Low Voltage MR16 Hum Part 2
Hey thanks for the help everyone. I discovered something last night that may be of interest with this hum. To recap, I have seven zones (each on its own dimmer switch) of brand spankin’ new low voltage mr16 lighting, three of witch hum under full output. I have now found, in each case, it’s coming…
Hey thanks for the help everyone. I discovered something last night that may be of interest with this hum. To recap, I have seven zones (each on its own dimmer switch) of brand spankin’ new low voltage mr16 lighting, three of witch hum under full output.
I have now found, in each case, it’s coming from one fixture (out of 5 fixtures). Removing the bulb from the buzzy fixture reveals that the hum is coming from above the recessed can. Plugging the bulb in changes the pitch of the hum slightly (and makes the bulb hum a bit too). All the bulbs throughout the entire house are the same exact type: 50w 120v mr16, which is what the stickers inside the cans say is the max bulb.
I am not an electrician and have a healthy respect for something that can kill me, so I don’t want to poke further. Is this something my electrician should be doing? He said originally it was line noise and that it’s unavoidable. I think he has done something wrong, or a brand new part is not operating correctly and he just doesn’t want to deal with it.
Any thoughts as to what I should do next?
Thanks everyone! I will try the bulbs (As I happen to have some 35w ones around). If no dice, I’ll hound the electrician for a new transformer.
Could someone recommend a great, and I mean Mike Holmes/Bob Villa great, electrician?
Hire a licensed electrican. Most likly the transformer is bad.
“overload”
It’s now obviously the transformer.
If one bulb unplugged reduces the hum you may be have an overlt (another clue is that all transformers are humming, unlikely that all are bad).
Try replacing 1-3 bulbs with 35w and see if it stops. The socket may accept 50w bulbs, but the transformer may not be rated for 50 x (number of bulbs per zone).
Thank you both, sorry the 120v was a mistake, they are indeed 12v.
I am getting one fixture only, buzzing, even on full output.
The cans unfortunately do not have a model name. Think I’ll call my contractor.
Thanks again.
If the rating is for 120V then those recessed fixtures are line voltage, meaning the bulbs are illuminating directly from the 120V power feeding them.
Otherwise the sticker would call for 12V bulbs, meaning the 120V line power is being transformed to the lower-voltage.
The MR16s used for line voltage fixtures are further delineated as GU10s, which refers to the prongs that are inserted into the fixture. In order to ensure 12V and 120V bulbs don’t get placed into the wrong fixtures, the prongs are different.
My electricians prefer line voltage fixtures when the fixture count on a switch is low and low voltage for when it is high.
You should be very wary about DIY troubleshooting. If you figure out the make and model, the manufacturer should be able to give you guidance.
There’s more info here:
http://www.besthomesystems.com/learn/lighting_step7.html
You probably are in need of an electrician. But, first, a few points:
(1) “All the bulbs throughout the entire house are the same exact type: 50w 120v mr16.” Might be the most obvious problem here, though I doubt it. MR16 bulbs usually have different mounts for 12 volt and 120 volt, so you can’t use the wrong bulb. But, you say you have a low voltage (i.e., 12 volt) system, but above you say you are using 120 volt lamps. Please check.
(2) If it is a low voltage system, there is a transformer to knock the current down from 120 to 12 volts. All transformers hum to some extent, some more than others. I suspect that the transformer for each of your zones is above the light that you say is humming. But, the humming (which is usually not very load at all) may be aggravated by (a) cheap transformer, (b) poor installation (e.g., instaling on metal studs without isolation), and/or (c) transformer type (magnetic are lounder than electronic). Some types of transformers can be quieted with a “debuzzing coil.”
(3) Low voltage transformers typically buzz more when dimmed, and halogen lights generally should not be dimmed 100% of the time.
(4) With limited exceptions, low voltage lights need special low voltage dimmers (which, of course, are twice the price). Use of the wrong dimmer will increase buzzing and reduce the life of your transformer.
N.B. I am not an electrician.