Testing problems need a little help.

[kes123]

Hi, I am being careful. ok so one probe to earth and one probe to line with the system switched off.

megger set to loop Hi. No reading is given.

 

[malcolmsanford]

Which side of the RCD are you puting the probe son on the supply or load

 

[topquark]

yep. the megger 1700 models are capable of doing a 2 lead soft test, whereas all earlier models was a 3 lead test ( so i am lead to believe, anyway )

Mine (1553) requires 3 leads for a soft test and I had heard that the new ones have a two lead soft test.

 

[topquark]

Hi, I am being careful. ok so one probe to earth and one probe to line with the system switched off.

megger set to loop Hi. No reading is given.

Check which ports on the megger your probes test leads connected to.

 

[Amp David]

Hi, I am being careful. ok so one probe to earth and one probe to line with the system switched off.

megger set to loop Hi. No reading is given.

You mustn't being doing as the others have said.

Put the red probe on the incoming side of the main switch and the gree to the disconnected earth.

Are you testing at the origin or a an RCD protected submain?

 

[kes123]

Ok now I am really confused. the consumer unit is protected by a 100amp rcd.

I am connecting green probe to earth. the red probe to the rdc should this be the live side of the rdc then not the dead side.
my megger is just flashing 55

 

[topquark]

Can we please clarify, when you say the consumer unit is protected by, do you mean the main incommer in the consumer unit is an 100A RCD or is there an RCD between the meter and CU?

Whenever you are testing Ze your whole circuit side of your CU should be off as you've disconnected the main earth for the whole installation! So the only thing that should be live in the CU is the supply side to your main incommer.

 

[flukey]

connect to where your main tail comes in as the other side will be dead

 

[kes123]

Hi think I have cracked it now. I was testing on the dead side of the RCD, now I have tested live side of RCD and my reading is 2.35k does this seem right

 

[malcolmsanford]

Can we please clarify, when you say the consumer unit is protected by, do you mean the main incommer in the consumer unit is an 100A RCD or is there an RCD between the meter and CU?

Whenever you are testing Ze your whole circuit side of your CU should be off as you've disconnected the main earth for the whole installation! So the only thing that should be live in the CU is the supply side to your main incommer.

Ok now I am really confused. the consumer unit is protected by a 100amp rcd.

I am connecting green probe to earth. the red probe to the rdc should this be the live side of the rdc then not the dead side.
my megger is just flashing 55

I asked that in post #13

Kes take a deep breath and look at what you have. Is your RCD external to your CU as we asked, becasue if it is then you will need to do the Ze test on the supply side of this...............ie the side where the tails enter it from the meter.

If the 100mA RCD is in your board, then you will need to switch the RCD off, and where the tails from the meter fit into the RCD you use that LINE. Before though you do anything else get a voltage indicator and start to check, after you have switched the RCD off, what side is dead and what side is live

 

[telectrix]

not for Ze it isn't. are you measuring Ze or PEFC?

 

[topquark]

2.35k what? If you're saying 2.35K Ohms, then no, no matter what earth type you have!

 

[telectrix]

if tat's his Ze, then the earth rod must be a plastic coat hanger.

 

[topquark]

I asked that in post #13

I know and it remained unanswered, sorry for trying to help.

 

[kes123]

To clarify my RCD is external to the consumer unit. The tails that enter the RCD are clearly marked L and N. With megger set to high on loop, I connect green probe to disconnected earth and red probe on to the positive of the tail that enters the RCD and then take the reading.