MCCB with RCD settings

[Bradley6969]

MCCB with RCD bolt on, anyone know how to work these settings out? Ignore settings now but this is upfront RCD TT system so I want to top one to be 0.3 for 300mA but unsure on bottom?

 

[westward10]

That is commonly called a vigi module. You will notice when set for 30ma there is a line down indicating to set to no delay so additional rcd protection is provided.

 

[Bradley6969]

That is commonly called a vigi module. You will notice when set for 30ma there is a line down indicating to set to no delay so additional rcd protection is provided.

Yes I’ve only seen a couple of these, on another vary similar model it also has the option for ON and TEST which is a good feature

 

[Bradley6969]

So does that acheive disconnection times satisfactorily now that you have changed it to 3 x the original ma? Is it not the case if it is tripping that some investigation may be due? Maybe IR tests if it is possible?

Yes all sub circuits and feed from mains all tested fine with IR, now set to 300mA it’s all fine there’s discrimaination now 300mA to 100mA and so on, just didn’t understand the bottom dial

 

[Bradley6969]

So does that acheive disconnection times satisfactorily now that you have changed it to 3 x the original ma? Is it not the case if it is tripping that some investigation may be due? Maybe IR tests if it is possible?

Yes all sub circuits and feed from mains all tested fine with IR, now set to 300mA it’s all fine there’s discrimaination now 300mA to 100mA and so on, just didn’t understand the bottom dial

 

[PEG]

Out of interest,what did you set the delay,to?

 

[Taylortwocities]

You don’t discriminate RCDs on the mA trip current, you discriminate on the basis of time.
That is what time delay RCDs are for.

 

[Bradley6969]

Out of interest,what did you set the delay,to?

It’s at 1

 

[Bradley6969]

Has anyone set one up before and could tell me? Or know how to

 

[Deleted member 26818]

Has anyone set one up before and could tell me? Or know how to

???

 

[DPG]

It's a wind up this one. Guaranteed

 

[Bradley6969]

It's a wind up this one. Guaranteed

It’s the bottom dial I can’t understand? So it just works on disconnection time but in milliseconds? So say I have no greater than 32A final circuits on TT which is 0.2 seconds then what do I set it?
No ---- take, spark I work with doesn’t know either and he’s just guesses where as I’d like to know how and why it’s set like that

 

[DPG]

But you were asking what delay a TT circuit should be set to. Are you saying you know this, but need to convert seconds to milliseconds?

To answer that, there are 1000mS in a Second.

 

[Deleted member 26818]

I think some clarification is needed.
Why are you installing this device, what is it intended to provide protection for?

 

[Yozza19]

It is a variable earth leakage modual that is used with a mccb eather bolted on or using a shunt trip module

The top part is to set trip current
Bottom is to set a time delay

They are mainly used on sub circuits or large motors ect were the time delay can offer some sort of discrimination

Remember earth leakage is cumulative

 

[Bradley6969]

But you were asking what delay a TT circuit should be set to. Are you saying you know this, but need to convert seconds to milliseconds?

To answer that, there are 1000mS in a Second.

Ok so it’s TT, in this panel you have Main MCCB/RCD one in picture then 3 X BS88 fuses which feed some electric boxes with 16A sockets with relevant 30mA RCBOs