Power Flux (Dimming)

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swami69

Member
Location
Benton, AR
OK, here is my problem. I have a home owner in a newly constructed house. They are building a new house right next door. The owner is seeing a power flux (dimming) in the lights whenever any of the following occurs:

- she turns on the A/C in her house
- she turns on the washing machine in her house
- the compressor next door kicks on (for their nail gun and/or other tools)

The compressor next door is hooked up to a temporary next to the street. She says she's called the local utility company and that the house is getting plenty of power. They may have even upgraded the line from the street to the house in an attempt to fix the problem.

Any thoughts on what the problem might be?

Thanks.
 

jumper

Senior Member
Lights dimming when A/C kicks on is common.

Washing machine would be unusual, unless the lights were on the same circuit-still a bit odd. Did you actually observe this?

Depending on the size of the compressor and if the 2 houses, or more, share the same transformer, possible.

POCO never upgrades anything unless they have to. They max out their equipment all the time.
 

swami69

Member
Location
Benton, AR
Lights dimming when A/C kicks on is common.

Washing machine would be unusual, unless the lights were on the same circuit-still a bit odd. Did you actually observe this?

Depending on the size of the compressor and if the 2 houses, or more, share the same transformer, possible.

POCO never upgrades anything unless they have to. They max out their equipment all the time.
I had someone go out and look and there was a slight dimming when either the washer or dryer kicked on (they only observed the light in their utility room), but regardless, there was a flux.

These two houses do share the same transformer. I believe there are currently 5 houses on it right now.
 

stickboy1375

Senior Member
Location
Litchfield, CT
OK, here is my problem. I have a home owner in a newly constructed house. They are building a new house right next door. The owner is seeing a power flux (dimming) in the lights whenever any of the following occurs:

- she turns on the A/C in her house
- she turns on the washing machine in her house
- the compressor next door kicks on (for their nail gun and/or other tools)

The compressor next door is hooked up to a temporary next to the street. She says she's called the local utility company and that the house is getting plenty of power. They may have even upgraded the line from the street to the house in an attempt to fix the problem.

Any thoughts on what the problem might be?

Thanks.
It's called voltage drop, and most likely a power company issue, from what i've read, women are more susceptible to noticing such conditions.
 

jumper

Senior Member
It's called voltage drop, and most likely a power company issue, from what i've read, women are more susceptible to noticing such conditions.
Probably because most women are observant of there surroundings and we are clueless-unless it is electrical.

I sat in the bank for two hours with my wife discussing CDs, mortgages, etc and signing papers with a financial manager. When we walked out she asked "Well. what do you think?'

I said "The SJO cord feeding the emergency light was a violation off 400.8", I thought she was gonna kill me.:) I had not listened to one thing they talked about.
 

stickboy1375

Senior Member
Location
Litchfield, CT
Probably because most women are observant of there surroundings and we are clueless-unless it is electrical.

I sat in the bank for two hours with my wife discussing CDs, mortgages, etc and signing papers with a financial manager. When we walked out she asked "Well. what do you think?'

I said "The SJO cord feeding the emergency light was a violation off 400.8", I thought she was gonna kill me.:) I had not listened to one thing they talked about.
I've walked into things in stores staring at the ceiling myself. :)
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Never heard it refered to as power flux. What size pot is feeding the house(s)? What size wire is feeding the house(s)? How about the length? This is where an old analog volt meter comes in handy... Measure the drop before you get the POCO involved. Have all your answers in line before they ask the questions, that way, you will get more from them.
 

jumper

Senior Member
Never heard it refered to as power flux. What size pot is feeding the house(s)? What size wire is feeding the house(s)? How about the length? This is where an old analog volt meter comes in handy... Measure the drop before you get the POCO involved. Have all your answers in line before they ask the questions, that way, you will get more from them.
I'll bet a 1/2 dozen donuts most POCOs could care less if lights dim.

I think you work for a POCO and might care, but anybody else...nope.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
I'll bet a 1/2 dozen donuts most POCOs could care less if lights dim.

I think you work for a POCO and might care, but anybody else...nope.
I have the hardest time getting some of the service guys to hang something bigger than a 10 or a 15 kVa pot for two houses, much less one. You try to explain the amperage at 100% and 200%, they fail to see the problem. I have been trying to get some information on transformer voltage regulation vs loading to see how far an XF can be loaded before the output voltage starts to fall off.
 

hurk27

Senior Member
I have the hardest time getting some of the service guys to hang something bigger than a 10 or a 15 kVa pot for two houses, much less one. You try to explain the amperage at 100% and 200%, they fail to see the problem. I have been trying to get some information on transformer voltage regulation vs loading to see how far an XF can be loaded before the output voltage starts to fall off.
I have a trailer park that has a 400 amp 240 volt grounded B delta that used to feed the pump/filter building before they switched to city water, they had fed the old office/managers house which is now just the main office off a little 10kva transformer over the years street light, lighting for a post office, landscape lighting, and all the 120 volt loads still in that old pump building are on this poor old transformer, while its only rated for 41.7 amps it has about 120 amps of load on it, it been that way I guess for over 7 or 8 years, you can fry an egg on it, but as far as voltage drop goes at the full load of 120 amps its running about 204 volts between legs and 102 volts to neutral, now I don't think it will ever trip a main if there happens to be a fault as a extension cord faulted and it just dimmed the lights almost out, till the worker yanked the cord out, but i gave them a price to install a new 200 amp single phase service and eliminate this tranny as it is going to cause a fire, but they never got back to me on it???

What amazes me is how small this little tranny is compared to a 10kva pot on a pole, while I know the windings in a utility tranny is much heavier then in these little tranny's just how much I have no idea.
 

hurk27

Senior Member
But back to the OP, since the loads of this house and the loads of other services dim the lights then it has to be at the transformer or ahead of it, there could be a bad primary connection somewhere ahead of the transformer that would cause this problem, even the loss of the MGN can do this because the transformer is trying to return its current through Earth which is not a good conductor (or should I say the connection to Earth) there is a voltage drop, and it is ahead of the service of this house, that is all you can do as it will be up to the utility to take it further.
 

speedypetey

Senior Member
Hi Swami, how are you?

My home is wired with ALL #12 for lighting and receptacle branch circuits, and the circuits are pretty well laid out.
I STILL get lighting dimming when the refer, A/C, pool pump, etc, kick on.

Even if there is an "issue" (not sure what this means) with the setup next door, what do you propose is done? The POCO and electrician have both looked at it.
 
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