmail.com]

thanks for the replys. the problems i been having are v-drop, and emi. the 2 1/2 ton ac unit switching sounds like a dc-10 on start up. also frying the tv's cordless phones blue-rays & computers .they wont upsize wire unless i pay 1500.00 and money is tight.

 

[Hv&Lv]

thanks for the replys. the problems i been having are v-drop, and emi. the 2 1/2 ton ac unit switching sounds like a dc-10 on start up. also frying the tv's cordless phones blue-rays & computers .they wont upsize wire unless i pay 1500.00 and money is tight.

If you have called to POCO to diagnose the problem already, and it sounds as though you have, I would use the $1500 to hire a competent electrician to look into your problem. Don't know where the EMI diagnosis came from, most of those are from inside the home. It is almost impossible to diagnose the problem over this forum, and I doubt the moderators would stand for anyone trying.

If an electrician can show that the problem is on the POCO side, then save the receipts for the burnt appliances...

 

[George Stolz]

If an electrician can show that the problem is on the POCO side, then save the receipts for the burnt appliances...

...and there's little hope of that.

I agree with your advice, the original poster needs to hire an electrician to determine what has transpired in the house.

 

[hurk27]

With burnt up appliances I would be suspecting a bad neutral connection over just a voltage drop issue, and as others have said any good electrician should know how to isolate this type of problem out to the point that its either ahead or after the meter or utility point of connection.

Let me ask you this, have you notice any incandescent lights (if you have any) getting brighter when a heavy 120 volt load comes on? (240 volt loads don't load the neutral) if so then your problem is a bad or lost neutral connection and needs attention ASAP.