Lamp Posts

[frank_n]

I am bidding on a job where the owner wants 9 lamp posts. There will be 9 32 x 32 x 42(H) brick posts and each post will have a 180-watt fixture. The length of the circuit will be no more than 200 feet.

I plan on running one 20-amp circuit with #6 THWN in a 1" PVC. The lights will be controlled by a photo-electric eye.

I know I am going to have to stub up from the ground with the PVC, but I am not sure how to make the connection from the PVC to the Light Fixture. I know I have to install a Pier Mount.

Are the wires connected with conduit, or just hang free between the PVC and the fixture?

Frank

[iwire]

You are required to provide a box for the fixture.


You could use something like this

9" Post/Deck Mount Support for Outdoor Light Fixtures (http://www.arlcatalog.com/Weatherproof/9%20Post%20Deck%20Mount%20Support%20for%20Outdoor% 20Light%20Fixtures.htm)


Keep in mind that if you run 6 AWG for your circuit conductors you must run a 6 AWG EGC per 250.122(B).

For the wattage and length I would use 10 AWG.

[badabing]

You are required to provide a box for the fixture.


You could use something like this

9" Post/Deck Mount Support for Outdoor Light Fixtures (http://www.arlcatalog.com/Weatherproof/9%20Post%20Deck%20Mount%20Support%20for%20Outdoor% 20Light%20Fixtures.htm)


Eww... really, you'd use that on top of a brick post??

[ceb58]

Not sure what I would use to mount the light just be sure the photo cell is rated to handle the amps

[frank_n]

You are required to provide a box for the fixture.


You could use something like this

9" Post/Deck Mount Support for Outdoor Light Fixtures (http://www.arlcatalog.com/Weatherproof/9%20Post%20Deck%20Mount%20Support%20for%20Outdoor% 20Light%20Fixtures.htm)


Keep in mind that if you run 6 AWG for your circuit conductors you must run a 6 AWG EGC per 250.122(B).

For the wattage and length I would use 10 AWG.

I have never seen something like that on top of a brick post before.

#10 THWN has a voltage drop of 5.4%
#8 THWN has a voltage drop of 3.5%
#6 THWN has a voltage drop of 2.2%

Since 210.19(A)(1) FPN No.4 says the max voltage drop of the branch circuit should not exceed 3% I planned on using #6. FPN are part of the Code, not suggestions (am I right?).

Thanks for catching my mistake on 250.122(B)

Frank

[frank_n]

Not sure what I would use to mount the light just be sure the photo cell is rated to handle the amps

I'm planning on a Tork 2000 watt photo-cell

[LarryFine]

You can always stagger the wire sizes: #6 to the first two (or three), #8 to the next two, #10 to the next two, and #12 to the last three (or two.)

[220/221]

IMO, the wire size and conduit is way over killed.

3/4" and 10's will do it.


Stub up into the center of the piers and terminate in a 4/0 box mounted flush with the top.

I'd also use a contactor and keep the load off the pcell.

180 watts is over kill too. 3, 60 watt incandescants? Use 3, 13W cfl's. It will save a lot of maintenance and energy over the years.

[Dolfan]

IMO, the wire size and conduit is way over killed.

3/4" and 10's will do it.


Stub up into the center of the piers and terminate in a 4/0 box mounted flush with the top.

I'd also use a contactor and keep the load off the pcell.

180 watts is over kill too. 3, 60 watt incandescants? Use 3, 13W cfl's. It will save a lot of maintenance and energy over the years.

Glenn Beck would not agree on the cfl's

[frank_n]

IMO, the wire size and conduit is way over killed.

3/4" and 10's will do it.


What about the Voltage Drop?

180 watts is over kill too. 3, 60 watt incandescants? Use 3, 13W cfl's. It will save a lot of maintenance and energy over the years.


If I use the cfl's I can use #12's. :D

I'm wondering how many people here think I should ignore the Voltage Drop. Isn't the FPN a requirement and not a suggestion? How will I ever pass inspection if it is a requirement?

Frank

[kelley]

Take a look at this option.

http://www.1stoplighting.com/ProductSheet.aspx?pid=23086

[frank_n]

Glenn Beck would not agree on the cfl's

Glenn Beck has a good point, however many people out there want the CFL's. It's usually the same people with the 4,000 square ft. house. :D

[MrMilbank]

spec it for cfls and someone puts in an incandescent a few years from now. when they got problems you dont wanna hear about it. i would would stagger the wire sizes each within the 3% tolerance rated at the max fixture wattage.

and does that pier mount need to be UL listed/labeled??

[JES2727]

Frank,
Take a look at 90.5(C) regarding the Fine Print Notes.
I agree that #6's are overkill for this application.

[mark32]

I like 220/221's suggestion about using a contactor in conjunction with the photocell, I must ask what a 4/0 box is though. Also, never having done such an install, I can imagine stubbing pvc up into a pier mount but I then cannot imagine connecting that to a box. I've seen pier mounts but I can't see fitting a box into one.

