Five Steps to consider for Switching UPS into bypass Operation
In order to ensure availability for critical load and safe transfer to and from bypass
The following steps should help
1) Check whether any service advisory is in effect for bypass operation for that particular UPS, pertaining to any particular fault before considering bypass operation.
If not sure consult the escalation teams.
2) Consult the customer and attain formal approval
Please make sure that the customer is aware that in bypass operation the Load is directly powered from the mains and hence their critical load is open to supply variations and disturbances. Hence customer needs to take the required precautions as per their company protocol.
3) check with the customer whether the site conditions are ok for bypass operation.
I.e. no known maintenance work happening upstream and the input supply is not likely to be disturbed.
4) Switch the UPS to internal bypass first
This would normally check whether the input supply conditions are within bypassing limits before transferring the load to internal bypass.
5) Switch to external maintenance bypass as per the documented procedure specific to the product.
a) For Symmetra Single phase products please do not disturb the input breaker while on maintenance bypass
b) For SURT products operate the slide switch (command bypass if slide switch not available) to put the UPS into internal bypass and then operate the external bypass switch on the bypass panel (if available)
c) For Silcon, SUVT and Symmetra PX follow the documented procedure
e) For parallel units when one unit is switched to bypass the other unit also switches to bypass