Conduits required for DC power?

[kbross]

Some datacenters are looking at using DC rather than AC power distribution to minimize power conversion losses and increase overall efficiency. People are looking at telecom-style -48VDC power as well as 400VDC power for these applications. These are not low power devices; we talking 1-5kW (or more) typical per power feed.

Any feedback on whether these power feeds would need to be in conduit, or could open raceways be used, like telecom carriers typically use? Does the answer to this change with 400VDC vs. -48VDC?

Note: these datacenters would be operated by companies *not* regulated as utilities.

Any feedback would be appreciated.

 

[jim dungar]

The NEC applies to both AC and DC. Unless your application is covered under 725, 760 or 800, you always need to follow articles 300, 400, and in this case 645.

 

[petersonra]

Any feedback on whether these power feeds would need to be in conduit, or could open raceways be used, like telecom carriers typically use? Does the answer to this change with 400VDC vs. -48VDC?

Note: these datacenters would be operated by companies *not* regulated as utilities.

Any feedback would be appreciated.

The voltage level does not matter.

In some respects, it depends on what you mean by "open raceway", and just where you would install such a thing.

Also, keep in mind that for most purposes, the NEC stops at the connection point to a piece of equipment. How it is wired past that point may not be covered by the NEC.

Who owns/operates the equipment may or may not have a bearing on the question. Some jurisdictions require equipment on customer premises to meet all the codes, even if it is utilty owned, often with some big exceptions though (like no access except to the utility).

 

[kbross]

Clarification on opens

Clarification on opens

Bob/Jim,

Thanks for the replies. I was referring to the approach typically used in telecom central offices for routing cables; the attached image shows one example of the power cable raceways I am talking about.

If the datacenter is operated by someone who is not considered a utility (or by a company for their own internal usage), I'm wondering if they'd be able to use the same sorts of cabling practices.

I haven't had a chance to look up the NEC references Jim mentioned, but it's sounding like the telecom style of power cable routing may not be allowed in non-utility datacenters, even if they tightly restrict who has access to the facility.

Thanks,
Kevin

 

[jim dungar]

Your picture is of cable tray. This appears to be is an acceptable wiring method for your cables.

The NEC exception for utilities does not blindly exempt all of their buildings. For example, an electric utility's buildings must meet NEC requirements, however their generator equipment and distribution sytem does not.

 

[petersonra]

Your picture is of cable tray. This appears to be is an acceptable wiring method for your cables.

The NEC exception for utilities does not blindly exempt all of their buildings. For example, an electric utility's buildings must meet NEC requirements, however their generator equipment and distribution sytem does not.

I agree. This is a normal wiring method used in many installations for wiring of lots of different things. One might be inclined to think an architect would know about cable tray.