EICR IR testing on whole installation with circuits protected by RCBOs

[Bradley6969]

EICR IR testing whole installation with circuits protected by RCBOs...

Say it's a single phase consumer unit, plain main switch no RCCBs, all circuits protected by RCBOs,

Is this method acceptable?....

L+N to earth only.
Main switch off (safe isolation), all breakers on.
Temp link neutral bar to load side of one of the breakers or main switch?
Disconnect any RCBO earth fly leads from the earth bar, reconnect cpcs if neccessary
Leave the neutral fly leads connected.
IR test between earth bar and L/N 500v?

 

[westward10]

I personally wouldn't do this. I would do individual circuits as the manufacturer will state they should not be subject to insulation resistance tests.

 

[Octopus]

Ditto

A global IR on a system with rcbo's is likely to give very odd readings....

 

[Bradley6969]

So each RCBO one by one is better outcome? It's a 7 way board with 3 mcbs and 4 RCBOs so mcbs I can do all at once?

 

[westward10]

The rcbos will still be in the board just do them all individually. I see you have no electrical qualifications.

 

[Risteard]

Personally I would prefer to do the entire installation/DB in parallel rather than each circuit separately. If you don't then you need to calculate the resistances in parallel to determine whether it is acceptable.

However this approach can sometimes be problematic with RCBOs, although usually you should be OK after disconnecting functional earths if applicable. (Don't forget to reconnect them though!)

 

[westward10]

Personally I would prefer to do the entire installation/DB in parallel rather than each circuit separately. If you don't then you need to calculate the resistances in parallel to determine whether it is acceptable.

However this approach can sometimes be problematic with RCBOs, although usually you should be OK after disconnecting functional earths if applicable. (Don't forget to reconnect them though!)

Is that in compliance with manufacturers advice?

 

[Risteard]

Is that in compliance with manufacturers advice?

Depends on the manufacturer. Although it should be remembered that BS7671 requires the installation (or distribution circuit with all final circuits connected for larger installations) to be tested in parallel, or if done separately then the resistances in parallel to be calculated. The figures quoted for insulation resistance are for the installation (or DB).

 

[westward10]

Doubt any manufacturer would recommend IR tests through an rcbo.

 

[Risteard]

Doubt any manufacturer would recommend IR tests through an rcbo.

You aren't testing through it if you are testing live conductors to earth with the functional earth disconnected if it exists.

 

[HandySparks]

I wouldn't have a problem doing a global L+N to E IR on RCDs or RCBOs, providing that any earth reference wires are disconnected. If all the devices are closed, there can't be any voltage difference between any of the RCD or RCBO terminals, so no possibility of damage or of incorrect readings.

 

[chris day]

IR testing can be useful on existing installations as you can see any potential problem however i dont do IR testing on large commercial buildings as there is no real point, all you need is a hidden RCD socket to mess things up