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Re: [RFI] RFI from Electrolux Front Loading Dryer

To: rfi@contesting.com
Subject: Re: [RFI] RFI from Electrolux Front Loading Dryer
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 16 Mar 2011 19:06:03 -0700
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On 3/16/2011 3:20 PM, Charles Lewis wrote:
> I contacted Electrolux.  Their response was that they had never heard of 
> thatproblem.  They only suggested I try grounding the cabinet.  That is not 
> practical.

Go back to square one and start over. FIRST, you are required BY LAW to 
bond to ground the conductive enclosure of anything connected to mains 
power. :PERIOD.  This ground connection must be the green wire that MUST 
be run with the power wiring, and connected to Equipment Ground in the 
power panel that feeds it, which in turn must be bonded to ground at the 
panel where power enters your building.  These are the fundamental 
requirements of building codes in all of North America, and in most of 
the developed world. These are very well thought out requirements, 
intended to protect against fire, electrical shock,  and lightning -- to 
do anything less is both unsafe and stupid.

Second, it is quite common for laundry appliances to be improperly 
wired, both internally and externally, in a manner that can CAUSE 
problems with hum, buzz, and RFI.  Electrical codes (which carry the 
force of law) require that a 240V appliance be connected ONLY to the two 
Phase (Hot) conductors, plus the bond between the chassis and the Green 
Wire.  If there is something in the appliance that also requires 120V to 
run (for example, a small motor), that 120V load MUST be connected 
between one of the Phase (Hot) wires and the Neutral. Many electricians 
cheat by connecting 120 volt loads in appliances between Phase and the 
Green Wire.  This is unsafe, illegal, AND likely to cause hum, buzz, and 
RFI.

The chassis of the power entrance panel must be bonded to one or more 
ground rods, and also to every other ground associated with your 
building (telephone, CATV, ham shack,  etc.).  The word "bond" in this 
context means a short, fat conductor connecting the required points.

SO -- the first thing you should do is study carefully what I've said 
here, then verify that your laundry appliances are properly installed. 
If they are not, call the electrician back and tell him to do it right.  
And you should not PAY him to fix his mistake.

Once you know that the installation is proper, you're ready to figure 
out if the manufacturer screwed up with RFI.

73, Jim Brown K9YC


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