Problems testing RCDs/RCBOs

[Betty.Swollocks]

Hi,

My Megger 1553 only seems to want to do the RCD testing part of its functionality, when you use the plug in lead (The one with a standard 3 pin molded plug on the end).
Using the other 3 individual leads achieves nothing and the test fails. I have tried testing at CU and also at a socket outlet and yet the test always fails.
I first tried at the CU and when that failed, I decided to see if it was something I was doing wrongly at the CU (Senior Moment). I went to a socket outlet that I had previously tested successfully with the plug-in adapter, and used the 3 individual leads and a Kewtech plugin that allows you to connect normal leads to a socket outlet. Nothing, nada.

I came across this problem when testing a 6A RCBO fed fire alarm circuit. In the end I just improvised and attached a single socket to the end of the circuit and used the plug-in adapter. Worked as usual and readings were fine.

Any ideas? Duff 1553 or does the RCD testing bit only function via the specialist plug-in lead?

Cheers

 

[Andy78]

Did the meter show that you had full contact with the probes before you tested ?
My first thought would be bad contact/duff leads.

 

[telectrix]

seconded.the 4mm sockets on mine were dirty,causingthe continuity to flop around between 0.03 and 9.5ohms with leads shorted/.worked OK with the plug-in socket.it couldalso be a dry joint on the back of one or more of the 4mm sockets.

 

[Betty.Swollocks]

When using the Kewtech adapter and I switched the meter to a simple voltage reading, it didn't show any issues and registered as seeing mains voltage on the circuit.

 

[Betty.Swollocks]

Can't see Telectrix's reply, theres a sodding advert right over the top of his text and it won't budge. :-(

 

[westward10]

Can't see Telectrix's reply, theres a sodding advert right over the top of his text and it won't budge. :-(

Are you logged in, they should disappear.

 

[Betty.Swollocks]

Well I seem to be as my username appears at the top of the site. Currently using Chrome. Tried in Firefox and IE and got the same result :-(

 

[Octopus]

Sounds like a damaged connector or probe to me

Do you have any mates who have the same model? I would suggest trying another set of leads.... that said they don't last for ever so you'll need to buy some sooner or later!

 

[Betty.Swollocks]

Sounds like a damaged connector or probe to me

Do you have any mates who have the same model? I would suggest trying another set of leads.... that said they don't last for ever so you'll need to buy some sooner or later!

So just to confirm... You should be able to do the RCD tests using the 'usual' leads, not just the plug-in adapter?
As I've never used my 1553 in that way, I wasn't sure if I was trying something that wasn't possible anyway.

Cheers

 

[Octopus]

Yes.... how do you normally test at light fittings? fused spurs?

 

[Andy78]

Are you using the tester as described here ? Not used a Megger 1553 myself.

Residual Current Device (rcd Testing) - Megger MFT1500/2 User Manual [Page 14] - https://www.manualslib.com/manual/952263/Megger-Mft1500-2.html?page=14#manual

 

[Toneyz]

I've got 1552 and use option 1 with red and green leads or 13A plugtop lead I used to have problems testing RCD's at D.B. when rcbo's had white earth lead .I've found that the redesigned leads do not fit in Kewtec socket and lighting adaptors.

 

[telectrix]

OP youcan get a 2 or 3 lead set with 4mm plugs on the load end, and a plug for the 1553 socket next to the one for the 1363 plug lead.( the one the probe goes into) they are all paralleled up inside the tester.

 

[tony mc]

You dont need the black lead attached when doing a RCD test you only need the Red and Green lead plugged in.

Sounds like a connection issue,when you say fail what appears on the screen !

Try testing at the CU with just 2 leads as you should be testing the RCD with no loads attached to the circuit!

 

[Betty.Swollocks]

Yes.... how do you normally test at light fittings? fused spurs?

No you misunderstand me... I can do all other tests fine, and using the normal leads. Because this was the first time I had attempted to use the 'Normal' leads for the Automated 5 test RCD test and not the plug top lead, I wasn't sure if the problem was with the machine or if the 1553 ONLY did RCD tests via the plugtop lead.

 

[Betty.Swollocks]

Are you using the tester as described here ? Not used a Megger 1553 myself.

Residual Current Device (rcd Testing) - Megger MFT1500/2 User Manual [Page 14] - https://www.manualslib.com/manual/952263/Megger-Mft1500-2.html?page=14#manual

Yes. Interesting that the other tests work without issue, using the standard leads, but the RCD ones don't.

 

[telectrix]

are you using all 3 leads for the RCD test?

 

[Betty.Swollocks]

are you using all 3 leads for the RCD test?

Hmm... there is a possibility that I was. Looks like human error is the likeliest cause, not duff leads.

 

[Betty.Swollocks]

Hmm... there is a possibility that I was. Looks like human error is the likeliest cause, not duff leads.

I didn't have the small quickstart guide with me, so might have just assumed (wrongly) that all 3 leads were required. What a schoolboy error. I feel so ashamed.

 

[tony mc]

This might help