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?

 

[DPG]

I'm still confused. Do you not know what the regs require, or do you not get the seconds/milliseconds thing?

 

[Bradley6969]

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

Thanks is there a way to understand how to set the time delay?

 

[Bradley6969]

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

Thanks is there a way to understand how to set the time delay?

 

[Bradley6969]

I'm still confused. Do you not know what the regs require, or do you not get the seconds/milliseconds thing?

I’m not sure what the regs require? I know how to set trip current but not the trip delay

 

[westward10]

First you need to know what function it is required for. Secondly you need to consider upstream devices and how they are operating then the vigi module can be set to ensure coordination is achieved.

 

[Bradley6969]

First you need to know what function it is required for. Secondly you need to consider upstream devices and how they are operating then the vigi module can be set to ensure coordination is achieved.

It’s TT system so this is the upfront RCD, all there is down stream is 30mA RCBOs at boxes protecting sockets

 

[Bradley6969]

So top dial trip current I can set anywhere from 30mA to 10A
Bottom dial time delay I can set from nothing to 3 seconds

 

[Bradley6969]

So my final circuits are no greater than 32A on TT which is 0.2 seconds so I can set the trip delay to 0.3

 

[westward10]

What is the mccb which the module is fitted to supplying.

 

[Deleted member 26818]

So my final circuits are no greater than 32A on TT which is 0.2 seconds so I can set the trip delay to 0.3

No, of course not.
You have to set it to 0.2, or less.

 

[Bradley6969]

What is the mccb which the module is fitted to supplying.

Supply to 3 X BS88 in same panel, then onto some boxes with 16A sockets and relevant 30mA RCBOs in boxes

 

[Bradley6969]

No, of course not.
You have to set it to 0.2, or less.

So just set to your diconnection time?

 

[Deleted member 26818]

So just set to your diconnection time?

Yes, you can’t set it to higher than the maximum disconnection time allowed.

 

[Bradley6969]

Thanks guys really appreciate your time

So if it was more than 32A TT system I’d set it to 1.0 second for instance?

 

[Deleted member 26818]

Thanks guys really appreciate your time

So if it was more than 32A TT system I’d set it to 1.0 second for instance?

If you were using it to protect distribution circuits or other circuits greater than 32A, yes you would set it to 1s.