How do I determine my electrical needs?
April 26, 2018 1:52 PM Subscribe
I’m considering converting shipping containers into a plant nursery and I’m trying to determine my electrical needs. Containers are located very near a utility pole with a transformer and the property owner has says the local utility can bring power to the containers quickly and easily once we let them know our power needs.
So, how do I determine my power needs? I am looking at having approximately eight 1,000 watt lights, one 10,000 BTU air conditioner, and 36 50-watt fluorescent lights, 3 or 4 exhaust fans, and enough juice to power a water pump. If the load is too high, I might want to consider LED lights. And what about the impact of adding additional containers?
Do I have to have an electrician determine this? Everything would be installed by a licensed electrician and would be done to code. I need this info before I can get an estimate from the local utility.
So, how do I determine my power needs? I am looking at having approximately eight 1,000 watt lights, one 10,000 BTU air conditioner, and 36 50-watt fluorescent lights, 3 or 4 exhaust fans, and enough juice to power a water pump. If the load is too high, I might want to consider LED lights. And what about the impact of adding additional containers?
Do I have to have an electrician determine this? Everything would be installed by a licensed electrician and would be done to code. I need this info before I can get an estimate from the local utility.
It's a lot. Each container would need about the same electrical service as an average house, and you'd spend several hundred dollars a month in electricity. The utility will happily set it up for you, but this doesn't seem like a wise plan compared to using a purpose-built greenhouse. Also, that many lights will produce a lot of heat in such an enclosed space, more than the air conditioner would suck out.
posted by miyabo at 3:37 PM on April 26, 2018
posted by miyabo at 3:37 PM on April 26, 2018
Definitely do the analysis for LED's. But not just off the shelf from ebay, optimize for crop. This is being done by a bunch of folks, I'd contact some of them like Freight Farmer as an example. Between cost of electricity and optimizing the light spectrum, LED is probably the best option.
posted by sammyo at 4:35 PM on April 26, 2018 [1 favorite]
posted by sammyo at 4:35 PM on April 26, 2018 [1 favorite]
Yes, this is a lot of heat. 11,000 watts is almost 38,000 BTU per hour. You would need four of those air conditioners.
Biggest savings would be to replace the 1000W lights with fluorescents. That would greatly reduce your thermal and electrical load.
I wouldn't necessarily spend the extra money on LEDs. Fluorescents are much cheaper and nearly as efficient as LEDs. If the lights are on 24 hours a day, it might tip the balance to LEDs to get a payback in a reasonable amount of time -- less than 24 hours a day, probably not.
posted by JackFlash at 4:39 PM on April 26, 2018
Biggest savings would be to replace the 1000W lights with fluorescents. That would greatly reduce your thermal and electrical load.
I wouldn't necessarily spend the extra money on LEDs. Fluorescents are much cheaper and nearly as efficient as LEDs. If the lights are on 24 hours a day, it might tip the balance to LEDs to get a payback in a reasonable amount of time -- less than 24 hours a day, probably not.
posted by JackFlash at 4:39 PM on April 26, 2018
Best answer: Is that load per container? Or a group?
gregr: "92 Amps = 11,000Watts / 120Volts"
The utility will supply at least 240V (typical house service). Which halves the Amps and service size.
At any rate; unless you have more than maybe someday on adding additional loads and the containers will be less than 100' from the pole I'd ask for a house standard 200A drop to your container. The difference between a 60A barely cover load service and 200A quadruple your initial install service is a essentially a few hundred dollars for larger wire.
I'd have the electrician install a main disconnect (this way you can make service changes without having to pull a meter) exterior service (to keep the humidity away from the electrical service). Exact details after that (before really, this is just what I'd do) TBD after consulting with your electrician.
Your utility might be willing to terminate as a dip service. Doing so would allow you to keep your service physically independent of any one container. Or you could bring your service into a container that isn't used for growing. You'll need storage and office space after all. Though be aware you can't/shouldn't store chemicals in your electrical room.
If you have firm plans to expand past 4X growth then you'll want to bring in 3Ø power possibly at 600V. You'd save money on wire and your A/C units and fans will be more efficient (and smaller).
posted by Mitheral at 8:08 PM on April 26, 2018 [2 favorites]
gregr: "92 Amps = 11,000Watts / 120Volts"
The utility will supply at least 240V (typical house service). Which halves the Amps and service size.
At any rate; unless you have more than maybe someday on adding additional loads and the containers will be less than 100' from the pole I'd ask for a house standard 200A drop to your container. The difference between a 60A barely cover load service and 200A quadruple your initial install service is a essentially a few hundred dollars for larger wire.
I'd have the electrician install a main disconnect (this way you can make service changes without having to pull a meter) exterior service (to keep the humidity away from the electrical service). Exact details after that (before really, this is just what I'd do) TBD after consulting with your electrician.
Your utility might be willing to terminate as a dip service. Doing so would allow you to keep your service physically independent of any one container. Or you could bring your service into a container that isn't used for growing. You'll need storage and office space after all. Though be aware you can't/shouldn't store chemicals in your electrical room.
If you have firm plans to expand past 4X growth then you'll want to bring in 3Ø power possibly at 600V. You'd save money on wire and your A/C units and fans will be more efficient (and smaller).
posted by Mitheral at 8:08 PM on April 26, 2018 [2 favorites]
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8*1000 = 8000W for lights
1*1200 = 1200W for air conditioner
36*50 = 1800W for fluorescents
So maybe, 11,000W not including pumps/exhaust/etc.
Amps = Watts / Volts.
I'm assuming you are in the US and your equipment uses regular 120V power (pretty much anything you buy off the shelf that's not a stove/clothes dryer/etc).
92 Amps = 11,000Watts / 120Volts
posted by gregr at 3:09 PM on April 26, 2018