Arresting Power Surges on Cable/Broadband.

[checkthisout]

There is a 115KV line that runs in front of my house. Cable TV/Internet phone are lowest on the pole.

We have large trees that blow down at least once a year during windstorms.

When this happens, the tree contacts the upper line and then the cable TV/internet line conducting power into it momentarily.

It's an ongoing issue and always will be. When I built my garage, I found 4 previous cables the previous owner had run due to damage caused by power surges, induction etc.

During the last storm, this same thing happened. This time it fried the messenger wire on the pole which has caused the cable to drop about 18 inches down the pole and also fried RG-12 that feeds my house right where it attaches to the drop.

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Nothing downstream got fried, the grounding point on the side of the garage was even ok.

It fried (literally blew up) the splitter on my neighbors house up the street but all his equipment was ok.

I am afraid I may not be so lucky next time. What's the best way to address this?

 

[Mongo68]

Ask your cable company for a lighting arrestor. There should also be a location before the cable comes in the house where the line is grounded...

 

[wyliesdiesels]

Lightning arrestor and make sure bonding is up to snuff on both ends. I would ask cable company to come out and check the bonding/grounding on the pole side.

Also, use point of use surge arrestors.

 

[PCustoms]

Thread reminded of a thought I had last week. When a high voltage line crosses over a normal line, what happens if the line were to drop down and contact the lower voltage line?

There are 3 crossings on my way to work where trees could easily cause this.

 

[wyliesdiesels]

Thread reminded of a thought I had last week. When a high voltage line crosses over a normal line, what happens if the line were to drop down and contact the lower voltage line?

There are 3 crossings on my way to work where trees could easily cause this.

Define normal line. By normal line do you mean a secondary line ie 120/240 or 480/277?

And bare?

 

[PCustoms]

Define normal line. By normal line do you mean a secondary line ie 120/240 or 480/277?

And bare?

Medium voltage lines running in residential neighborhoods that pass under high voltage transmission lines.

When a line suddenly becomes energized to 70kV, does the transformer see the spike and pass on a higher voltage to the house, or is there an immediate fireworks display?

 

[Xicaque]

Who owns those trees causing you all these headaches? If they are yours, cut them.


Sent from my iPhone using Tapatalk

 

[checkthisout]

Medium voltage lines running in residential neighborhoods that pass under high voltage transmission lines.

When a line suddenly becomes energized to 70kV, does the transformer see the spike and pass on a higher voltage to the house, or is there an immediate fireworks display?

In order to increase voltage output on the secondary side of a transformer, My theory would be that you would have to have two different phases from the high line contact two different phases on the lower line without shorting to each other in the process.

If one phase of the high line contacts the lower line and puts one phase on low line over voltage, then the only way for the current to get passed into the house through the transformer would be arcing between the coil sets in the transformer. The oil in the transformer contacts the case which is grounded which would shunt the current to ground.

I have seen fried stuff inside houses that are fed by pole-mount transformers where the high line (probably like 7500 volts) contacts the drop into the house post-transformer.

 

[checkthisout]

Who owns those trees causing you all these headaches? If they are yours, cut them.


Sent from my iPhone using Tapatalk

They are 140' + feet tall. This would mean clearing a few miles of property at least 140' back from the lines. the prevailing winds mean only one side would have to be cleared I guess but yeah...that just aint happening.

 

[Xicaque]

They are 140' + feet tall. This would mean clearing a few miles of property at least 140' back from the lines. the prevailing winds mean only one side would have to be cleared I guess but yeah...that just aint happening.

Damn son! where are you? in the forest?

 

[larry4406]

How about some DIY solutions with brand and part numbers?

 

[DC73]

Thread reminded of a thought I had last week. When a high voltage line crosses over a normal line, what happens if the line were to drop down and contact the lower voltage line?

Stuff blows up. If the power system is designed properly, upstream fuses blow and/or circuit breakers trip within a few cycles mitigating any damage to downstream equipment.

When a line suddenly becomes energized to 70kV, does the transformer see the spike and pass on a higher voltage to the house, or is there an immediate fireworks display?

The transformer will see the spike and the surge will try to continue through the secondary side of the transformer. IF fuses blow and/or breakers trip fast enough, damage is limited. However, damage caused by events like this tends to be cumulative.

Don't trust the power system to protect your equipment. Make sure your grounds are all proper and ask the power company to verify their grounds. Good quality surge protection devices are a must for sensitive electronic equipment.

DC

 

[cybrdyke]

Intermatic Smart Guard whole house protector with replaceable modules.

or whole home protector plus coax and phone line protector.