Data Center EPO

[bward]

Short version: Does a data center, built to 1996 NEC code, need to have a mushroom-type EPO button, or does a readily-accessible main breaker in a panel qualify as an approved disconnecting means?


Long version:

I've got a small data center that I've recently been doing some upgrades to (mostly pulling Cat5/6 and fiber).

There was a brief power outage (confirmed it was a utility problem) that took down the whole room.
Since I'm here, I was asked to have a look at things to see why it happened.

The data center is powered by an ancient UPS battery system. I've determined that that system failed and needs to be replaced, as it did not protect their equipment from the outage. Up to the client whether they want to or not.

Now to my question, I noticed that the data center room itself does not have an Emergency Power Off (EPO) button anywhere. There is a shunt trip on the main breaker to the room, but it's not hooked up to anything!
Also, the UPS room/battery room has an EPO, but it's a keyswitch, not a mushroom button like I usually see. Also, the key is missing...

This is in New York City, so 2008 NEC currently. I've read through Art 645, 685, and NFPA 75 (75-2009 is the earliest I could find), the requirement for "disconnecting means" is pretty vague - seems to be up to the AHJ inspector. The systems were installed in 1999, and last upgraded (but not replaced) in 2002. I believe the 1996 NEC was current in NYC at the time the room was installed, so I've read that version too.

The 1996 NEC, Art 645.10 says "A means shall be provided to disconnect power to all electronic equipment in the information technology equipment room. ... The control for these disconnecting means shall be grouped and identified and shall be readily accessible at the principal exit doors."

Hoping someone here who does power wiring to data centers could weigh in on this. Is the data center room required to have an EPO button installed given that it was built in 1999 (1996 NEC) or does the main breaker in the panel satisfy the requirement? (The panel is within a few feet of the door.) If it must be a separate switch/button, can the EPO in either the data center or the UPS room be a keyswitch, or must it be a single-action mushroom type? Does the EPO in the data center have to disconnect the batteries in the UPS room as well, or can it just trip the main breaker, after the ups? (The EPO in the UPS room must disconnect the batteries, as I read it.)

Thanks.

(Sorry if this double-posts, got logged out while typing.)

 

[iwire]

The 1996 NEC, Art 645.10 says "A means shall be provided to disconnect power to all electronic equipment in the information technology equipment room. ... The control for these disconnecting means shall be grouped and identified and shall be readily accessible at the principal exit doors."

Article 645 of the NEC is voluntary you do not have to use it.

Some people choose to use article 645 because it allows the use of flexible wiring methods in place of hard wired circuits.

On the other hand if the wiring methods used are standard chapter 3 methods you do not have to comply with 645 and the need for an EPO.

How is this room wired?

Does it have ventilation dampers etc to keep it separate?

Is it only accessible to the workers who need to be in there?

 

[ron]

I am in agreement with iwire.

645 is optional. The language in the code indicates in some form or another (changed over last several cycles leading up to 2008 and beyond) "This article shall apply, provided all of the following conditions are met: ". If you don't meet those pre-requisites, such as a disconnecting means (EPO), then the article doesn't apply and you have to use regular Chapter 3 wiring methods, etc.

The liability of having an EPO is not worth the few leniencies 645 allows.

 

[bward]

Thanks for the quick replies guys.

Most of the rack PDUs are attached to overhead junction boxes using flexible metal conduit (I won't say all, because I haven't looked at all the racks). Then it's EMT from the j boxes to the panel.

There are ventilation dampers (although they are closed every time I've been there...), and at one point the room had halon-type fire suppression. I believe that's been removed and replaced with pre-action water sprinklers.

The room is supposed to be off-limits to unauthorized personnel. Only building maintenance and security are supposed to have keys to the room. Contractors sign out the key from security every morning when they're on-site.

So, it sounds like the wiring methods are the determining factor regarding whether 645 applies? I.E. if they used SJ cord and connectors to connect the racks to overhead receptacles, or if they had under-floor wiring?

 

[ron]

So, it sounds like the wiring methods are the determining factor regarding whether 645 applies? I.E. if they used SJ cord and connectors to connect the racks to overhead receptacles, or if they had under-floor wiring?

There are several ways it can be done which is still compliant to the 1st four chapters of the code and not need the leniencies found in 645 (except cords under the raised floor).

 

[arion]

as far as epo panic switches at the exits is concerned those are an open invitation to costly mischief. only install them if it is required by company safety regulations or city fire code. and i hope someone has some serious insurance and a really good data recovery service if water fire suppression is present. those are the kiss of death for data centers i have been called on 2 times to try and bring servers back online after such a system was activated. you couldn't salvage any of them and the loss of data on the drives was substantial. the 1st lost all the data that was not archived offsite. the 2nd site was brought back online using 4 servers that somehow missed getting drowned. but it still had a data casualty factor of 87% loss. they did not have any property insurance coverage on the hardware they paid the entire the 4 million replacement cost . the other data center was owned by Edward Jones investments. that was such a mess they hired 4 contractors to clean it up and rebuild the systems.
they had some heavy insurance on the entire building and the hardware inside. water damage to the electrical and data infrastructure was remediation at a cost of 2.4 mill. servers and workstations was done at a cost of 4.7 mill. damage to the building from the actual fire and smoke\water damage to offices on the second floor and misc collateral damage only cost 940k. their insurance paid all but 1mill of that bill.
so dont think your covered by basic casualty or property insurance on those things.

 

[GrayHair]

As far as epo panic switches at the exits is concerned those are an open invitation to costly mischief.

And, I might add, error. A data center had magnetic locks on each door with a red mushroom button to allow exit. An employee hit the halon-system button located one stud-bay further from the door. They put covers over the EPO and halon buttons, and finally allowed us to bring those openings up to code.