Pole Lighting Wiring

[mshields]

Haven't done street lighting in a while. Looking for a sanity check.

I've got a 900 foot stretch of roadway with 30 pole lights (lantern type on 12 foot poles). I'm going to run two 240V circuits and pick up every other fixture on the two circuits. I plan to run #6's which more than compensates for any Voltage drop concerns.

Typically I don't run less than 2" conduit underground for anything. So that's the plan. I also don't see a need for handholes, opting instead to pull from pole base to pole base (is that a mistake? I certainly don't want to have a HH per fixture).

If I'm to run the 2 circuits through each pole base as is the plan, I can't see putting 2 2" conduits in the pole base. For 40% fill, I do need 1 1/4 inch.

That being the case, I'm thinking I should probably just go with the 1 1/4 across the board in lieu of 2 inch.

Anything wrong with my thinking on this? I appreciate your input?

Thanks,

Mike

 

[ActionDave]

If you made me run 2" for pole lights I would hate you forever and stalk you and show up at family events and do embarrassing things to you.

1 1/4" is a better choice IMO. Smaller diameter means smaller radius for bends, easier to get in the center of the pole base, just a more pleasant install overall.

 

[petersonra]

why not let the EC decide those kind of details. As long as it meets code, why worry about such things.

 

[mshields]

OK

OK

I surrender

1 1/4 if only to avoid being stalked

 

[texie]

I would consider putting a handhole near each pole base and just run a 3/4 or 1" to each pole with #12 or 10. If 1 1/4 gives you 40% fill I'd run 2" handhole to handhole. There is no way I would consider 2, 2" directly into a typical pole base of this type. The other advantage of handholes comes when a car hits the pole.

 

[Fulthrotl]

I surrender

1 1/4 if only to avoid being stalked

he will, too. he's vindictive that way.

i've used 2" for poles only when i was wanting
them to pull power in later possibly.

 

[jumper]

he will, too. he's vindictive that way.

I think it is the thin mountain air, makes him a bit loopy.

 

[Cow]

How far apart are the pole bases?

 

[jumper]

How far apart are the pole bases?

OP said 30 poles over 900’, so maybe ~30’ I would guess depending where pole#1 is in the run.

 

[JFletcher]

Unless I'm looking at the wrong or misreading the charts, why do you even need 1.25" for #6? If you're using 240V circuits, you need 5 wires: 4 hots and a ground, yes? You can get 7 #6s in a 1" conduit, which would cover two neutrals as well for MWBC/120V applications (Receptacles anywhere on/near the lights?).

eta: I see schedule 40/80 in 1" has a 6/5 fill limit for #6, which is still plenty for just 240V applications, tho 1.25" would be needed if you're pulling noodles too.

http://www.elliottelectric.com/Stat.../ElectricalTables/Conduit_Fill_Table_PVC.aspx

 

[rlundsrud]

What is the current draw for each pole?

 

[petersonra]

Unless I'm looking at the wrong or misreading the charts, why do you even need 1.25" for #6? If you're using 240V circuits, you need 5 wires: 4 hots and a ground, yes? You can get 7 #6s in a 1" conduit, which would cover two neutrals as well for MWBC/120V applications (Receptacles anywhere on/near the lights?).

eta: I see schedule 40/80 in 1" has a 6/5 fill limit for #6, which is still plenty for just 240V applications, tho 1.25" would be needed if you're pulling noodles too.

http://www.elliottelectric.com/Stat.../ElectricalTables/Conduit_Fill_Table_PVC.aspx

you really want to pull (5) #6 wires through 1" PVC?

 

[JFletcher]

you really want to pull (5) #6 wires through 1" PVC?

Not that hard. One can pull 4 coax or 6 cat5e thru 3/4" ENT up to 100' and 4 bends w/o blowing the 25lb pull force limit. That's with a copious amount of Clear Glide tho. #6 and coax have an OD right at a 1/4".

~~~~~~~~~~~~~~~~

Mike wrote:

"I plan to run #6's which more than compensates for any Voltage drop concerns."

Yes it does, perhaps too much. If you're running 20A circuits, you can load to 16A continuous. The midpoint of your run would be 450', and 8A load there if maxxed out. #8 could be used. You could also use #12 for the farthest out lights with the least load, then #10, and #8 (or 6) to finish. That would allow using 1/2" PVC a ways, then 3/4", then 1" (or 1.25") closer in.

Using 1.25" conduit and #6 throughout will be quite a bit more in material cost than using differential sized wire and conduit. Just using 1.25" conduit over 1" is over $200 with 900' of conduit and 60 90* sweeps to get into and out of each of the 30 light poles. 500' spools of #6 are ~ 230$; #12 is roughly a quarter that. Considering that at 900' and just 5 conductors you'll need over 4500' of #6, or 10 spools, using #6 all the way will cost about a $1000 more in wire cost vs staggering the wire. Sounds like $1200+ more in my pocket...

Labor for pulling and terminating the wire is roughly the same either way, as is your conduit assembly and trenching cost.

eta: If using schedule 40 PVC, one can get 5 #8s in 3/4" PVC, which is half of what 1.25" costs. Food for thought...