Grounded Conductor Identification - DC Circuits

[ron]

Non-utility application with a -48V DC plant to serve computer equipment, which means we need to comply with the NEC. -48V means the positive terminal is intentionally grounded.

I am planning to have the grounded conductor identified as white or gray as required by 200.6

Anyone see a way around the 200.6 color code for the grounded conductor?

I thought maybe because it was 48V, it might be exempt, but the scope for Article 200 (200.1) seems to still require compliance for this application. I would say this is part of the premises wiring identified in the scope.

 

[texie]

Non-utility application with a -48V DC plant to serve computer equipment, which means we need to comply with the NEC. -48V means the positive terminal is intentionally grounded.

I am planning to have the grounded conductor identified as white or gray as required by 200.6

Anyone see a way around the 200.6 color code for the grounded conductor?

I thought maybe because it was 48V, it might be exempt, but the scope for Article 200 (200.1) seems to still require compliance for this application. I would say this is part of the premises wiring identified in the scope.

Not sure, as I don't have any code books handy. But I seem to recall that the 2014 NEC has made some clarification to this.
Maybe someone else will chime in.

 

[don_resqcapt19]

I don't see anything that there is a voltage level on the rule is 200.6, but 200.7(B) implies that there is one. There clearly is with the rules in 210.5(C)(2) and 215,12(C)(2) in the 2014 code, that cover the identification of DC system conductors.

 

[ron]

I am interested in the changes for 2014, but for this project in NYS, we are 2008.

 

[ron]

I don't see anything that there is a voltage level on the rule is 200.6, but 200.7(B) implies that there is one. There clearly is with the rules in 210.5(C)(2) and 215,12(C)(2) in the 2014 code, that cover the identification of DC system conductors.

200.7(B) does identify voltage, but directed when the white / gray conductor is required to be grounded. The client has determined it will be grounded, now we are discussing conductor insulation color

 

[dereckbc]

Ron for the few times I had to use color code on 48 volt plants is I used gray. We used gray for everything on the DC side. It was the black that was hard to source in the insulation type we used. I am sure you have seen it as it has a RHH/RHW-2, Flex, with a cotton fabric cover.

Another one we used a lot and comes in various colors is made Cobra which uses a smokeless XLP insulation RHH/RHW-LS2.

Check out Cobra website as they have a lot of the special cables used in Telco and Data especially the 750 and 500 MCM in various colors. I use a lot of what they call Telco Flex Class I strand

 

[ron]

Dereck,

In addition, the conductor insulation needs to be tray rated (being installed in tray), which makes it even tougher to source.

Code compliance for a system that typically is a "utility" system, is interesting.

 

[dereckbc]

Dereck,

In addition, the conductor insulation needs to be tray rated (being installed in tray), which makes it even tougher to source.

Code compliance for a system that typically is a "utility" system, is interesting.

Ron I have done a lot of large plants in High Rise buildings for Telco and being a utility did not mater since they are public buildings. A few areas like King of Prussia did not allow us to use cable rack with RHH/RHW so in those cases we installed Raised Floor (non Plenum) and ran the cables under the raised floor with AC circuits in Raceway. Not talking a few cables, but at least 100 runs of 750/500 MCM depending on length to the power distribution frames (PDF) on the equipment floor.

Funny thing is they had no problem with running #6 AWG DC over head in cable racks from the PDF to equipment frames, only cables that had AC circuits on the trays had to be TC rated and we segregated them from DC and signal cables. I am kind of cluesless as of why as all our DC power cables use the cotton fabric covering and sewn on to the cable racks and break-offs into the frames. No way that stuff is gong to move. What is even stranger is they had no problem when Nortel or Lucent coming with with the switches that have integrated cable rack racks and running power in them on top.

Biggest issue I have is weight. Some of the large sites with 10,000 AMP -48 Plants will have 24-inch cable racks piled up 6 inches of 750 MCM leaving the battery room.

 

[dereckbc]

Dereck,

In addition, the conductor insulation needs to be tray rated (being installed in tray),

Use Cable Rack instead of tray.