Hi guys!

My office is in an old building and I suspect the AC 127V line of probably all of the outlets in one room are connected to the same fuse, the same line..

I'm having this problem. Whenever I activate an electric hands-free sink (by activating a 127V solenoid valve), to wash my hands, something happens, maybe quickly the voltage drops, I'm not quite sure yet, but other devices connected to outlets nearby "sense" this.

So an LCD monitor blacks out for a second, another device "resets" itself, as it turns off and on quicky. A subwoofer makes a loud noise...

I already called an engineer and although it would be better to separate the circuits, using different paths to the fuse box, in this building it is a nightmare to be done..

So, in one lcd monitor I changed the 60hz frequency to 59hz and the on-off on the screen seems to be gone when the sink is activated.

So, I know that re-doing all the cabling inside the walls would be the best, but for now it's not doable...

Is there any kind of AC filter or something like this I could use so this solenoid doesn't interfere with other devices attached to outlets on the same line?

I've heard a nobreak could help..., but is there something simple I could use to atennuate this?

English is not my first language, so I'm sorry if I'm not clear in my explanations

Thanks a lit for reading!

 

Your English is fine and the explanation is clear .
How much current does the solenoid valve draw? A suitably-rated common-mode choke in its supply lines might help.

 

Your English is fine and the explanation is clear .
How much current does the solenoid valve draw? A suitably-rated common-mode choke in its supply lines might help.

I´ll measure it and get back to you later! !! Thanks! I don´t know exactly in portuguese what is a commom-mode choke. eheheh... but I´ll try to find out!

 

I suspect that the "hands free sink" also has an instant water heater to heat the cold water supply and that it the large current that this takes that is causing the problem. I suggest monitoring the supply voltage and noting how much it drops when the sink is activated. You could also separate the solenoid valve from the rest of the unit and testing if the solenoid valve by itself causes the problem. If it is the solenoid valve that causes the problem then I think the problem is more likely to be sparking on the relay contacts that supply power to it rather than the solenoid valve itself. If it is then you could try fitting a transient suppressor across the contacts

 

Do you have a data sheet on the sink? Never thought I would ask that one.

 

I suspect that the "hands free sink" also has an instant water heater to heat the cold water supply and that it the large current that this takes that is causing the problem. I suggest monitoring the supply voltage and noting how much it drops when the sink is activated. You could also separate the solenoid valve from the rest of the unit and testing if the solenoid valve by itself causes the problem. If it is the solenoid valve that causes the problem then I think the problem is more likely to be sparking on the relay contacts that supply power to it rather than the solenoid valve itself. If it is then you could try fitting a transient suppressor across the contacts

Hi! It´s simply a solenoid valve connected to the water pipe that allows or not water to flow when I press a pedal, connected as a switch to 127V. There´s no heating on my sink. There´s no relay either..

I attached a picture of this valve...

I couldn´t find yet how much current it draws... I´ll have to measure it...

Thanks a lot!

 

Something's not adding up being those types of solenoid valves only draw a few watts at best.

Turn that on should be no different than plugging in a digital alarm clock. Tiny power draw not a huge one that would ever cause any degree of voltage drop a typical home electrical circuit would be affected by.

Is it wired wrong and connected between the live line and ground rather than the live and common line so its sending power back through the ground circuit and by chance that electrical circuit of the house is not grounded so it has to jump the returning power back through one or more devices grounds to get back to the common line and complete the circuit?

 

Perhaps the valve solenoid has a shorted turn, which is causing it to draw high current, and thus the noted disruptions when it is activated.

 

Do you have a data sheet on the sink? Never thought I would ask that one.

Perhaps a request for a source for the sink!
Max.

 

The other cause of initial high current on an AC solenoid is if something prevents or slows the armature motion, high current flows until picked up compared to a DC version.
Max.

 

The other cause of initial high current on an AC solenoid is if something prevents or slows the armature motion, high current flows until picked up compared to a DC version.
Max.

Sort of but on those tiny solids they use such fine wire that they operate in more of a resistive current limiting mode than an inductive impedance current limiting mode. Even without out the valve slug moving or even in them they still only draw a few more watts of power at worst.

Certainly not enough to cause larger device so the same circuit to drop out from under voltage or pick up severe audio ground loop line noise as he is describing. Especially so if he has 127 VAC on a normal 120 VAC circuit.

To me all of this screams improper supply wiring issues where live AC power coming back from the solenoid is being fed into a largely floating ground on that electrical circuit.

