Earth leakage and EICR's

[cprfenom]

Just want to than you for your advice.

It is clear that I really cant explain myself, and that isn't helping you to aid me.

Personally I have never seen an RCD trip on a no trip before when it hasn't been a faulty RCD. I also understand that my terminology is not great, and that must be frustrating.

The circuits I was testing normally have several computers, florescent tube fittings and 12v transformers on it. When testing the circuits, they were all disconnected and all readings were fine. I then reconnected and moved on to an under floor heating circuit, disconnected the load side of the FCU and tried to do the Zs test at this point the RCD tripped. If I turned off all MCB's it still tripped, if I removed all the nuetrals for the circuits Im not testing, the readings are good.

The original point for the EICR is that it by design has 15mA leakage and was strictly asking if this was a c3 with further investigation, or should I just leave it as is.

If this is still confusing, then I will not waste anymore of your time, but thank you for not being nasty about it.

 

[Engineer54]

Just want to than you for your advice.

It is clear that I really cant explain myself, and that isn't helping you to aid me.

Personally I have never seen an RCD trip on a no trip before when it hasn't been a faulty RCD. I also understand that my terminology is not great, and that must be frustrating.

The circuits I was testing normally have several computers, florescent tube fittings and 12v transformers on it. When testing the circuits, they were all disconnected and all readings were fine. I then reconnected and moved on to an under floor heating circuit, disconnected the load side of the FCU and tried to do the Zs test at this point the RCD tripped. If I turned off all MCB's it still tripped, if I removed all the nuetrals for the circuits Im not testing, the readings are good.

The original point for the EICR is that it by design has 15mA leakage and was strictly asking if this was a c3 with further investigation, or should I just leave it as is.

If this is still confusing, then I will not waste anymore of your time, but thank you for not being nasty about it.

If you have a 15mA background leakage, i'll ask if high integrity earthing has been applied to these circuits?? Many here would say that circuits supplying primarily IT/computer loads shouldn't be provided with RCD protection, but that's open for discussion....

 

[cprfenom]

If you have a 15mA background leakage, i'll ask if high integrity earthing has been applied to these circuits?? Many here would say that circuits supplying primarily IT/computer loads shouldn't be provided with RCD protection, but that's open for discussion....

High integrity earthing has been applied. Oddly enough the two RFC that supplied the computers were mixed up and missing one leg at the start.

 

[telectrix]

you could bridge the RCD to get your Zs readings on high current. don't forget to remove the bridging links immediately after, though.

 

[Engineer54]

Well if high integrity earthing has been applied, why are you questioning the 15mA inherent leakage?? If RCD has also been provided then as stated early on, test the RCD at it's disconnected load terminals!! You only need to test the RCD device itself, ''NOT'' the circuit or circuits that it is protecting. Never test an RCD downstream on the circuit wiring when conducting official results that will form part of a test report. Fine for fault finding and the like, but not for testing the permissible operational parameters of an RCD device!!