RCBO 5In trip times.

[Crosswire]

^^^which is what i've been trying to explain for the last half hour lol.

Maybe, but not very clearly.

But thanks for that, it will definitely save me a lot of time in the future.

The only issue that remains is that of the OP. Why the difference in disconnection times with the the circuit connected or disconnected?

Any ideas?

As regards to ballasts etc "corrupting" the readings, if they are part of the circuit, they should conform to disconnection times.

Or am I wrong again?

 

[Guest55]

FFS
I answered that in my first post.
Why do i bother.

 

[tony mc]

I have to agree with biff on the above.

RCD test should be done with loads disconnected and a EFLI test prior to RCD testing.

As mentioned the times can be alot different if equipment is left connected.

GN 3 Rcd testing also makes mention of this.

 

[Crosswire]

FFS
I answered that in my first post.
Why do i bother.
View attachment 13794

Well not really. You said components of the circuit would "bugger up" the readings. I was under the impression the entire circuit should be tested, and conform.

Perhaps I am wrong and am willing to admit that. However, the NICEIC forms I fill in have a seperate box for the RCD disconnection times for every circuit. So when I fill these forms in, I measure the RCD connection times for each circuit, and record them appropriately.

Perhaps I should correct for ballasts and switches corrupting my results in the future. Do you have the correction factor for this as it will be very helpful?

 

[Crosswire]

I have to agree with biff on the above.

RCD test should be done with loads disconnected and a EFLI test prior to RCD testing.

As mentioned the times can be alot different if equipment is left connected.

GN 3 Rcd testing also makes mention of this.

Ok fair enough. I have pulled the GN3 off the shelf and it does say the load should be disconnected for the test. I was wrong on this point but my instinct still tells me the whole circuit should be tested. In the future i will test at the CU on a standard split load board and simply duplicate my results for the number of circuits that the RCD is protecting.

Sounds like a cowboy job to me, but if that is what is required then that is what I will do. Thanks to everyone who set me straight, as I was doing a lot of (apparantly) needless work.

 

[Strima]

We're only required to test the device, not the circuit for disconnection times of RCD/RCBO. I can see the reasoning behind testing the whole circuit but that is why we do R1+R2 tests to ensure we have continuity that will meet with disconnection times.

If you start taking into account ballasts & transformers where will it end?

 

[Strima]

It's just clicked, the test meter sends a 'pulse' to initiate the trip. Ballast/transformers/loads can absorb some of this 'pulse' and give spurious readings.

I think...

 

[Crosswire]

It's just clicked, the test meter sends a 'pulse' to initiate the trip. Ballast/transformers/loads can absorb some of this 'pulse' and give spurious readings.

I think...

Sounds reasonable. And I know I was (am still) wrong, But if they absorb leakage in a test situation, might they also absorb leakage in a genuine fault?
I am not trying to flog a dead horse but just think testing an RCD in 'laboratory conditions' defeats the point of the testing.
Anyhow, I concede defeat on this issue as the powers that be have ruled otherwise.
Saves me a lot of time

 

[Strima]

Consider putting a nail through a cable, the fault will be greater than 30mA.

 

[Johnny-G]

However, the NICEIC forms I fill in have a seperate box for the RCD disconnection times for every circuit. So when I fill these forms in, I measure the RCD connection times for each circuit, and record them appropriately

Whilst each line has provision for RCD times you only have to record the times on the line the RCD itself is on, unless you're saying that you don't actually have RCD's on their own line?

 

[PEG]

With Biff on this one,RCD test is just that,a test on a specific device.IR and R1 / R2 tests confirm satisfactory operating criterea of device.If you had to test it with loads connected,which would you choose to be connected/on/off or any combination?

 

[Crosswire]

I do have them on their own line, but have always recorded the disconnection times on the circuit line, as this is where I measured it , Do you record it on the RCD line and put N/A on each circuit line?

 

[Guest55]

Ok fair enough. I have pulled the GN3 off the shelf and it does say the load should be disconnected for the test.

So you had the info all along and didnt bother to follow it ????

Then you claim my explainations were unclear in a completely ungrateful manner after i spent over an hour on the thread ???

Now youre still reluctant to do the testing as advised even though its alot quicker and easier just because you dont understand the science behind it ???

You're just all over the place to be honest.

 

[Johnny-G]

I do have them on their own line, but have always recorded the disconnection times on the circuit line, as this is where I measured it , Do you record it on the RCD line and put N/A on each circuit line?

I just leave it blank, but that's because I only test the RCD, not each circuit

 

[Crosswire]

With Biff on this one,RCD test is just that,a test on a specific device.IR and R1 / R2 tests confirm satisfactory operating criterea of device.If you had to test it with loads connected,which would you choose to be connected/on/off or any combination?

Usually on as this mirrors a real life situation, where a fault may potentially develop.

 

[Crosswire]

So you had the info all along and didnt bother to follow it ????

Then you claim my explainations were unclear in a completely ungrateful manner after i spent over an hour on the thread ???

Now youre still reluctant to do the testing as advised even though its alot quicker and easier just because you dont understand the science behind it ???

You're just all over the place to be honest.

Get over yourself. This forum is a place for discussion of technical issues. Please do not take every question raised as a personal attack. I simply debated a matter of recording disconnection times in the hope it would stimulate an intelligent debate.

If you find this offensive, simply do not answer. I do not owe you any kind of gratitude for joining the discussion. I queried a method of recording disconnection times which was raised by the original poster, people posted various answers, I re-checked my literature on the subject, and admitted I was wrong.

What do you want ? A bunch of flowers?

With regards to your comment, there is no 'science' behind sticking probes onto the RCD at the CU. A child of three could do it.The most complicated thing about electrical installations are the regulations that govern it.

 

[Guitarist]

biff and the boys are totally right here...
1) Test your R1+R2 to ensure the circuit complies with EFLI
2) Test the RCD at the CU with loads disconnected
3) Assuming they conform, put the readings on the test sheet. Personally I put the same reading down for each line related to said RCD, tho many do the " sign. Don't put N/A, as it IS applicable.

All sorted now, sleep well

 

[Guest55]

Get over yourself. This forum is a place for discussion of technical issues. Please do not take every question raised as a personal attack. I simply debated a matter of recording disconnection times in the hope it would stimulate an intelligent debate.

If you find this offensive, simply do not answer. I do not owe you any kind of gratitude for joining the discussion. I queried a method of recording disconnection times which was raised by the original poster, people posted various answers, I re-checked my literature on the subject, and admitted I was wrong.

What do you want ? A bunch of flowers?

With regards to your comment, there is no 'science' behind sticking probes onto the RCD at the CU. A child of three could do it.The most complicated about electrical installations are the regulations that govern it.

Maybe you should give testing a miss till you know what youre doing.
And i prefer chocolates.

 

[kingeri]

Been an outside observer on this one til now.....but the Crosswire has certainly lived up to his name in this thread! The RCD testing we do is just that....a test to confirm that the RCD works! The circuit itself has already been tested by the time you do the RCD test. The testing done on the circuit to verify EFLI ensures that the fuse or MCB will operate (or circuit breaker element of the RCBO) within the required time. The RCD is there as additional protection, and as long as you check that it's working, then everything's fine!

 

[Crosswire]

Maybe you should give testing a miss till you know what youre doing.
And i prefer chocolates.

Choccies it is then