Power and data share raceway

Q

The project that I am working on deals with an outside lighting pole and a security camera attached to it at our SSA stores. Initially, the plan was to use the pole as a raceway for the power to the lighting and for the wiring of the camera. However, this is a Code violation of NEC 410-15, which states: “Low-voltage and limited-energy system conductors and cables for cameras, speakers, etc., cannot be installed within the same raceway as the lighting fixture power conductors.”

To correct this problem, the NEC suggested running the camera connections in a flexible raceway. How can you support this flexible metal conduit inside the raceway (inside the pole)? Is there anything in the NEC that states how the flexible metal conduit in a vertical raceway has to be supported? Does any vertical conduit in raceway less than 100 ft long need only to be secured at the top of the vertical raceway or as close to the top as possible? (This is similar to NEC Code 300-19 “Supporting Conductors in Vertical Raceways.”)

A

I see more than one way to approach your question under the NEC. But a few points should be clarified first. One, you are apparently referencing the 1999 NEC, but I will refer to the 2002. These two editions of the NEC do not differ significantly on this question except for the form of the reference and the article numbers covering the wiring methods. Two, the metal pole is not a raceway as such. Section 410.15(B) permits the pole to be used as a raceway for the purpose of supply conductors to the pole luminaire, but it is not a raceway for other purposes. Three, 410.15 does not mention limited energy circuits. The requirements for separation between limited energy circuits and power/lighting circuits are found in the applicable articles of Chapter 7 or 8. The wiring for a camera is likely covered by Articles 725 and/or 820.

Because the pole is not a raceway as defined in Article 100, I would look for separation requirements in 725.55(J) and 820.52(A)(2), both titled “Other Applications.” These sections are essentially the same and allow separations to be maintained by enclosing either the power supply conductors or the limited energy conductors in a raceway. (Another option might be to put the supply conductors in Type MC or AC cable, which might solve some installation problems, because the limited energy cables don't require raceways.

If you choose flexible metal conduit, 348.30(A), Exception No. 1 exempts the FMC from the normal support requirements where it is fished, as it would be in your poles. (According to statements in previous Code changes and the current definition of a structure, the poles are structures.) Similar exceptions are provided for LFMC and LFNC and also for Types MC and AC cable. You will have to secure the raceway at the access points, that is, at the top and bottom. The method you would use to secure the fished raceways depends on how the cameras are mounted on the poles.

Since the vertical support requirements apply to the conductors supplying the luminaires, as stated in 410.15(B)(6), these conductors will require support based on Table 300.19. You did not say how tall your poles are, but in most cases, with conductors of 8 AWG or smaller and poles less than 100 ft tall, no special fittings are required and the conductors require support only as necessary to protect the conductors from damage. The requirements of Section 300.19 do not apply to Class 2 or CATV conductors according to Sections 90.3 and 725.3, but if you want the circuits to be reliable, you will, of course, support the limited energy cables in a way that will avoid damage to the cables. Noel Williams

Safety code for elevators and escalators

Q

We have just received a copy of the latest Safety Code for Elevators and Escalators. They have completely re-organized this book, which has made a complicated manual even worse.

I have two National Electrical Code related questions:

  1. The new version calls for the installation of lighting in the pit and elevator equipment room (as in previous editions). But there is no mention of the requirement for a convenience receptacle. Am I supposed to assume that the NEC is now the governing body for this requirement?

  2. In the NEC Article 620.22, 620.23 and 620.24 all talk about the requirement for a “Separate Branch Circuit.” Does this mean that each location (car lighting, elevator machine room and elevator pit) all need separate circuits for a total of three? Or can any or all be combined into one or two separate circuits?

A

I do not have a copy of the latest elevator code. The 2002 NEC still refers to the 1996 version of ANSI/ASME A17.1 in Article 620. In all of the jurisdictions where I have worked, electricians and electrical contractors are not permitted to work on elevators except for providing power to the elevator room and installing the machine room and pit lighting and receptacles. There are often separate inspection agencies as well.

If the elevator code has deleted the requirements for receptacles in pits and machine spaces, and I'm not sure that it has, then I suppose the NEC is the more stringent requirement in that respect and would still apply.

The rules in Sections 620.22, 620.23 and 620.24 each call for separate branch circuits. Additional separate circuits may be required by 620.25.

According to these rules, at least three branch circuits are required. One is required for elevator car lighting and receptacles, one for machine/control room lighting and receptacles and one for hoistway pit lighting and receptacles. (GFCI requirements and prohibitions are found in Sections 620.23, 620.24 and 620.85.)

Actually, car lights and car heating/air conditioning require separate branch-circuits for each car. The branch-circuit overcurrent devices for these circuits and the circuits covered by 620.25 must be in the machine/control space. Thus, an installation that includes two cars may require as many as six separate circuits: two for car lighting, two for car air-conditioning and heating, and one each for the pits and machine/control space. The branch circuit overcurrent devices for four of these circuits have to be in the machine/control space. (This assumes that each car has air conditioning or heating and no other utilization equipment — many cars have none of these.) The requirements for separate circuits and the prohibitions for installing GFCIs in lighting circuits are intended to increase the reliability and independence of each individual circuit and load.

The requirement for overcurrent devices to be located in the machine/control space does not necessarily mandate a panelboard, as fusible switches or separately enclosed circuit breakers supplied and tapped from a feeder could be used. Also, according to the NEC, multiwire branch circuits could be used for these loads because multiwire branch circuits may be considered either as one circuit or as multiple circuits according to the language of Section 210.4. (In some cases a multiwire branch circuit may be treated as one circuit in one location and multiple circuits in another location. See 225.30 for an example.)
Noel Williams

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