[fondini]

Glen Beck rocks!

[LarryFine]

Glen Beck rocks!
What about them? :-?

[frank_n]

I like 220/221's suggestion about using a contactor in conjunction with the photocell, I must ask what a 4/0 box is though. Also, never having done such an install, I can imagine stubbing pvc up into a pier mount but I then cannot imagine connecting that to a box. I've seen pier mounts but I can't see fitting a box into one.

A 4/0 box is a round 4 inch box. I don't think the Pier Mount would mount to the box, but mount over it.

Frank

[K8MHZ]

What about the Voltage Drop?



If I use the cfl's I can use #12's. :D

I'm wondering how many people here think I should ignore the Voltage Drop. Isn't the FPN a requirement and not a suggestion? How will I ever pass inspection if it is a requirement?

Frank

Just the oppostite:

7. Fine Print Note (FPN). A Fine Print Note contains explanatory material intended to clarify a rule or give assistance, but it isn't a Code requirement.


That being said, I always try to maintain a 3 percent or less drop, 5 percent being max. On line calculators make the design easy. Trust me, years down the road, the customers will be glad you did the extra work.

[celtic]

In regards to the question of FPNs....they ARE "code" here in NJ:


*** THIS FILE INCLUDES ALL REGULATIONS ADOPTED AND PUBLISHED THROUGH THE ***
*** NEW JERSEY REGISTER, VOL. 41, NO. 7, APRIL 6, 2009 ***

TITLE 5. COMMUNITY AFFAIRS
CHAPTER 23. UNIFORM CONSTRUCTION CODE
SUBCHAPTER 3. SUBCODES
N.J.A.C. 5:23-3.16 (2009)
5:23-3.16 Electrical subcode
(a) Rules concerning the subcode adopted are as follows:
1. Pursuant to authority of P.L. 1975, c. 217, as modified by P.L. 1996, c. 53, the Commissioner hereby adopts the model code of the National Fire Protection Association, known as "The National Electrical Code 2008" as the electrical subcode for New Jersey.
i. Copies of this code may be obtained from the sponsors at NFPA, One Batterymarch Park, Quincy, Massachusetts 02269.
2. The National Electrical Code 2008 may be known and cited as "the electrical subcode."
i. Codes and standards referenced in the Fine Print Notes (FPNs) of the electrical subcode (NEC 2008) shall be considered adopted by reference to the extent prescribed by each related section. These codes and standards also are printed in DCA Bulletin #09-1, which contains a list of adopted codes and standards that are applicable to the enforcement of the electrical subcode.
http://www.state.nj.us/dca/codes/code_assist_internet/barrier_free/pdf/sub_3_tech_amend_4_20_091.pdf

[wireguru]

you could run #12, and put 130v lamps on the closer posts, and 120v lamps on the ones further out :D

[Dirt merchant]

You can always stagger the wire sizes: #6 to the first two (or three), #8 to the next two, #10 to the next two, and #12 to the last three (or two.)

I have thought about this before--any thoughts, can this be done by code?

[LarryFine]

I have thought about this before--any thoughts, can this be done by code?Yes, as long as your OCP protects the smallest wire.

[Dirt merchant]

Yes, as long as your OCP protects the smallest wire.

Just to be clear, As long as the voltage drop doesn't go below 3% at any given point of a run, it is acceptable to vary the conductor size? I am newly Licensed and am not looking for problems with inspectors. I get it with the OCPD being 20A. Any place in the codebook that would violate this would be nice to see now before I consider to do this. I have looked on my own, but can't find anything.

[Dirt merchant]

I generally only think about this when runs are over 1,000 feet long.

[mark32]

A 4/0 box is a round 4 inch box. I don't think the Pier Mount would mount to the box, but mount over it.

Frank


Hi Frank, if I read you correctly, the four inch round would be embedded in the post yes? If so, I imagine once the connections are made they'd still be floating in the air between the fixture and the box, not sure what the purpose of the box would be in this case. Am I crazy?

[220/221]

1. Bring the mason some doughnuts/coffee.

2. Before the column footings are poured, trench and install conduit stubbing up appx 42" above grade in the center of the block/brick columns.

3. When the columns are started but not complete (in order to get an ACCURATE measurement), install your jboxes, face up, landing flush with the finished top. (measure up from whatever coarse they are at). Be sure and duct tape your boxes well. Masons love to dump mortar into our conduits.

4.The masons will install the cap layer around your jbox and you can mount your fixtures to the JB or to the column cap.


I generally like to pull wire before everything is backfilled/complete (the just in case factor) but, if there are no hidden issues, it will be easier to pull wire after the columns are set. If you DO pre pull wire, install blank covers on the jb's to keep the wies out of the masons way and to keep mortar out of the components.



If the fixture have a big base with lots of make up room, you could just stub the conduits up, cut them off flush and use the fixture base for wiring/make up. Does code require a jb in this case? I don't know.