Earth loop tests on circuits with UPS backup

[silver surfer]

What is the proper procedure for ELI testing circuits with UPS back up, ie radial circuits under computor room floors?
Do you test with the mains bypass connected? with the UPS/ mains in normal operation? or in UPS status only?, ie mains failure.
Thanks.

 

[IQ Electrical]

What is the proper procedure for ELI testing circuits with UPS back up, ie radial circuits under computor room floors?
Do you test with the mains bypass connected? with the UPS/ mains in normal operation? or in UPS status only?, ie mains failure.
Thanks.

Any EFLI tests through a UPS will give artificially high readings from the output stage of the UPS.

The test should be carried out on bypass and values should be as expected for the system parameters.

The UPS will be fault limited on battery operation and will usually shut down after say 100ms to protect the inverter and prevent any damage to cables etc. being caused by the fault.

This automatic shutdown is type tested as part of the EN 50091 and EN62040 standards.

 

[silver surfer]

Thanks IQ