Cable Tray-Emergency Feeder

[augie47]

I have an industrial plant where there are many 15kv cables in cable tray serving subs within the plant. A separate 15kv utility supply has been added for emergency power and the emergency power 15kv cables have been placed in the same cable tray as normal power separated by about 24". Is this a violation.
I know the feeders can't share the same raceway but what about cable tray ?

 

[jdsmith]

Is this an ordinary type TC tray cable or a CLX type corrugated armored tray cable, type MC or MC-HL? I'll take a look at the codebook in the morning.

 

[RUWired]

How do you define entirely independent? IMO a physical seperation via a metal barrier would be required. Being in the "same" support system is not being independent.

(B) Wiring. Wiring of two or more emergency circuits supplied from the same source shall be permitted in the same raceway, cable, box, or cabinet. Wiring from an emergency source or emergency source distribution overcurrent protection to emergency loads shall be kept entirely independent of all other wiring and equipment, unless otherwise permitted in (1) through (5):
(1) Wiring from the normal power source located in transfer equipment enclosures
(2) Wiring supplied from two sources in exit or emergency luminaires
(3) Wiring from two sources in a common junction box, attached to exit or emergency luminaires
(4) Wiring within a common junction box attached to unit equipment, containing only the branch circuit supplying the unit equipment and the emergency circuit supplied by the unit equipment

 

[Volta]

I would tend to agree with RUWired, but first, is this a facility that is legally required to have an emergency system to supply power and lighting essential for safety to human life 700.1?

 

[augie47]

The decision was as RU wired suggests (barrier) but there was discussion and I wanted opinions.
I do not yet have the input on the "requirement" but as there are no
battery pak lights, etc I am assuming this alternate source is the accepted and required emergency system. On this particular install, all those decisions are handled way above my grade,

 

[steve66]

How do you define entirely independent? IMO a physical seperation via a metal barrier would be required. Being in the "same" support system is not being independent.

If you are going to say the support system has to be independent, doesn't that imply that 2 separate conduits on the same unistrut hanger would also be a violation?

Are we talking about a solid, enclosed cable tray, or a ladder type tray?

I like the divider, and i would spec. one if it were my project, but I'm not sure it would be required per Code if the feeders are ran in another wiring method.

Steve

 

[RB1]

I don't think "entirely independent" as used in the context of 700.9(B) is applicable for separate raceways or cables utilizing the same support system. I do think that the performance objectives of 700.12 apply. The paragraph that provides: "Equipment shall be designed and located so as to minimize the hazards that might cause complete failure do to flooding, fires, ice, and vandalism." would prohibit the type of installation that you have described. In my opinion the "complete failure" referenced in the paragraph would be the simultaneous loss of both supply sources. In this installation a complete failure would occur if the section of cable tray supporting feeders from both sources was exposed to fire.