Information Technology Room: Article 645

[steve66]

I have learned the following from this forum:
1. If the requirements of 645.2 are met, the room can be considered an Information Technology room.
2. If the room meets #1 above, then the "easier" wiring methods allowed in article 645 can be used.

What I don't get: What wiring methods in are "easier". In other words, what do you gain by meeting the requirements of 645.2? Branch circuit conductors still have to be in a raceway. I don't see anything allowed in 645 that looks like it would be a violation even if it wasn't in a information technology room.

STeve
Steve

 

[ron]

Re: Information Technology Room: Article 645

Steve,
Excellent question.
Although minor, lets start with a clarification:
Any room you like can be called an "Information Technology Equipment Room". By the nature of the room name, does not require any particular code section to be invoked.
If you wish to use the leniencies "easier" permitted by 645, then you must comply with 645.2
It is a backward worded paragraph, and is optional.
Some of the leniencies include:
15' cords,
receptacles/cords below the raised floor and
don't have to secure in place cables and receptacles that are part of the IT equip.

I don't think in many cases that the liabilities assumed by compiling with 645.2 are worth some of the cost savings gained.

 

[dereckbc]

Re: Information Technology Room: Article 645

Steve, like Ron, I design a lot of data centers and Telco office design work. We avoid 645 where ever possible because of the EPO switch requirements. We only use it if the local AHJ insist.

Some companies like to use it because it is a lot easier for their technicians to run listed signal cables, and hide their mess. I use overhead cable racks for signal and DC power distribution. This requires the cables to be laced in place very neatly on cable racks and meet seismic requirements. However with 645 you can open the raised floor and slop in the cables any ole way you please.

From an electrician point of view, it allows some leniencies with receptacles and supplemental signal reference grid ground conductors (SRG). Since I specify bare SRG conductors, it nullifies any benefits of 645 except for receptacles and listed signal cables. Just my two-cents worth.

 

[steve66]

Re: Information Technology Room: Article 645

Thanks for the replies. Since I posted that question I have found 300.22(C) Wiring in Air handling spaces. That brings up another question.

If the raised floor space isn't used for air handling, can I omit the EPO, and still have cables and receptacles under the raised floor?

Steve

 

[ron]

Re: Information Technology Room: Article 645

If you comply with 300.22(C), and do not need the leniencies permitted by 645, then you do not need an EPO or any other requirement of 645.2 for that matter.

 

[ron]

Re: Information Technology Room: Article 645

One other big item that is permitted by 645 that I didn't mention, is that you can put non-plenum rated low voltage wire below the floor, air handling or not.
I don't recommend this to my clients, but it can be done.
Of course this is a big cost to consider.

 

[steve66]

Re: Information Technology Room: Article 645

Thanks for the info. Ron

Steve