Traffic Signal Poles as Raceways

Status
Not open for further replies.
J

jadie

Member
I do design for roadway lighting and traffic signal installations.

It has come to my attention that our standard practice (using grounded signal poles with a handhole as a raceway for traffic signal, pedestrian signal, pedestrian pushbutton, and vehicle loop detector wiring) may not meet code.

Article 410.15(B) states in part that "Metal poles shall be permitted to be used to support luminaires (light fixtures) and as a raceway to enclose supply conductors" but, could this be interpreted to include traffic signal items also?

If not (and I'm thinking not), are there other articles where this could be construed as meeting code?
 
Re: Traffic Signal Poles as Raceways

I don't see why traffic light poles wouldn't fit into 410.15. If you have a 2 x 4 handhole, I think the poles are OK as a raceway.

Steve
 
Re: Traffic Signal Poles as Raceways

They're not traffic light poles but poles that hold the messenger that hold the traffic signals. I guess one could technically call a traffic signal a 'light' but what about the wiring for the 'non-light' items? Am I still OK with running everything (same voltage) in the same pole?
 
Re: Traffic Signal Poles as Raceways

I work for the NJDOT on traffic lights etc. we run everything in the same conduits. The wiring for the loop det. are of the same voltage rating as the power, and the same for the peds. Besides its all of the same system ran of a common controller
 
Re: Traffic Signal Poles as Raceways

I am the author of the International Municipal Signal Association (IMSA) Journal Code Corner article. Traffic signal posts and mast arms would be considered a raceway per 410.15 (B) and seperation is required between "low voltage" circuits such as pedistrian push buttons, opticom, and power circuits such as signal lamps and lighting. The traffic signal industry essentially ignors many parts of the NEC.
At the IMSA National Convention a few weeks ago in Denver, there was a manufacturer who has installed video cameras in a signal head. I asked how the video signal gets back to the controller. " via a cat 5 cable" was the answer. Of course this is inside the pole, which is a raceway. If this was done in a building, it would be a violation.

410.15(B) states in part that "Metal poles shall be permitted to be used to support luminaires (light fixtures) and as a raceway to enclose supply conductors was added to the 1999 NEC to clarify that seperation is required in lighting poles etc, which would include traffic signal poles, mast arms and strain poles.

However in Washington State, we have a state adminstrative code that allows traffic signal installations to follow other standards and the mixing of low voltage and power in a pole is allowed.

Of of the problems with the traffic signal equipment and industry is the cables are not listed and the signal controllers, power supplies etc are not listed.
 
Re: Traffic Signal Poles as Raceways

Originally posted by jadie:
They're not traffic light poles but poles that hold the messenger that hold the traffic signals. I guess one could technically call a traffic signal a 'light' but what about the wiring for the 'non-light' items? Am I still OK with running everything (same voltage) in the same pole?
Click to expand...
It is a NEC violation. Most AHJ's dont see this. Some agencies do their own inspection. It can't be done anywhere else. but it is the standard practice for traffic signal installations. The issue is if the insulation was to break down or be damage 120, 240 or 277 volts could be applied to a loop detector or logic input to a controller and cause a fire or shock. And there is the issue of inductive noise.
 
Re: Traffic Signal Poles as Raceways

Originally posted by tom baker:
At the IMSA National Convention a few weeks ago in Denver, there was a manufacturer who has installed video cameras in a signal head. I asked how the video signal gets back to the controller. " via a cat 5 cable" was the answer. Of course this is inside the pole, which is a raceway. If this was done in a building, it would be a violation.
Click to expand...
Originally posted by tom baker:
It is a NEC violation.
Click to expand...
Tom,

Have you contradicted yourself or am I reading this incorrectly? My reference to wiring for 'non-light' items was meant to be in reference to pushbuttons and loop wire (of the same voltage as the signal heads as mentioned by ken987). Your comment regarding the pole as a raceway is what's throwing me. Is a traffic signal pole a raceway and, if so, where does it state so in the NEC?
 
Re: Traffic Signal Poles as Raceways

Here:
Article 410.15(B) states in part that "Metal poles shall be permitted to be used to support luminaires (light fixtures) and as a raceway to enclose supply conductors" but, could this be interpreted to include traffic signal items also?

We need to step back and take a look at the intent of the NEC. The intent is separation is required.You won't find the term "traffic signal pole" in the NEC. And if a traffic signal pole has a luminare on it then it must be metal pole supporing luminaires. And the argument could be made that a traffic signal head is a luminare, it does meet the art 100 definition for a luminare.

Now as far as separation for pushbuttons and loop wire, it does not mater what the insulation of the conductors are, NEC section 725.54 requires separation.

Tom Baker
IMSA Level II Traffic Signal Technician
IMSA Level I Roadway Lighting
IMSA IES Committe Chair
 
Re: Traffic Signal Poles as Raceways

In a issue such as this, the best approach would be to discuss with the AHJ. And some state agencies do there own inspection so its not a issue. Separation is required, and most traffic signal installations do not comply.
 
Re: Traffic Signal Poles as Raceways

Hey tom find me a pole that provides this separation, I may have not designed any intersections but I've put a lot together. Have yet to see any pole with any provisions for separation. I'm really no code expert, but I'm studing for my electrical license and was also wondering about 725.55 (D) my arugment really is that the loops, peds, veh detectors are really part of the same system. It's not like network cabling run next to power, say in a building. It's all of the same system. Its just like the ac in your house needs its signal the traffic controller needs its too.
 
Re: Traffic Signal Poles as Raceways

ken,
Its just like the ac in your house needs its signal the traffic controller needs its too.
Click to expand...
The code does not permit the air conditioner "signal wiring" to be in the same raceway or cable with the power wiring for that same air conditioner.
Don
 
Re: Traffic Signal Poles as Raceways

if you were to install a seperate raceway inside the pole, and a j-box on the outside, would this satisfy the separation requirements? I've noticed on some new prints that call for cameras mounted on parking lot poles, they have a separate conduit entrance to the pole base, then convert to liquidtight inside the pole, and run the liquidtight up the pole to a j-box where the camera is mounted.
 
Re: Traffic Signal Poles as Raceways

There are no poles that I know of that provide seperation that I know of. It can be done in the field with ENT sleeved inside the pole.

"loops, peds, veh detectors are really part of the same system" Not really. all of these devices have individual detectors, all run from the controller. Ok even if they are part of the same system, there are still signal heads and lighting on the poles, and those are 120 or 240 volts.

The separation issue is mostly ignored by traffic signal folks.

And you may be interested to know, IMSA 19-1 signal cable is a five conductor cable,
White-neutral
White/black stripe-spare
Red-red lamp
Yellow-yellow lamp
<and>
Green-green lamp

There is a UL listing for TS cable, with two manufacturers, but no one makes it as there is no one asking for it.
 
Re: Traffic Signal Poles as Raceways

I know of these cables, the New Jersey DOT uses them. They are not listed or have any UL approval. We use a 2, 5, 10 and 14 cond cables, which would bring me to 725.55(J) other applications, I think that because all the class 2&3 are run in these cables which are nonmetallic sheathed, and all the power conductors are run in these cables which are nonmetallic sheathed. That 725.55(J) would apply, correct me if im wrong. I agree with you on the fact that this industry is largly unregulated, other than the NTCIP, which dictates the operation of the controllers. I have been working with the state for 10 months and have tried making sense of most of the things they do. Like you mentioned it really comes down to the local agency is usually acts as it own AHJ so they see the installation as legal.
 
Status
Not open for further replies.
Top