faint buzz from SA US22-40 UPB switches when off

[js19707]

i replaced the switches in my hall bathroom which control the built-in light, nightlight, fan, and heater of my exhaust fan with a pair of SA US22-40 (dual dimmer w/ changeable faceplate) UPB switches, each with a double switch faceplate. i configured the switches to disable dimming (i assume fan and heater are inductive loads), and i'm using the switches built-in timer functionality to ensure the fan and heater get turned off automatically after N minutes.

now that i've got everything wired up, it all seems to work fine, but i've noticed that both of these switches emit a faint buzzing noise all the time. This is different from the typical (and louder) UPB switch buzz that comes from transmitting links.

i have ~30 UPB switches installed in my house, mostly HAI and PCS brand. none of those switches emit any noise when the switches are off, and when they do buzz it's always associated with a UPB transmission. these are the only two SA switches I have installed in my house so i'm not sure if this is 'typical' but searching here and elsewhere doesn't suggest that it is.

has anyone experienced this symptom? is this a sign of a problem with the switches, or my wiring of them, or is this normal?

 

[js19707]

so, i just took a walking tour of my other UPB switches, and it seems the HAI and PCS switches do emit a very faint buzzing noise all the time too.. but i had to put my ear right up against these switches to hear it and even then it was pretty faint.

the buzzing from the new SA switches is audible 4-5 feet away. the UPB transmission noise is even louder.

any advice on whether this is typical of these switches would be appreciated, and whether there's anything which can be done to mitigate it. my main concern is safety--i want to make sure this isn't a sign of some other problem. however i'd also like to be prepared if/when my wife notices the buzzing

 

[tenholde]

so, i just took a walking tour of my other UPB switches, and it seems the HAI and PCS switches do emit a very faint buzzing noise all the time too.. but i had to put my ear right up against these switches to hear it and even then it was pretty faint.

the buzzing from the new SA switches is audible 4-5 feet away. the UPB transmission noise is even louder.

any advice on whether this is typical of these switches would be appreciated, and whether there's anything which can be done to mitigate it. my main concern is safety--i want to make sure this isn't a sign of some other problem. however i'd also like to be prepared if/when my wife notices the buzzing

I've never noticed my SA switches buzzing, except when transmitting. Have you checked to make sure that your switches are rated to support the load of a heater?

tenholde

 

[Desert_AIP]

I have over 30 SA switches. Mine only buzz when transmitting.
Sounds like something on the line is generating noise.
Especially since you hear buzzing elsewhere.

I'd disconnect the SA switches and go to the other switches to see if you can still hear the faint buzzing, if you can it's something on the line not related to the new SA switches.

If it is the SA switches it might be they are not fully turning off or the heater is too noisy for them.

 

[js19707]

looking at the datasheet for my bathroom fan/heater, i see:

Electrical Rating: 120 volts, 1717 watts
Heating element: 1500 watts

so..

1717W/120V = 14.31A
1500W/120V = 12.5A

because all 4 channels feed into the fan (2 for lights, 2 for the fan and heater), i'm not sure how the power load is distributed, but looking at the datasheet for the fan, it says "WIRING 115-120 volts (20 amp circuit only), 12 gauge wire"

so.. i think you may be on to something. it seems like i need something rated for 20A for the exhaust fan and heater?

 

[tmbrown97]

With loads that high, I'd look at expanding to separate switches (bigger electrical box - this isn't too hard actually) and 15amp relay switches... the 2240 has two 550Watt loads, which means about 4.5 amps each. You're severely overloading that thing and at risk of a serious meltdown or fire - you shouldn't even turn that thing on ever again.

Here's what you should be using for loads like that:
http://www.automated...hes/HAI-40A00-1

I have over 40 SA switches in my place - and I've never hear anything from them except when they're communicating... no full-time buzzing... so I don't know if it's from being overloaded or other conditions in your place... but it's probably irrelevant since that switch *can't* stay there (unless you're hoping for an insurance fire - in which case, turn on both loads and go out for breakfast).

 

[Desert_AIP]

Wow!

Definitely exceeding the switch capacity.

UPB switch issue aside, anything else on that circuit!?
What wattage are the lights?

 

[js19707]

UPB switch issue aside, anything else on that circuit!?
What wattage are the lights?

