SW 4048 Schneider Electric Hum Noise

b. ecologìcAllb. ecologìcAll Registered Users Posts: 26 ✭✭✭
I installed an SW4048 about 6 month ago. at random times, it make a very loud hum sound.
AC out is feeding a GE 8/16 circuit panel with only 3 breakers, one for lights and fans, one for modem and laptop, the other one for a Samsung refrigerator.
when the inverter makes de loud hum sound, if I turn of ACin breaker, the sound stops
If I turn back on ACin breaker, sound stars again
If I turn off the GE breaker for the refrigerator, the sound stops

While in off-grid mode, the refrigerator breaker is on with no hum sound

what could be? 
the neighbor is connected to the same utility pole, he have an XW6048 with no problem at all

two different electrician has verify the ac and dc wiring and the said all the wiring its ok

the sound is while in Grid Support
if I turn off grid support the sound disappears, but, then the client is taking power from the grid not from the solar panels
4 Solar World 285 with an MPPT60

I have trouble shooting this for 6 month and running out of options

could be firmware?
could be a SW?
could be the refrigerator? its new

any help will be appreciated 


  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    A wild guess, not GT so: Have you checked the torque on all connections, especially the ground connections to do with the grid tie side?
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • mike95490mike95490 Solar Expert Posts: 8,761 ✭✭✭✭✭
    My XW lets loose with a big hum as loads cut in and out.  It's likely just transformer hum as the loading increases.  I can hear it vary as my front load washer runs and reverses.  When the pump kicks on, it's got a big buzz for a second, then settles down to a low hum.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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  • Dave AngeliniDave Angelini Solar Expert Posts: 5,182 ✭✭✭✭✭
    edited September 2016 #4
    You should check the serial # as there have been a few firmware changes. One was pretty big!
    Since the Connext SW can't sell and only support I would say the noise you are hearing is AC1 doing it's thing, charging the battery from the grid. You are welcome to e-mail me for more. good Luck!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
    E-mail [email protected]

  • b. ecologìcAllb. ecologìcAll Registered Users Posts: 26 ✭✭✭
    thanks for your suggestions 

    all wiring have been re checked several times, but the "ground rod" because it is under concrete, under the utility meter. 
    the neutral and ground inside utility meter base have been checked 
    all house appliance are working very well with no signs of a loose ground or loose neutral

    loads, are only a refrigerator, lights and fans, modem and laptop
    average load is less than 500 w. typically 300w 

    battery charging from the SW inverter is only set to 5%, to reduce utility usage

    have not check yet for firmware updates, to do list

    strange thing of all, the end of the world sound stops if ACin is turned off

  • Dave AngeliniDave Angelini Solar Expert Posts: 5,182 ✭✭✭✭✭
    I do not think that is strange, it is the grid :) Set the grid charger to 0%
    It would help if you describe the system?
    Sometimes the only way to check a UFER ground is to drive a ground rod in and use that.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
    E-mail [email protected]

  • softdownsoftdown Solar Expert Posts: 3,137 ✭✭✭✭
    If you have dry, sandy soil it is not unusual to need two grounding rods. I bought three for my electric fence due to the unusually dry and sandy soil.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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