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We have 2x APC symmetra LX 16kVA units running at the moment and have read (in Eaton's documentation) that their UPSs can have a common synchronised output (based on input phase or set phase with a master/slave clock type arrangement) -

We would like to connect our two UPS units together as at the moment one is a "cold" manual switch standby unit.

Do APC offer a synchronised phase output for N+1 redundancy between chassis and if so are there any special units required to join the outputs or can a standard tie-cabinet be used?

APC's docs aren't so clear on connecting modular (symmetra) UPSes to a common output.

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This is really an APC support issue, given the scale/class/cost of these units. – ewwhite Oct 3 '13 at 15:09
Actually it is a "read the marketing and technical baseline material". Like the one the OP even linked to that is VERY clear on the different scenario. I could add, snippily, for someone who knows how to read such diagrams - and anyone else should not make such a decision. – TomTom Oct 3 '13 at 15:11
up vote 4 down vote accepted


I.e. unless noted otherwise, you must assume that the output inverters of your UPS do not support this configuration.

As it's already been said; best go talk to APC to get all the answers you need.

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Check diagram 2.7 in the link you provided.

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+1 That works, too :) – ewwhite Oct 3 '13 at 15:15
Fig 2.7 simply shows a Single UPS, under the "Possible Upgrades" section - "on site by connecting several identical UPS units in parallel" - without any mention of any modules etc that may be needed. I think you are referring to Fig 2.8 - this is applicable to MGE units only, Fig 2.11 shows a solution that applies to our units. However searching for Symmetra Static Switch Cublice gives no relevant results. – Myles Gray Oct 3 '13 at 15:22
Then - cough - talk to your sales representative. Get an offer for the configuration you want. Let people at APC make the work they get paid for. – TomTom Oct 3 '13 at 15:31

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