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RFI from electronic ballasts #187927 07/14/09 01:23 PM
Joined: Apr 2008
Posts: 20
nhsparky Offline OP
Good day everyone. I now have 2 customers complaining about the static on their AM/FM radios caused by the electronic ballasts in the new 2 lamp fixtures I have installed. I believe the ballasts are Magnetek. I apologize if this an old topic but I couldn't find any reference in the search section. Has anyone experienced
this and is there any cure.
P.S.- I am a long time reader but this is my first post. Great forum!

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Re: RFI from electronic ballasts [Re: nhsparky] #187928 07/14/09 01:36 PM
Joined: Jan 2001
Posts: 1,044
Tom Offline
You might try the following site to see if there is any info posted about RFI. I think most manufacturers offer an RFI filter but that is probably to prevent RFI entering the wiring system. Since electronic ballasts operate at a high frequency, there might be direct transmission through the air to the radio.

Magnetek has sold its product line to Universal

Few things are harder to put up with than the annoyance of a good example.
Re: RFI from electronic ballasts [Re: Tom] #187930 07/14/09 02:25 PM
Joined: Jan 2005
Posts: 65
petey_c Offline
nhsparky, I agree with Tom. Were these new fixtures or did you just replace the ballasts? What kind of fixtures had been replaced? Is the RFI coming from one or both fixtures? At worst, you may have to replace some ballasts. pete

Re: RFI from electronic ballasts [Re: nhsparky] #187932 07/14/09 02:37 PM
Joined: Jul 2004
Posts: 783
LarryC Offline
1) Are the lighting fixtures solidly grounded?
2) Are the lighting fixtures suspended or mounted to structural metal?
3) Are the correct bulbs installed(T8 vs. T12)?
4) Are the radios on the same circuit as the lamp fixtures?
5) Are they listening to AM or FM?
6) Is the signal they are trying to receive strong or weak?

Questions 1,2,& 5 relate to radiated interference.
Question 3 is because I do not know what happens with mismatched bulbs and ballast.
Question 4 relates to conducted interference.
Question 6 is about the relative strength of the interference to the desire signal.

Re: RFI from electronic ballasts [Re: LarryC] #187939 07/14/09 07:04 PM
Joined: Apr 2008
Posts: 20
nhsparky Offline OP
These are new 4' 2lamp fixtures with electronic ballasts and new T-8 lamps.
All fixtures are wired with new wiring and all are properly grounded. One customers fixtures are solidly mounted to the bottom of the floor joists in the basement. Another customers fixtures are hung from jack chain. In one instance the radio is on the same circuit.The other instance the radio is on a different circuit. The RFI (static) is on both AM and FM and it is full range on the freq selector. I do have questions out to the fixture rep. I have to go back and disassemble the fixture for ballast info.
They say it isn't supposed to happen, but I now have 4 installations ( after talking with other customers) with RFI. It will be interesting to see what the ballast people have to say.

Re: RFI from electronic ballasts [Re: nhsparky] #187956 07/15/09 04:36 AM
Joined: Jul 2002
Posts: 8,397
Trumpy Offline
Hi Dave,
Welcome along, mate. cheers

This was always going to happen with HF ballasts in lighting gear, the actual frequency is about 20kHz, so it sounds like this might be a harmonic thing coming from the ballasts.

One other thing to be aware of, make sure that the interference is actually coming from the lights themselves.
Reason I say that is because the interference could be coming from something else, like a wireless router (mine totally knocks out the AM band here).

Re: RFI from electronic ballasts [Re: Trumpy] #187962 07/15/09 08:33 AM
Joined: Apr 2008
Posts: 20
nhsparky Offline OP
Thanks Mike,
Fortunately, it was real easy to determine the source of the interference. In all instances, simply turning the light switch off eliminates the static. Turn the light switch back on, the static returns. The RFI doesn't bother CDs or tapes and I dont have any problem with the old magnetic ballasts. I would think RFI would be a UL test requirement.

Re: RFI from electronic ballasts [Re: nhsparky] #187966 07/15/09 11:31 AM
Joined: Jul 2004
Posts: 783
LarryC Offline
I would think RFI would be a UL test requirement.

It is in SOME applications. If the fixture is tested for use in Industrial environments, I believe it doesn't matter if it interferes with residential equipment. Just like big welders, they are not typically used in residential environments, therefore it doesn't matter if they interfere with TV and radio.

Try to determine if the interference is coming as radiated or conducted interference. Plug the radio into an extension cord that is plugged into another circuit. If the interference is significantly reduced or removed, the interfernce is being conducted into the radio thru the power line. A good line filter on the radio should fix the problem.

Larry C

Re: RFI from electronic ballasts [Re: LarryC] #187971 07/15/09 04:29 PM
Joined: Apr 2008
Posts: 20
nhsparky Offline OP
Well, this is the response from Universal.
The RfI generated by the ballasts in my light fixtures is normal. If I want to eliminate it, I must strip out these brand new ballasts and install what they call a residential grade ballast P/N B232I120RES-A. These ballasts cost twice as much as the supplied ballasts cost. So it appears this will be my responsibility to fix, for not insuring my supplier is stocking fixtures with ballasts in them that don't cause RFI.
Expensive lesson I hope nobody else has to repeat.

Re: RFI from electronic ballasts [Re: nhsparky] #187976 07/15/09 09:58 PM
Joined: Apr 2002
Posts: 7,261
HotLine1 Offline
Welcome to ECN, from one of the 'Jersey Guys'

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