RadioReference on Facebook   RadioReference on Twitter   RadioReference Blog
 

Go Back   The RadioReference.com Forums > Amateur Radio > Amateur Radio General Discussion

Amateur Radio General Discussion General discussion forum for amateur radio topics not covered by the above forums.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 01-31-2013, 5:47 PM
Member
  Amateur Radio Operator
Amateur Radio
 
Join Date: Oct 2012
Location: Colorado Springs, CO.
Posts: 8
Default Noise on power lines

I have some very bad noise in my shack. The worst is light dimmers in the house.. The shack is fed by four wires to a building about 140 feet away from the house. I put in a sub panel to feed the circuits. The panel box is grounded to the main box in the house, and the neutral is also tied to ground at the house. The new panel box also has ground rods at its site. For noise where should I put some bypass caps, from the legs to neutral or to ground? Should there also be a cap from neutral to ground? For lighting protection it sounds like everything should be grounded to a common point, but can I tie the ground and neutral together? I have read a lot of articles, however I have not come up with suggestions when using the four wires.
Reply With Quote
Sponsored links
  #2 (permalink)  
Old 01-31-2013, 8:02 PM
popnokick's Avatar
Member
  Premium Subscriber
Premium Subscriber
 
Join Date: Mar 2004
Location: PA
Posts: 809
Default

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 6_1 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B144 Safari/8536.25)

Self-installing caps on supply mains? Tieing ground and neutral together? Strikes me as not quite good practice, but don't take it from me. And your homeowner's insurance might be kinda slow to pay a claim if anything happens. Tell your power company you have a radio interference problem coming from their equipment, and follow their advice. Or a licensed electrician who understands RF noise suppression.

Last edited by popnokick; 01-31-2013 at 8:08 PM..
Reply With Quote
  #3 (permalink)  
Old 01-31-2013, 9:12 PM
Member
  Premium Subscriber
Premium Subscriber
 
Join Date: May 2002
Posts: 2,172
Default

The only place the neutral should be connected to ground is where the overcurrent protection or metering is located. That is the only place the interconnection between the neutral and grounds whether it be a water pipe or ground rod or both. (Codes require both now)
You should never tie them together at any other place, especially at a sub panel or another building. The ground wire going to your building should not be connected to any neutral conductor but only be used as an equipment ground at he building; and needs to be sized properly. Some of these things being not right could possibly cause noise problems but I doubt it.
Reply With Quote
  #4 (permalink)  
Old 02-01-2013, 5:07 AM
Member
  Amateur Radio Operator
Amateur Radio
 
Join Date: Jul 2009
Location: Minneapolis, MN
Posts: 82
Default

I agree that the neutral and ground should never be bonded together at all. As for the ground rod at the sub panel that does sound OK from what I remember with NEC for that distance. If you've got them bonded and have any tranient voltage from the neutral to ground, that could be causing a large part of your noise problem.

It would not hurt to have an electrician come out and inspect the entire electrical setup to see if they can find any additional problems.
Reply With Quote
  #5 (permalink)  
Old 02-01-2013, 11:02 AM
W9BU's Avatar
Lead Wiki Manager
  RadioReference Database Admininstrator
Database Admin
Amateur Radio Operator
Amateur Radio
 
Join Date: Jul 2004
Location: Brownsburg, Indiana
Posts: 2,869
Default

Quote:
Originally Posted by N0YFE View Post
I agree that the neutral and ground should never be bonded together at all....It would not hurt to have an electrician come out and inspect the entire electrical setup to see if they can find any additional problems.
Any residential electrician will tell you that the National Electric Code requires that the neutral and ground be tied together at the main breaker panel.
__________________
Lead Wiki Manager and Moderator for the Radio Reference Amateur Radio Forums.

"The whole world's living in a digital dream. It's not really there, it's all on the screen." -- Joe Walsh WB6ACU
Reply With Quote
Sponsored links
  #6 (permalink)  
Old 02-01-2013, 1:34 PM
Member
  Amateur Radio Operator
Amateur Radio
 
Join Date: Jul 2009
Location: Minneapolis, MN
Posts: 82
Default

Quote:
Originally Posted by W9RXR View Post
Any residential electrician will tell you that the National Electric Code requires that the neutral and ground be tied together at the main breaker panel.
Thanks for the information. I see my mistake now.
Reply With Quote
  #7 (permalink)  
Old 02-01-2013, 4:50 PM
Member
  Shack Photos
Shack photos
Amateur Radio Operator
Amateur Radio
 
Join Date: Jun 2006
Location: Bellevue, WA
Posts: 2,167
Cool

Quote:
Originally Posted by KE7XD View Post
I have some very bad noise in my shack. The worst is light dimmers in the house.. The shack is fed by four wires to a building about 140 feet away from the house. I put in a sub panel to feed the circuits. The panel box is grounded to the main box in the house, and the neutral is also tied to ground at the house. The new panel box also has ground rods at its site. For noise where should I put some bypass caps, from the legs to neutral or to ground? Should there also be a cap from neutral to ground? For lighting protection it sounds like everything should be grounded to a common point, but can I tie the ground and neutral together? I have read a lot of articles, however I have not come up with suggestions when using the four wires.
Buy some better switches. Most of the newer switches have RFI filters built in.

e.g.

Shop Lutron Maestro 5-Amp White/Gloss Digital Dimmer at Lowes.com

Also, you might want to invest in some Corcom filters. Depending on how much amperage you use there are several relatively low-cost solutions to help cut down on noise getting into the shack from house mains.

General Purpose RFI Filters

(Used models can be found on EBay and/or you can buy them from electronic supply places like mouser, etc.)

The Corcom filters work great.

Unfortunately, filters won't help you if you have this: http://www.youtube.com/watch?v=8SgW9JjIUac

Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 1:04 PM.


Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
All information here is Copyright 2012 by RadioReference.com LLC and Lindsay C. Blanton III.Ad Management by RedTyger
Copyright 2011 by RadioReference.com LLC Privacy Policy  |  Terms and Conditions