# Recommendation for Residential Power Line EMI/RFI/Signal filter

#### Meh-Lit Kim

Joined Apr 14, 2015
4
Hi,

At my residence (Northen Cali), I suspect that signals from powerline communications that the utility or electric vehicle charging stations are using are getting into my residential wiring.

Is there any kind of Residential Power Line EMI/RFI/Signal filter that I can install near my breaker box to block powerline communication signals (most likely 9 KHz - 500 KHz signals) and other transients from entering my residential wiring?

Thanks.

#### GopherT

Joined Nov 23, 2012
8,012
These frequencies may be those wonderfully efficient CFL and LED light bulbs inside your house.

How are you sensing the interference and what problems is it causing?

#### wmodavis

Joined Oct 23, 2010
739
Do you suspect that any of that suspected intrusive EMI/RFI is suspiciously causing a suspected problem? Or is this just an anti-intruder crusade?

#### #12

Joined Nov 30, 2010
18,167
You never know with these California types.
My old Verizon dsl line used inductors to keep the internet traffic out of the telephone part, but you can't easily do that with a mains power feed. It might even be unlawful. That leaves capacitors trying to work with the natural inductance of the wires. Still, the answer is always a matter of degrees. You might attenuate the higher frequency signal by 20db, 40db, or 60db, but it's almost impossible to kill all of it. This brings us back to wmodavis in post #3. Why do you think you have these signals and what harm are they doing? That will suggest a goal for the filters to achieve.

#### wmodavis

Joined Oct 23, 2010
739
"Still, the answer is always a matter of degrees" and $$. More dollars can contribute to more attenuation of suspected intruders. Define how much of that you have to contribute to the suspected solution. And I strongly suspect Gopher has suspected a suspicious simultaneous source with similar .... Oh Well you get the idea. Thread Starter #### Meh-Lit Kim Joined Apr 14, 2015 4 These frequencies may be those wonderfully efficient CFL and LED light bulbs inside your house. How are you sensing the interference and what problems is it causing? I've reverted using tungsten/incandescent light bulbs just to rule that out. One of my nearby neighbors got an electric vehicle (EV) some months ago along with a charger (I believe a level-2 charger). That's when I began hearing electrical humming inside my house, which I believe is from the wires. It's practically driving me bonkers. And more people are getting EVs nowadays. Also, my understanding of EV charging is that besides the vehicle drawing power from the utility, the vehicle would also need to communicate with the utility to arrange some sort of power consumption schedule, and there is some kind of narrowband powerline communications employed for this (could this be G3-PLC?) So, any suggestion for a filter to block anything in the range of 9 KHz - 500 KHz would much appreciated! #### Papabravo Joined Feb 24, 2006 12,767 Fact is you don't really know what is going on. Would you be up for renting a spectrum analyzer and doing some sniffing? Turns out that power lines and house wiring are really really crappy RF transmission lines. You might want to rethink your approach while you try to determine what is going on. Thread Starter #### Meh-Lit Kim Joined Apr 14, 2015 4 "Still, the answer is always a matter of degrees" and$$\$. More dollars can contribute to more attenuation of suspected intruders. Define how much of that you have to contribute to the suspected solution. And I strongly suspect Gopher has suspected a suspicious simultaneous source with similar .... Oh Well you get the idea.
Hi wmodavis,

As I mentioned above, I did not hear the electrical humming until a nearby neighbor got an Electric Vehicle (EV) and charging station, and there are other neighbors further away that got EVs as well.

I am willing to spend a up to 3K to fix this. Is there some kind of filter (active or passive) that can filter out these frequencies?

Also, what is a good meter/detector to detect these frequencies (9 KHz - 500 KHz)? I have a milligauss meter which won't pickup these frequencies as they are probably in the low freq band and middle freq band and not ELF/VLF.

Thanks.

#### Meh-Lit Kim

Joined Apr 14, 2015
4
Fact is you don't really know what is going on. Would you be up for renting a spectrum analyzer and doing some sniffing?

Turns out that power lines and house wiring are really really crappy RF transmission lines. You might want to rethink your approach while you try to determine what is going on.
Hi Papabravo,

Any suggestions on where to rent a spectrum analyzer in Cali bay area?

Thanks.

#### GopherT

Joined Nov 23, 2012
8,012
Hi wmodavis,

As I mentioned above, I did not hear the electrical humming until a nearby neighbor got an Electric Vehicle (EV) and charging station, and there are other neighbors further away that got EVs as well.

I am willing to spend a up to 3K to fix this. Is there some kind of filter (active or passive) that can filter out these frequencies?

Also, what is a good meter/detector to detect these frequencies (9 KHz - 500 KHz)? I have a milligauss meter which won't pickup these frequencies as they are probably in the low freq band and middle freq band and not ELF/VLF.

Thanks.

Before you start spending your own money on this, have you called the power company to report the problem and your evidence? Do not give suggestions of the cause or how to solve the problem when you call them, just discuss the evidence and why your evidence is an issue for you. They may (likely do) have filters that they can install.

#### #12

Joined Nov 30, 2010
18,167
Excellent! Papabravo might be the best person on this site to look into this.
Meanwhile, You need to look for when the car gets plugged in compared to when you "hear electrical humming" inside the house. Nine KHz is within hearing range but it must be vibrating something because humans can't hear electricity directly.

Papa is talking about renting a spectrum analyzer and Gopher is talking about taking the electric company to task for providing good quality service. I'm with Gopher for the first move. It's free to ask the provider to examine their product.

#### Papabravo

Joined Feb 24, 2006
12,767
I'm sure Electro-Rent has offices in the Bay Area.
http://www.electrorent.com/

I should warn you it's not particularly inexpensive. Sometimes there is no substitute for the right equipment. Don't expect them to teach you how to use the instrument, they just warehouse the stuff. I'd exhaust my low cost and free options first.