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.
Thanks,
Dave.
P.S.- I am a long time reader but this is my first post. Great forum!

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

http://www.universalballast.com/

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

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.

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.
Dave

Hi Dave,
Welcome along, mate.

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).

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.

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

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.
Dave

NHSparky:
Welcome to ECN, from one of the 'Jersey Guys'

Thanks all for the welcome. Hopefully I will be able to add my 2 cents worth in the future.
Dave

Nhsparky, you have described a problem that a customer called me with to a tee. I talked with a resident electronics guru and he basically told me there was nothing that could be done, but he did not know about the different ballast type, I will see what these things cost and suggest them to my customer. Thanks for the info.

The type of balast does not only impact on electronics.

I know somebody with special needs kids (austic) and the school they attend had to change out the fixtures in the new additon that opened last September as the noise / EMI was affecing the whole class.

The teachers, GC site superintendent, and electrical contractor were the only ones who could not hear or feel what ever the ballast was putting out. The fixtures were swapped over a weekend and the classes behaviour change was noticable on Monday morning in the new wing.

I find it hard to accept that this is due any electro-magnetic field effect.
It is accepted that youngsters are susceptible to high frequency audio noise which is inaudible to older humans. Perhaps that is the cause here?

One solution to the RFI. Go to an electronic supplier and get some ferrite beads (choke) and put several on each lead leaving the ballast. I had this problem and they completely eliminated the RF noise. I keep a supply on the truck. Lots of switching power supplies create RFI. Ever wonder why lots of electronics has that lump on the power cord. Thats a ferrite choke to stop HF RFI from going out the cord. They are cheap and come in both tube style and split to allow installation on a connected wire.

New ballasts arrived today. I plan on installing them next week. I think I will bring my job radio in with me for a before and after test. The only problem is, on this job I am changing out old magnetic ballasts and T12 lamps for Electronic ballasts (residential grade) and T8 lamps. If all goes well there shouldn't be any RFI. We'll see!
Stay tuned
Dave

Well, the jury is in. We installed 9 ballasts today on one job, checking for RFI before and after.This job was replacing old magnetic ballasts and T12 lamps for electronic ballasts (residential grade) and T8 Lamps. No RFI noted before or after.
Second job of the day, replace two commercial grade electronic ballast with two new residential grade ballasts. RFI before the change was unbearable on the radio. RFI was nonexistent after the change.
So i guess the rule of the day is ,if your going to install flourescent fixtures in a residence, make sure you specify residential grade ballasts in your fixtures.
Dave