dugdeep said:LQB said:You can minimize this particular threat by measuring this high frequency noise level and take steps to lower it. [The method mentioned in Shijing's post above is to simply shut the breaker in the panel box for the bedroom circuit you intend to use. This will work as long as there are no other active circuits running through the walls and floor/ceiling - and it will not stop ground loop current.] The best way is to use a GS meter (https://www.stetzerelectric.com/store/stetzerizer-microsurge-meter/ - see also the EMF Exposure thread) to directly measure the noise at any wall socket. Then use either GS filters (https://www.stetzerelectric.com/store/stetzerizer-filter/) or Greenwave filters (http://www.greenwavefilters.com/stetzerizer-gs-filters/?gclid=CKqLz4HKzLQCFcKPPAodiXwAng) to reduce the noise and verify by direct measurement. You can easily get an order of magnitude (I've seen nearly 2 orders) reduction in this noise. The nice thing about the GW filters is that they also filter the ground circuit (GS does not), and filter up to 500MHz (GS filters to about 200KHz). [By doing this you also reduce your exposure to electric/magnetic AC high frequency fields throughout the house - and if you move, you just unplug them and take them away.]
Well that's good news! I've had 2 stetzer GS filters plugged into outlets in my house for a few months now. I was going to ask if they would help to minimize potentially harmful effects from the grounding hardware. Given what you've said here, LQB, I think I may get a couple more filters for the apartment.
If you get a few more filters, you might be better off with the GW filters since they filter the ground circuit and do so up to 500MHz (their lab measurements that they passed on to me). I have some of their filters and they work marginally better than GS filters as measured with a GS meter. You may want to pick up a GS meter so you know what suppression you are getting - it will also guide you to optimum placement of the filters for max suppression. The goal is to get to 30 or under on the meter (at all sockets) - I think under 50 is fine. If you get the meter, you can also help out others that may have a concern. You can also use the meter infrequently to test the levels since they can change with time and loading.
I recommend that folks try to share the cost of the meter ($100 - I think), then do a group bulk buy of the filters to get lower prices. The nice thing about them is if you move, you just unplug and take them with you. Before moving into a new place, you can test for the noise with and without filters for acceptability.