Hum in Sodium Light Ballast - a problem?

[bmwjohn]

Hi:
I'm not sure where to put this, but BITOG readers seem quite up to date on many topics. I have replaced my porch light with a 70w sodium side light unit - looks like old porch light. It is almost too bright but security is my main concern and this was cheap to buy and run and install and covers a 40' deep front yard. However, I get a loud hum from the ballast from when it starts at night to early morning shut off. My concern: could this lead to an electrical fire, etc? The noise I can stand, the flames I can't.Thanks!

 

[toyotapriusguy]

I only have experience with ballasts for Metal halides but they've always had a hum, from brand new to years old.

Where I grew up they used high pressure sodium lights in the street lights and they hummed loud and hard

 

[spackard]

I guess I'd try to exchange it.
The noise is the plates in the magnetic ballast. If they're not really tight they "rattle" at 60Hz. I've seen ones where they run a weld along all the laminated iron plates to hold them together. Probably a decade ago I bought a 70w sodium with a daylight sensor on it and it was very quiet.

 

[Rob_Roy]

I have two HPS outside lights, they both hum...the oldest one is louder. Without hearing yours it is tough to say if it is normal or not. If you are worried about it, swap it out.

 

[Samilcar]

I mainly deal with 1000W and 1500W metal halide and HPS ballasts for my work, and have found that some ballasts are simply noisier than others. The very noisiest ones we return for credit, as we've found customer complaints regarding the noise is almost guaranteed. This is not a fire hazard, just a noise issue. Defective lamp capacitors can catch on fire, but not ballasts. If a ballast fails, it simply goes dead.

 

[bmwjohn]

Well, no more light fixture hum, no more light, just a glow. I'm guessing ballast is dead?

 

[Samilcar]

Hard to tell. It could just be the bulb itself. If the lamp itself won't strike, then the noisy ballast won't hum.