Consumer UPSes in commercial colocation

[Zitibake]

Some people want to place a rack-mount UPS in their colocation cabinet or cage, even though their power is already protected by a datacenter UPS. I'm not a fan of consumer UPSes: the reliability is lower than that of a datacenter UPS system, so they could actually cause an outage, rather than preventing one. Customers don't have the batteries inspected, tested or replaced at regular intervals. I've seen malfunctioning consumer UPSes with warped, heat-bloated batteries (e.g. http://www.fourmilab.ch/fourmilog/ar...11/000609.html ). They can release noxious gases into the datacenter. They calibrate or cycle their batteries, causing uneven power use for a cabinet. I also heard (from a fire suppression vendor) that some Fire Marshals require that all UPSes in the datacenter be wired to the datacenter EPO circuit, if the datacenter has water-based fire suppression systems.

Given all that, I'd really like to keep them out. Does anyone here ban small UPSes in the datacenter? Where do you draw the line? For example, there are SANs on the market that will not enable write-caching modes unless they detect that a particular UPS is attached; and what about telco/carrier relay racks with their own -48v DC battery system? Those are VRLA too.

[KenB]

We keep them out, whenever possible, for the reasons you mention. The (US) National Electrical Code has an exclusion for small UPS units (<1500W, I think), but everything larger needs to be connected to EPO. For those who insist, you could draw up a liability waiver, that offers the customer the opportunity to take full responsibility for injury to staff or emergency personnel and/or customer equipment or facility damage, due to rackmount UPS malfunction. Your insurance underwriter might help.

Ken