Checking earthing on the line

Discussion in 'BSNL broadband' started by goodyet, Jan 2, 2013.

  1. goodyet

    goodyet Member

    My DSL is very unstable. It seems that there must be earthing/grounding on the line. The lineman does not have the meter to check it. So can I use a multimeter to check grounding?
  2. nevinjohn

    nevinjohn Active Member

    Are you trying to check the ground for telephone line, or the power adapter? As far I know, telephone poles are grounded, not the line itselt. As you see, theres onle + and - for it, and it carries 48 - 70 V DC. What you must be checking should be the line disturbances.

    On the other hand, just to check the ground on the mains...
    Be careful as you are doing this.
    Connect a LED between the Earth and -Ve (neutral) of the 3 pin plug. (No need to switch on). The LED should glow. This is the simplest test. Once again you need to determine the -ve hole. Use a tester for determining this. The tester should glow only for +ve (hot line). So, determine the line where the tester doesnt glow. This is the neutral line.
    Usually the left ones are neutral, but as always, make sure by using a tester.

    For tesing with multimeters..
    Put the selector switch to AC (lowest ranfe 0-50V). Connect the terminals between neutral and earth. It should show a reading netween 1 -5 Volts.

    If a RCCB/ELCB is installed in the electrical panel, performing the above tests should cause it to trip.
    This is okay, which indeed shows that the earthing and connections are good. If tripped, reset the same.
    The groundin is fine, apparently most of the Indian homes lack this security feature, and instead relies on the old fashinoned fuse box!
  3. goodyet

    goodyet Member

    Its the telephone line. If it gets grounded between my house and telephone exchange, then the DSL does not work. Linemen use a meter to find out if the telephone cable pair is exposed to the ground or if it comes into contact with other metal objects. Our exchange line man does not have that meter. So I thought if I could use the multimeter to check if the line gets grouded on its path to my house.
  4. ramitzar

    ramitzar New Member

    Is the Dial tone clear on your phone line ?
    If clear then the insulation of cable pair running to your premises might be low.
    DSL link issues may also crop up if there is foreign potential(due to faulty joints or sulphation) on the line or your modem is faulty.
  5. nevinjohn

    nevinjohn Active Member

    What ramitzar said is right. If you get the disturbances in the telephone as well, its probably the line fault... And no, you cant check that with multimeter unless you know the line parameters.

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