UPS with step-down transformer attached

[Anonymous user]

I have an interesting little problem that I think I have found a solution to. I have a 208V 20A (L6-20) receptacle that I need to convert to 120V 20A (L5-20) and my idea is to use a APC Smart-UPS XL 3000VA 208V Tower/Rack Convertible (Link: [SUA3000XLT|http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SUA3000XLT]) to connect to the incoming line (L6-20) which then has 4 outputs, 2 x L6-20 and 2 x L6-30. I would then connect a APC 208V to 120V Step-Down Transformer (Link: [AP9621|http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=AP9621]) to one of the L6-30 outlets on the SUA3000XLT to power my telcom cabinet with some L5-15 and L5-20 equipment. The SUA3000XLT will only be providing battery backup power for 10-15 seconds if the power does go out at the facility (A generator will provide backup power in an emergency).

I believe this scenario would work, but would anyone be able to confirm that?

Side note - I am not able to upgrade the 20A circuit to a 30A circuit at this time (L6-20 to L6-30).

[BillP · Accepted solution]

hi,

i think this will work fine but the only thing you need to worry about is the 20 amp breaker on your UPS is what will limit your power/current draw. the 30 amp outlets on that UPS are for convenience only and even though are 30 amp receptacles, it is still limited by the 20 amp breaker/plug type on the UPS. same applies to the step down transformer. it has a 30 amp plug but you cant pull that much since the UPS breaker/plug tpe limits your current draw.

as long as you keep all of this stuff under 16 amps (because of the plug on the UPS and the 80% national electrical code rule), you will be fine.

let me know if you have any other questions.