Please help me with this one. I received a call to a house on a beach that had their TV and lights acting funny. They had called the cable TV Co because of a cable problem and they said that the system was damaged and replaced. A cable splitter was found with a cable burnt at the connecter. Assuming lightning strike. I start at the panel. I have 130v on A leg and 118 on B leg. 249 across both. A toaster was turned on at the counter and the TV screen on the other wall would deform in color and eventually turn off, and the kitchen recessed lights would dim also. There is absolutely no overload as expected but a voltage drop to 90v. The TV is on a separate branch circuit. Back to the panel I go. I turn off all the breakers except for one in the basement with two pull chains and a dehumidifier in the corner. As soon as the dehumidifier calls I would read a quick voltage drop ahead of the main breaker. This problem occurred when any motor or call for current was being received. Is this a brownout? Please help.
Brownout
- Thread starter zaptd
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voltage dropping out
voltage dropping out
well here it is. I get into the house and when I turn on the toaster, microwave or anything of the sort i get a brown our or a voltage drop on the feed to 90V. Now down to the panel I go. I have 130V on one leg and 118 on the other and 249 across the two(before the main) I then turn off all the circuit breakers at the panel except for one allowing light for me at the panel. This light circuit also controls a plug on the wall where a dehumidifier is plugged into. When this dehumid calls I meter an extreme voltage drop to 30V on the legs. The lights in the basement also go dim. This is what is happening throughout the house. Lights are dimming and then getting brighter, clocks are losing their time and simple appliances cannot be operated. A cable company was called in before I arrived and fixed the damaged cable signal. The also found a coax line burnt at the connecter. A lightning strike was concluded. Can anyone help me with this. I do not know where to start. Im thinking of calling the power company and having them check regulaters?
voltage dropping out
well here it is. I get into the house and when I turn on the toaster, microwave or anything of the sort i get a brown our or a voltage drop on the feed to 90V. Now down to the panel I go. I have 130V on one leg and 118 on the other and 249 across the two(before the main) I then turn off all the circuit breakers at the panel except for one allowing light for me at the panel. This light circuit also controls a plug on the wall where a dehumidifier is plugged into. When this dehumid calls I meter an extreme voltage drop to 30V on the legs. The lights in the basement also go dim. This is what is happening throughout the house. Lights are dimming and then getting brighter, clocks are losing their time and simple appliances cannot be operated. A cable company was called in before I arrived and fixed the damaged cable signal. The also found a coax line burnt at the connecter. A lightning strike was concluded. Can anyone help me with this. I do not know where to start. Im thinking of calling the power company and having them check regulaters?
ultramegabob
Senior Member
- Location
- Indiana
sounds like an issue with the neutral, are you getting these low voltages on the line side of the main to the line of the neutral buss coming into your paneL? if so you may have to have the poco open the meterbase and take readings there. it could be in between the meter and the main, or somewhere down the line before the meter.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
This is a text-book description of a high-resistance neutral issue. The coax is burning up trying to carry neutral current.
The problam can be anywhere from the utility transformer to the service panel. You might have to call the POCO in.
The problam can be anywhere from the utility transformer to the service panel. You might have to call the POCO in.
JohnJ0906
Senior Member
- Location
- Baltimore, MD
LarryFine said:
I agree, Open or loose neutral.
The figure of 249 volts across the two legs is a bit high, if the standard of 120/240 is the norm for your POCO. That is over 10% high.
In addition to investigating the neutral issue, have the POCO check the transformer serving your client. I'm willing to bet a case of your favorite beverage that it is damaged.
If the voltage drop is the same on both legs. or if BOTH legs drop under a load, then it may not be a neutral issue, as neutral troubles will usually drop one leg and raise the other. Did that happen in your testing? IE, with a load on did one leg drop and the other raise? If only one leg dropped and the other stayed the same, or if both legs dropped, then it's more likely a transformer issue.
And I'd ask the neighbors on either side of your client if they are having issues as well.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
yes. Read his post(s) again.mxslick said:
I'm soooo confused..
I'm soooo confused..
Larry, I did read them a few times to see if I was thinking in the same direction everyone else is, but this
is the statement the op made that has me thinking there is a transformer issue. That and the high leg-to-leg voltage.
We'll have to wait and see what the OP finds to be sure though.....
I'm soooo confused..
Larry, I did read them a few times to see if I was thinking in the same direction everyone else is, but this
is the statement the op made that has me thinking there is a transformer issue. That and the high leg-to-leg voltage.
We'll have to wait and see what the OP finds to be sure though.....
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
The coax shield is bonded to the utility neutral on the poles, and in the premises. They're basically paralleled. The service neutral is supposed to have a lower impedance than any other pathway, due to sheer size.fireryan said:
Remember, a neutral keeps its load end as close as possible to the same potential as the source end by carrying current. If you interfere with that ability, a voltage difference developes.
Now, imagine the service neutral developes a high resistance. It will shed a portion of its current to parallel conductors, such as the coax shield, metallic water supply systems, etc.
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