 

Sort of but on those tiny solids they use such fine wire that they operate in more of a resistive current limiting mode than an inductive impedance current limiting mode. Even without out the valve slug moving or even in them they still only draw a few more watts of power at worst.

Certainly not enough to cause larger device so the same circuit to drop out from under voltage or pick up severe audio ground loop line noise as he is describing. Especially so if he has 127 VAC on a normal 120 VAC circuit.

To me all of this screams improper supply wiring issues where live AC power coming back from the solenoid is being fed into a largely floating ground on that electrical circuit.

Hi!

So... can you give me some things to check to verify it? And... if there's a floating ground... what should I do? Can I simply ground the neutral wire, if possible?

Sorry, My electrical knowledge is basic..

Thanks for all your replies...

 

No the neutral cannot be grounded anywhere but the service entrance.
Max.

 

No the neutral cannot be grounded anywhere but the service entrance.
Max.

You mean it could be grounded on the fuse box, where all the wires for all the rooms are distributed?

Thanks!

 

Hi!

So... can you give me some things to check to verify it? And... if there's a floating ground... what should I do? Can I simply ground the neutral wire, if possible?

Sorry, My electrical knowledge is basic..

Thanks for all your replies...

I would start bey looking at how the wiring for the sink is set up since that's where the problem originates from.

Being is an old building it depends how old it is and it may very well have modern three wire electrical circuits in rooms that have been remodeled overlaid onto original two wire feed systems bringing power to the rooms.
I've seen that trick done in old houses many times. The remodeled and updated electrical in a room has all the correct wiring set up the way its supposed to but the main feed line to the room was never redone so all the new wiring third wire for a dedicated ground is electrically floating and largely doing nothing except for any incidental weak ties to the the common line through what ever built in protection circuitry any device plugged into it may have.

That would explain the loud buzzing your speakers pick up being they would begetting a partially live power feedback from the sink solenoid onto their ground reference line.

 

You mean it could be grounded on the fuse box, where all the wires for all the rooms are distributed?

Thanks!

Yes. if things have been updated properly and you have all three line sockets in the rooms all the wiring in the main power box should also have three lines as well.

If not and it still has two wire (usually looks like weaved cloth on the wiring not plastic) then someone cheated and only updated the wiring in the rooms but not the feedlines to them.

 

Yes. if things have been updated properly and you have all three line sockets in the rooms all the wiring in the main power box should also have three lines as well.

If not and it still has two wire (usually looks like weaved cloth on the wiring not plastic) then someone cheated and only updated the wiring in the rooms but not the feedlines to them.

The wiring in my office was re-done 10 years ago...
There's only two wires for all connections in all of my rooms. (old office building)
Two wires only also on the few 220v lines i've got for air compressor and air conditioning.
I only hear the buzz in the subwoofer nowadays. I used to have another one (another 2.1 sound system) that worked normally before...
I guess it should be possible to pass from the fuse box, through the walls, to my office another wire (ground wire?). I have to check with the electrician...

 

That would most likely be your problem! Something in the sink valve controls is bleeding line voltage into the floating grounds of everything attached to it on that circuit.

Some electrical contractor cheated and didn't do their job properly during the remodel and never put the proper modern 3 wire feedline in and managed to sneak it past the inspector.

 

That would most likely be your problem! Something in the sink valve controls is bleeding line voltage into the floating grounds of everything attached to it on that circuit.

Some electrical contractor cheated and didn't do their job properly during the remodel and never put the proper modern 3 wire feedline in and managed to sneak it past the inspector.

Hi Guys! I´m back!

I managed to get the owner of the building to install an extra grounded wire in all floors of the building.. And now I already have this new ground wire in my fuse box. So now I can have an electrician to extend it to my outlets...


Can I, for instance, as my electric solenoid valve for the sinks has only two wires, can it be wired on the phase wire and ground wire, instead of the phase one and neutral one? (In my country, it used to be commom the neutral be merged with the grounded all way to the electrical company distribution. So we didn´t have an option to use an exclusive ground wire - So all my neutral wires are grounded together at the electrical company).

One more question... it´s a silly one, but, just to clarify things...

Could I wire everything with the phase wire and the ground wire, ignoring the neutral one? What would happen?

Thanks!

 

In the majority of jurisdictions you Cannot use the earth ground as a current carrying conductor, it is only there for safety purposes.
Max.