All of the bathroom is on a single 20A breaker; besides the exhaust fan (w/ built in heater and lighting), there's 4 sets of outlets and 4 lighting fixtures: 2 are 4x40W incandescent, 1 is 75W incandescent, and 1 florescent canned light.

thanks everyone for all your timely and helpful replies! i should probably explain what's going on in a bit more detail: our bathroom exhaust fan / heater works well but we want it on a timer so we can let it run without worrying about it being on all day when we leave the house. given the use of UPB elsewhere in our home, i thought this would be pretty simple but it's clear i underestimated its current draw. the existing electrical box is 3 gang: one rocker for the lighting fixture, and 2 sets of switches for the exhaust fan on/off, heater on/off, fan light on/off, and fan nightlight on/off.

i was aiming to keep this a small project (i have a new baby--our first--coming literally any day now, so time to work on home automation is very scarce) by finding switches to swap in place of what's there now--without having to worry about ripping out the box and putting in a bigger one, or having to go back into the attic to put in a some in-line fixture modules.

in the interest of expediency, i'm thinking about forgoing upb and using a couple of simple timer switches and capping off the lighting on the fan... unless somebody here has a better idea? :unsure:

Work2Play: the HAI switch you pointed at is a 15A relay switch.. is that good enough? having now seen the note in the exhaust fan install instructions ("20A circuit only") i was assuming i needed to look only at 20A products.

Desert_AIP: FWIW, regarding the buzzing, i still hear constant but very faint buzzing on all my UPB switches even when the bathroom circuit breaker is flipped off (so it shouldn't have anything to do with these SA switches i put in, right?). but i do have to put my ear within a few inches of these switches in a quiet room to hear it. other people don't have this?

 

[tmbrown97]

Your instructions call for a 20 amp circuit, but I think that's for the overall load of the fixture... the specs you linked under 15 amps for each switch load. You should be perfectly fine because there wouldn't be more than 15 amps passing through either switch.

The gang-box replacement really isn't that bad... 2 hours max. And I've installed over 40 UPB switches in the last 2 months since my 2nd child was born... you'll be fine

 

[Desert_AIP]

All of the bathroom is on a single 20A breaker; besides the exhaust fan (w/ built in heater and lighting), there's 4 sets of outlets and 4 lighting fixtures: 2 are 4x40W incandescent, 1 is 75W incandescent, and 1 florescent canned light.

I know this isn't a "Home Automation" topic, nor the direction you probably wanted the thread to go, and I'm no electrician, but you've piqued my curiosity so I have to ask.

How old is your house?
Are you sure the outlets are on the same circuit as the lights and everything else?
Do you have GFCI breakers or outlets?
Is your house new enough to require Arc fault breakers?
IIRC the outlets and lights need to be on separate circuits (again I'm not licensed and I'm too lazy to go look it up ) .


Adding all the loads you listed on that single circuit (assuming 35W for the flourescent and nothing plugged in) I get 2147W or 17.9A.
Again, IIRC, you need to have some overhead, something like 80% of the specified current limit, which would be 16A continuous loading of a 20A circuit.
If you turn everything on and then plug in a hairdryer and turn it on do you trip the breaker?

Not trying to confuse the issue or scare you, but something doesn't sound right.

 

[tmbrown97]

Desert_AIP - my house is only 5 years old - and they have outlets and lights on the same circuits... GFCI's are in all the bathroom, kitchen, and exterior outlets. Arc Faults are on the bedroom outlets. The breaker's should never be rated for more than the wire;

I'm a little surprised the other lights would be on the same circuit with a load that high; but hopefully it's legal/legit.

 

[Desert_AIP]

I was just curious, I'm sure you're fine.
Unless for some strange reason someone added the heater after inspection.

As for the buzz, sounds like it isn't the SA switches, maybe with the overload you just heard it louder there.

If you turn every UPB controlled item off, do you still hear it?

If no, then I would go one by one turning things on until you heard it.

 

[js19707]

thanks everyone. i ended up running to Lowes and grabbing a couple of 20A 60-min analog timers, capping off the fan light and nightlight, and putting in a HAI UPB dimmer on the incandescent light fixture. it all works fine AFAICT.

Work2Play: it sounds like i should get some tips from you, putting in a larger box sounds like more than 2 hrs work to me between cutting the drywall, removing the old box (when i've had to do this, i've used a dremel), and putting in a new one.

Desert_AIP: house was a down-to-the-studs remodel abt 7 years ago (i've owned it abt 3), including the electrical system. pretty sure the outlets and light fixtures are on the same circuit here in the bathroom and in other rooms. there is a GFCI built into the breaker for this and other circuits. i'm not sure if there are AFCI breakers, i'll take a closer look next time.

as for the buzzing, all the UPB switches in my house seem to emit a very faint buzz that can only be heard if i put my ear within an inch or two of the switch--this buzzing is always there, regardless of whether that unit or any other is on or off, but i have to strain to hear it. this is much softer than those SA switches were when they were installed. if/when i have some spare time i'll try installing one of these switches elsewhere and listen to see if the buzzing from them is any less when attached to a reasonable load.

 

[dBeau]

I have about 60 SA switches in total. Almost all are US2-40's and none make the buzzing noise you describe. However, I do have two US22-40's and both buzz even when there is no load. I cant help but to agree with the other posters regarding your use of the switches, but I really dont think that's why they are buzzing.

 

[AutomatedOutlet]

You might also think about installing a 20amp inline relay module for that heater/fan.