RCD Help

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ecasam

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I have two circuits protected by 30mA RCD. These are in a second CU where the main switch is the RCD. One circuit gives a reading of 35ms @ 1x and the other gives 25ms @ 1x. Both give 10ms @ 5x. Please can you tell me which reading do I put on the EIC in the main switch section.

 

sysparks

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Its highest reading for the box near main switch.

(Its usually always the highest reading for everything i.e. worst case scenario)

 

windycom

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Agreed that the highest value is nearly always recorded but here we are talking about different values for 2 different devices. The Main switch section of the EIC refers only to the main switch so surely the reading from that device should be recorded. Please correct if I am wrong.

Regards.

Or are you saying the main switch is an RCD and there are 2 other rcd circuits ?

 

windycom

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Just read your query ont he other channel. Now I understand.

Your 2 circuit RCD results have nothing to do with your main switch. You have to test the rcd main switch separately and record accordingly. Slipshod was giving you good advice, you are testing the device in each case, nothing to do with the impedances of the circuits they are attached to.

 

sysparks

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Well iv been getting that wrong for years then!!

:p

 

the doctor

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hi

the 2391 practical PIR rig has a single phase rcd main switch with 3 circuits attached. the norm is to just test the socket outlet circuit and triplicate the trip times across all 3 circuits.

you will find differences in trip times but when confronted with the maximums and the actual times it isnt worth measuring....

 

windycom

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I'm with it now, I thought he had a board with 3 RCDs on it. Thanks Doc. :)

 

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