UPS - input rating vs output load

[Visage]

with a single UPS rated at 8KVA, 230v, stating maximum input current of 44A, would the over current device, cable size etc be based on the 8KVA installed load (the UPS), or, the actual load of 8A, connected to the output of the UPS ?

this is a fixed installation, supplying computer based loads, PCs, monitors of fixed quantity

 

[waross]

After a prolonged outage the input current may go to 44 Amps as the batteries are recharged. You have to use the rated input current for overcurrent and ampacity sizing.

this is a fixed installation, supplying computer based loads, PCs, monitors of fixed quantity

I gotten bit on that line too many times. That's right up there with "The checks in the mail." and "I'm from the government and I'm here to help you."
Bill
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"Why not the best?"
Jimmy Carter

 

[Visage]

thanks Bill

this was my thinking too, what if the customer adds equipment to the UPS load at some future date. Our equipment does have plenty of extension sockets that could have some unknown load plugged into

 

[DanEE]

Did the UPS installation documentation provided by the manufacturer not address this?

My experience with fixed UPS installations and electrical code requirements are that the manufacturers installation documentation addresses requirements that may be unique to the design of a particular UPS and should cover any installation requirements beyond or unique to what prescriptive electrical code requirements would address. The documentation included complete systems installation wiring diagrams and auxiliary equipment required to be part of the fixed installation.

AHJ inspections treat this documentation as an extension of the code requirements above and beyond whatever electrical codes may require for general electrical installation in their inspections.

Much the same analogy as P.E. signed documentation that must accompany custom engineered beams in to be used in a specific building structure.

 

[Visage]

DanEE

yes, the manufacture said I should follow their installed rating of 44A for basing electrical supply, input to the UPS, which is from their manual

 

[waross]

The input current to the UPS will be full rated load plus charging current.

Bill
--------------------
"Why not the best?"
Jimmy Carter