ELECSA Certification Scheme Elecsa assessment

[ashdog]

Hi Chaps,
Had my 3rd assessment on Tuesday ( which i passed) and i was asked why the trip times for the RCD ( x.5 x 1 and x 5) were the same for all circuits.
I said him i was told to test the RCD at the board and record those times for all the circuits covered by that RCD, he asked who had told me to do it this way and i said it was the chap who took my last assessment. He said this was wrong and i should test every circuit controlled by the RCD.

Which way do you do it?

 

[Sintra]

The true characteristics of an RCD can only be tested at the RCD with no loads connected.

 

[Des 56]

Assessors are like all of us,we dont know it all

In this instance he is wrong

As sintra rightly explained,an rcd has a characteristic that can be affected by connected loads

The rcd does not change those characteristics when different circuits are tested
The circuits themselves may cause different readings because of connected loads
Test at source and apply those results to all protected circuits

 

[ashdog]

Sintra and Des thanks for that, i did think the same thing but as it was my assessment just nodded in agreement

 

[ezzzekiel]

theyre usually not trying to trip you up or cause trouble, like building inspectors sometimes its best just to nod your head and smile

 

[Peedy17]

Every assessor I've ever had has contradicted the previous one

 

[softail]

The true characteristics of an RCD can only be tested at the RCD with no loads connected.

does that mean you unplug everything first???

 

[SirKit Breaker]

Hi Chaps,
Had my 3rd assessment on Tuesday ( which i passed) and i was asked why the trip times for the RCD ( x.5 x 1 and x 5) were the same for all circuits.
I said him i was told to test the RCD at the board and record those times for all the circuits covered by that RCD, he asked who had told me to do it this way and i said it was the chap who took my last assessment. He said this was wrong and i should test every circuit controlled by the RCD.

Which way do you do it?

I was also told on my fourth Elecsa assessment to do the RCD test the same as you. However i do check the RCd operation at 1x on each circuit just for peace of mind. In his ( the assessor) words it is much easier to find and replace a faulty RCD before all the breakers are fitted and wired up.

 

[ThomasElectric]

Great question, I was always taught to test at source only, and the reasoning given was that as long as all previous tests have passed, i.e IR, ohms etc, then you know your circuits are fine so testing RCD at source will only be required to verify RCD is operating correctly.

 

[acat]

Sintra and Des thanks for that, i did think the same thing but as it was my assessment just nodded in agreement

Sometimes they do that just to see how confident you are in your knowledge and judgement. On my first assessment Instead of shorting out at the CU I removed the cables and put them in a choccy he said I should have shorted them out I said no safer this way especially if cables for any reason were forgotten or I fell ill and customer turned supply on. My bottle was going but he just smiled and said yes you are quite correct.


Chris