Time delay RCD

[sparky87]

Hi People,
Carrying out a EIC on a recent cu replacement on a TT system. 100 amp 100MA time delay RCD used up front but cert is asking for time delay in MS- how do i find this out?

Thanks
Adam

 

[Pete999]

Ms ????

 

[sparky87]

rcd time delay in mili seconds?

 

[Pete999]

rcd time delay in mili seconds?

Capital M = Mega small m = mili confusing to me that was sorry for being pedant lol

 

[Leesparkykent]

The operating time at 100% rated tripping current for a BS61008 time delayed rcd is 130-500 ms.

 

[Simonslimline]

Do you own GN3?

This should be an easy one for a qualified supervisor!

 

[sparky87]

I know the trip time etc but cert asks for time delay in Ms but doesn't say on any of the rcds I have access too or looked at on line including manufacture data!. I.E 1Ms or 60Ms etc, think I have found that standard S type rcds have a delay of 200 Ms? anybody confirm?
Thanks

 

[Midwest]

I know the trip time etc but cert asks for time delay in Ms but doesn't say on any of the rcds I have access too or looked at on line including manufacture data!. I.E 1Ms or 60Ms etc, think I have found that standard S type rcds have a delay of 200 Ms? anybody confirm?
Thanks

Have you tested the RCD?

 

[Deleted member 26818]

Conduct a ramp test, then subtract the standard non-time delayed time from the tested time and you will have the time delay.

 

[sparky87]

Have you tested the RCD?

yes and it tripped at 174 ms? how does that help?

 

[Midwest]

At 1 x I delta n? Sorry haven't got the right symbol.

 

[Midwest]

As Lee stated; what does table 3A state?

 

[Octopus]

Which BS number RCD are you talking about?

 

[sparky87]

Which BS number RCD are you talking about?

61008 100A 100MA time delayed (s type) RCD

 

[sparky87]

At 1 x I delta n? Sorry haven't got the right symbol.

yes you only test at 1x, but its not the tripping time I'm questioning, its the time delay time (i.e how long it holds back from tripping)

 

[happysteve]

I think you're overthinking this.

A BS EN 61008 delay "S" type RCD should trip at x1 I delta N between 130ms and 500ms, as per table 3A in appendix 3 of BS 7671 (as others have said).

So it "holds back from tripping" for anywhere between 130ms and 500ms.

The boxes on the EIC are there to establish that verification has included a comparison of results with relevant criteria.

As you say the next box is "Measured operating time at I delta N" which you have measured at 174ms.

This complies with the specifications of the RCD. Job's a good 'un.

In terms of what number to put in the box: I would put "130-500." A measured time below this would be too short. A measured time above this would be too long.

 

[Midwest]

Question answered then?

 

[davesparks]

I'm throughly impressed by the talking certificate!

But anyway, why do you need to record the time delay for a non adjustable RCD?

Blindly following what is written on a form without understanding why you are doing it is just plain ridiculous!