Mike Dolt Enterprises
Mike Dolt Enterprises
User: B W E, Location: Michigan. It's a beautiful peninsula, I've looked
Asked on: Saturday, April 30, 2011 at 11:49 am EDT
Answered on: Tuesday, May 14, 2024 at 4:49 am EDT
Question: Hey guys, this one has me stumped. A guy calls because his paper shredder, blow dryer, and electric massager all cause interference (visible static) on his TV and (audible static) on his radio.They cause static when plugged into different (but not ALL) receptacles. The paper shredder causes interference on the TV when plugged into the kitchen Island outlet, but not the disposal outlet. It does it when plugged into it's normal wall receptacle (a newer, all copper addition), as well as when plugged into a surge suppressor.There is no correlation between the shredder outlet and the tv outlet, nor between any of the other devices (different circuits, different phases, etc.) The original house is aluminum, and was pigtailed, but upon inspection yesterday, the guy used red wire nuts, but no Noalox. All copper/aluminum connections are dry.The cable service coming in to the house is grounded, but it goes from the ground block where the cables are coupled together to a little clamp on a piece of 1/2 emt with the paint scraped off. The emt runs through two bell boxes before it gets to the panel.The neutral/ground bar of the main panel has a #4 neutral (going to a sub panel) as well as the #6 solid landed on the same lug. There is no other place for it to go.There is a driven rod at the main panel with the #6 passing through the ground clamp and going on to the cold water.The sub panel does not have a separate ground bar, or a ground wire. There is one ground wire coming in to the panel from the house that is landed on the neutral bar. The circuit that the shredder plugs into is fed by the sub panel (Copper). The TV and clock radio that are receiving the interference are on the main panel Aluminum).I thinks thats about all I can tell you. If you have any advice I'd love to hear it.
Possible Causes
Bad Electrical Connections
The use of red wire nuts without Noalox on aluminum wiring can lead to high-resistance connections, causing arcing and interference.
Improper Grounding
The grounding system described (EMT with clamp painted over) is not an effective grounding path.
Neutral-Ground Bond
The neutral-ground bond at the main panel may be improperly bonded, causing current to flow on the neutral and create interference.
Multiple Ground Paths
The sub panel has only one ground wire coming in from the house, which may not provide adequate grounding for all circuits.
Faulty Surge Suppressor
The surge suppressor may not be functioning properly and could be introducing interference.
Recommended Troubleshooting Steps
1.
Verify Electrical Connections
Ensure that all electrical connections are tight and secure, especially those involving aluminum wiring. Use Noalox or other anti-oxidant paste on aluminum connections.2.
Inspect Grounding System
Replace the EMT with a properly grounded wire and ensure that all grounding connections are clean and tight.3.
Check Neutral-Ground Bond
Verify that the neutral-ground bond at the main panel is properly installed. The bond should be located on the main neutral bus.4.
Add Ground Wire to Sub Panel
Install a separate ground wire from the main panel to the sub panel to provide an adequate grounding path.5.
Replace Surge Suppressor
If the previous steps do not resolve the issue, try replacing the surge suppressor with a new one.6.
Contact Cable Company
If the issue only occurs when using cable TV, contact the cable company to troubleshoot the grounding of their system.
Additional Considerations: The paper shredder may have a built-in fan that can generate static electricity. The blow dryer and electric massager may have electrostatic discharge issues. The location of the affected outlets may be relevant, especially if they are near other electrical devices or wiring. Flag for review