How street lights get power

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anbm

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New design - a community in residential area has several single story - duplex houses & condos, etc.
Street lights will be installed along all pedestrian walkways in the community. How are those
lights powered and billed? The developer will pay for the electric bill. The light is 208V.
Max. (3) or (5) 20A circuits are needed to serve all lights with a total of 800 feet +/-
circuit length. Thanks.
 
480sparky said:
Simple answer: Depends.

Sometimes they're metered, sometimes they're not and just calculated.
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Are the circuit feeds the light tapped off the nearest utility transformer secondary that serves the residential units...?
Or they are fed from a dedicated single phase pole mounted transformer?
 
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Usually they are leased through the poco. They power them off the nearest transformer, and individual lights have photocells. They just fuse each pole individually, no breaker panel or contactor. If a panel is involved, usually the HOA has a metered house panel that supplies power to the poles, and any entrance signage. If it’s a gated community, could also power the gate and cameras.
 
hillbilly1 said:
Usually they are leased through the poco. They power them off the nearest transformer, and individual lights have photocells. They just fuse each pole individually, no breaker panel or contactor. If a panel is involved, usually the HOA has a metered house panel that supplies power to the poles, and any entrance signage. If it’s a gated community, could also power the gate and cameras.
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Can 20A circuit/single phase tap off secondary of three phase utility xfmr which has higher amp. secondary feeder to serve other building? how to meter this 20A circuit?
 
anbm said:
Can 20A circuit/single phase tap off secondary of three phase utility xfmr which has higher amp. secondary feeder to serve other building? how to meter this 20A circuit?
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Utilities can, it’s usually a #2 or 4/0 AL feed looped through the poles. Unmetered, fused only at each pole. If it’s non-utility owned, meter and service is usually required.
 
When we supply street lights to a development we tap off the nearest transformer. Usually with #12 UF.
It’s one of the reasons we try to put a light near every transformer.
If it’s a long run, and I mean really long run, we may use #10 and once I’ve used #2.
Never would dream of 4/0 loops.

As far as billing, we bill the HOA or owner for all the lights.
We have divided up the lights and put a portion on all bills but every homeowner must agree to it and it had to be an HOA amendment.

We allocate a kWh to each light to deduct from our sales so our system losses numbers aren’t skewed any worse than they already are.

If they are customer lights, they come off the “house” meter that’s required for the building lighting.
 
Thanks, cannot imagine wire greater than #8 ca be terminated at the lights... because the light is rated for 20A... Am i missing something here???
 
The HOA I live in pays the utility a fixed amount per month for street lighting. Covers everything including electricity, repair and replacement.
Lights are fed from the same transformers that feed the homes.

If such an arrangement can be planned in your case, the utility will want to handle everything.
 
Hv&Lv said:
When we supply street lights to a development we tap off the nearest transformer. Usually with #12 UF.
It’s one of the reasons we try to put a light near every transformer.
If it’s a long run, and I mean really long run, we may use #10 and once I’ve used #2.
Never would dream of 4/0 loops.

As far as billing, we bill the HOA or owner for all the lights.
We have divided up the lights and put a portion on all bills but every homeowner must agree to it and it had to be an HOA amendment.

We allocate a kWh to each light to deduct from our sales so our system losses numbers aren’t skewed any worse than they already are.

If they are customer lights, they come off the “house” meter that’s required for the building lighting.
Click to expand...
Usually the 4/0 loops are for larger commercial parking lots, never seen the local poco’s around here run UF cable for anything.
 
Another configuration is a high-voltage, constant-current series string. I've seen a lot of them on airport runways where a whole lot of wire is needed to deliver relatively little power. If I recall correctly, a saturating-core transformer is used in each lamp base to keep the remainder of the string lighted when one bulb burns out. The high voltage and low current enable the use of a lot less copper.
 
drcampbell said:
Another configuration is a high-voltage, constant-current series string. I've seen a lot of them on airport runways where a whole lot of wire is needed to deliver relatively little power. If I recall correctly, a saturating-core transformer is used in each lamp base to keep the remainder of the string lighted when one bulb burns out. The high voltage and low current enable the use of a lot less copper.
Click to expand...

Some very old urban installations and parks have also used series string lighting. Maintenance is a pain.
Think of a series string Christmas light string with shunts on each bulb.
 
anbm said:
New design - a community in residential area has several single story - duplex houses & condos, etc.
Street lights will be installed along all pedestrian walkways in the community. How are those
lights powered and billed? The developer will pay for the electric bill. The light is 208V.
Max. (3) or (5) 20A circuits are needed to serve all lights with a total of 800 feet +/-
circuit length. Thanks.
Click to expand...

If the HOA is involved, they will charge me because I pay our HOA monthly for maintenance and other things, which includes street light charges.
 
anbm said:
New design - a community in residential area has several single story - duplex houses & condos, etc.
Street lights will be installed along all pedestrian walkways in the community. How are those
lights powered and billed? The developer will pay for the electric bill. The light is 208V.
Max. (3) or (5) 20A circuits are needed to serve all lights with a total of 800 feet +/-
circuit length. Thanks.
Click to expand...
PV, batteries & LED's
 
anbm said:
Thanks, cannot imagine wire greater than #8 ca be terminated at the lights... because the light is rated for 20A... Am i missing something here???
Click to expand...
With the poco, the light amps is not really the concern, they use oversized wire because they buy it in bulk, and if they don’t have a lot of them to to do, it doesn’t pay for them to have small wire in stock collecting dust. At least that’s the way it is around here.
 
anbm said:
Thanks, cannot imagine wire greater than #8 ca be terminated at the lights... because the light is rated for 20A... Am i missing something here???
Click to expand...

Why do you feel larger than #8 wouldn't be able to be terminated at each light?

How many lights are there? Individual aluminum light poles I assume?

-Hal
 
anbm said:
Thanks, cannot imagine wire greater than #8 ca be terminated at the lights... because the light is rated for 20A... Am i missing something here???
Click to expand...


Voltage drop and opening the breaker during a fault. A single #12 has a resistance of 2 ohms per 1000 feet, which would never trip the breaker at anything over that length leaving the pole energized based on chapter 9 table 9 of the NEC.
 
hillbilly1 said:
With the poco, the light amps is not really the concern, they use oversized wire because they buy it in bulk, and if they don’t have a lot of them to to do, it doesn’t pay for them to have small wire in stock collecting dust. At least that’s the way it is around here.
Click to expand...

Yup, in addition that you want current for a fault. :)
 
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