loop test

[chowbasa]

I have a 60 m run of swa protected by a 30 ma rcd when triying to do a loop test at the furthest end it trips the rcd the tester is a megger cm 500 so it shouldnt trip if I then go to the RCD and do a 15ma test on the rcd it does not trip its getting on my ---- as i have to walk 60 m to reset the rcd.

 

[Big_Spark]

Try this

It may help.

 

[chowbasa]

Looking in the manual is goes off about high leakage current theres only 2 5 ft flouries & 1 emergency light what can be leaking.

 

[Big_Spark]

Looking in the manual is goes off about high leakage current theres only 2 5 ft flouries & 1 emergency light what can be leaking.

READ the manual and you WILL understand why your tripping the RCD. If you cannot, you should not be doing an RCD test in the first place.

 

[chowbasa]

Ive read it and still dont understand.

 

[Big_Spark]

Ive read it and still dont understand.

Go to Page 17 in the manual Chowbasa, it is pdf so I cannot post it here, look in the right hand column, it tells you about the 15mA test..if you read it, you should start to understand.

Here it is..Acrobat Pro is good..forgot I could do this

Earth Loop Resistance measurement at 15 mA
The LOOP 2 kΩ 15 mA range is a high resolution, low current
resistance range. The 15 mA current enables the earth loop
resistance to be measured without tripping all types of RCDs with
a rated current of 30 mA or higher. Tests may be made via
installation sockets with the plug terminated test lead, or at any
other point using the 2-wire lead set. Connections are required to
Line and Earth only.
15 mA - Phase to Neutral or Earth loop impedance
measurement - Power plug method
1. Select (Loop) 2kΩ 15mA.
2. Insert the plug into an installation socket.
3. Supply voltage and polarity are displayed.
4. Press the TEST key. Test progress is displayed.
5. Measured loop value is displayed
If desired the test can be repeated by pressing TEST again.
15 mA - Phase-Earth loop impedance measurement -2-wire
method
1. Select (Loop) 2 kΩ 15 mA.
2. Firmly connect the red lead to phase and the black lead
to earth. No connection to neutral is required.

 

[chowbasa]

The onlY way I could get a reading was to remove the RCD from the circuit being tested. I was then able to get a reading which was ok this points to the RCD being faulty the strange thing is the RCD is located at the feed end of a 60 metre swa cable run, if you tested the RCD here it seemed OK. Im going to have to replace this RCD and try these tests again, better still ill put the RCD at the other endand see what happens.

 

[Big_Spark]

Chowbasa, the RCD is likely NOT faulty.

The 15 mA current enables the earth loop
resistance to be measured without tripping all types of RCDs with
a rated current of 30 mA or higher

It is likely that this RCD will trip regardless, why not use the tester to test the RCD?

 

[chowbasa]

Didnt think of that at the time the RCD was out its back in now. doh!