Another NEC quiz - Flourescent lighting wiring

[rjgoebel]

This structure was built in 1960, keep in mind, so if anyone knows a great deal about how long the NEC has been around or on its standards way back when, feel free to chime in.

What was done is: A 277V flourescent light fixture has 2 other lights on the same branch controlled by one switch, and a whole seperate circuit branch running through it, with conduit on one side (4 wires) running in, and flexible conduit as one of the 2 conduits running out and solid steel conduit running out that connects the rest of the lights on that same branch.

Basically, it seems pointless to have those two seperate circuits running through the same light especially considering that they are coming from the same breaker branch as far as I can tell. However, I have seen much much worse out there in terms of wiring. What would the NEC have to say about this?

Jim Goebel,
Electrical Engineer
Mid-West Forensics, Inc.

 

[davidbeach]

If the luminaires are listed as raceway, no problems; if they are not listed as raceway then the other circuit(s) are not allowed to enter.

 

[advidana]

It's old and it may have not been installed that way when first built , it may have done later. Have the owner fix it.

 

[skiier]

The cct may have been used for night lighting perhaps?
It's been 45 yrs since the original install and lighting changes and modifications to switching may have occurred.
It was, and still is, common practise to use row mounted light fixtures as raceways for auxiliary lighting circuits within the same row.
Do you need to really fix anything?

 

[peebee]

Davidbeach is dead on. If the fixtures as listed as raceways then there's no problem, otherwise your installation is a violation.

How long has the NEC been around? Since 1899. There's a PDF of that first NEC revision available on mikeholt.com .

 

[resqcapt19]

410.32 Wiring Supplying Luminaires (Fixtures) Connected Together
Luminaires (fixtures) designed for end-to-end connection to form a continuous assembly, or luminaires (fixtures) connected together by recognized wiring methods, shall be permitted to contain the conductors of a 2-wire branch circuit, or one multiwire branch circuit, supplying the connected luminaires (fixtures) and need not be listed as a raceway. One additional 2-wire branch circuit separately supplying one or more of the connected luminaires (fixtures) shall also be permitted.

 

[HCBFlash]

I've thrown away most of my old code books, but the current NFPA 70.410.11, 410.22, 410.28, 410.31, 410.32, 410.33, 410.67 articles cover requirements that haven't been very much affected over the years.

...or at least compared to many, many others in our current "National Exception Catalog"!

The larger issues in maintaining or replacing your wiring aren't primarily covered directly by NPFA70. ALL municipalities or other AHJs have specific legal requirements. You need to know these, since you are bound by them. Your facility may have been in such an area or position that had little or no specific electrical requirements in the applicable building codes in 1960.

Some municipalities (like Chicago) have had thier own electrical codes predating the "NEC". Chicago's code was a higher standard than NEC, as well as simpler. (I haven't had dealings within that jurisdiction in several years tho)

The National Electrical Code Handbook would probably help you out somewhat.

Multiwire branch circuits, emergency lighting circuits, and "night lighting" may all be normally present wiring in some installations

..

Start each day off with a smile
,,, then you've at least that much out of the way!