Noise on circuit wiring

[Fred B]

I've got a large residential building, very old house, some old rag wire no grounds, that is creating so much RF interference that circuit tracer can't even be heard. I've had this on occasion that was usually related to just a couple of circuits, but this one I've got so much interference that it is on every panel (home has 4 panels) and a couple of rooms can actually pick it up in the middle of the room. Now question is what would be the source? POCO? Some sort of equipment? How would I track it down, or can anything actually be done? Is it dangerous to equipment or wiring? This house is getting a change that may initiate the installation of AFCI on some of the circuits, will this level of RF be an issue with them?

 

[synchro]

I've got a large residential building, very old house, some old rag wire no grounds, that is creating so much RF interference that circuit tracer can't even be heard. I've had this on occasion that was usually related to just a couple of circuits, but this one I've got so much interference that it is on every panel (home has 4 panels) and a couple of rooms can actually pick it up in the middle of the room. Now question is what would be the source? POCO? Some sort of equipment? How would I track it down, or can anything actually be done? Is it dangerous to equipment or wiring? This house is getting a change that may initiate the installation of AFCI on some of the circuits, will this level of RF be an issue with them?

You could try turning off breakers and check if the interference changes or goes away.

You might also take a portable AM radio, tune it between channels, and listen to check whether you hear interference. Move outdoors and see if it changes. The nature of the audible noise, if present, (i.e., clicking, buzzing, tones, etc. may provide some clues). Move the radio around and see if you can localize the noise to one place. Go by the meter to see if it's present there.

Does the house have any knob and tube wiring? That might radiate any noise present on the conductors more efficiently because of the greater separation between circuit conductors.

 

[ptonsparky]

K&T plus neutrals and hots grabbed from wherever.
Do the radio trick as suggested. Turn it all off first, then one at a time.
Old homes with multiple panels scream neutral bond issues.

 

[K8MHZ]

I've got a large residential building, very old house, some old rag wire no grounds, that is creating so much RF interference that circuit tracer can't even be heard. I've had this on occasion that was usually related to just a couple of circuits, but this one I've got so much interference that it is on every panel (home has 4 panels) and a couple of rooms can actually pick it up in the middle of the room. Now question is what would be the source? POCO? Some sort of equipment? How would I track it down, or can anything actually be done? Is it dangerous to equipment or wiring? This house is getting a change that may initiate the installation of AFCI on some of the circuits, will this level of RF be an issue with them?

What are you 'picking it up' with?

 

[Speedskater]

If it's a pulse type noise check:
a] doorbell transformer
b] burnt-out CFL bulbs that are thought to be switched off.

 

[Fred B]

What are you 'picking it up' with?

Both the circuit tracer, my fox and hound, and even my 2way radio will get a buzzing static noise as I walk through different rooms. The tracers will get same buzzing static as I get near the wires or breakers on about 30 of 40 breakers. Even with sending unit off the receiver gets the static.

 

[milldrone]

Even with sending unit off the receiver gets the static.

A switch mode power supply can cause this type of noise. This can include wall warts, computer power supplies, big screen tv''s any thing electronic.

 

[K8MHZ]

Both the circuit tracer, my fox and hound, and even my 2way radio will get a buzzing static noise as I walk through different rooms. The tracers will get same buzzing static as I get near the wires or breakers on about 30 of 40 breakers. Even with sending unit off the receiver gets the static.

Have you been able to identify which breaker is powering the static producing device? That's kind of step one for me, and I have a bit of experience tracking down noise on electrical systems from my radio background.

 

[K8MHZ]

A switch mode power supply can cause this type of noise. This can include wall warts, computer power supplies, big screen tv''s any thing electronic.

Plasma TV's are a ham radio operator's worst nightmare. They splatter interference all over the place, even from the house next door.