We have a 200amp Main Breaker Box on a Pole. We want to run aluminum wire down to a 100amp Sub Panel approximately 200' away. What size wire should we use to minimize the drop in amperage. We will bury the wire in PVC Conduit. The Sub Panel is only going to run a few small appliances and lights. It will be powering an outdoor kitchen and a few other lights. Also how do i connect the wire in the main on the neutral bar. I am assuming the one wire will be really thick to attach to that bar which has tiny screws.
What Size Aluminum Wire for 100amp Sub Panel
- Thread starter mamabum
- Start date
pattenp
Well-known member
Use 2/0 Al if you want a full 100A service with less than 3% voltage drop. You will need to buy lugs to fit the wire to the bars. Your best option is to use 2/0-2/0-2/0-1 Mobile Home Feeder.
Edit: It will really help to know where you are. MHF may not be available in your area.
Edit: It will really help to know where you are. MHF may not be available in your area.
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Labradorian
Well-known member
I concur. it's the 200ft that will make the cable larger to accomadate the the voltage drop. You can go as far as about 250ft with this size cable and keep the voltage drop under 3%.
cheers
i didnt realize you could go that far with #2.
i have MHF and its the cheapest thing to do the job.
pattenp
Well-known member
pattenp
Well-known member
Mobile Home Feeder (MHF) is a direct bury cable similar to URD. MHF can be run from panel to panel because it has a fire resistant rated insulation. URD does not have fire resistant rated insulation so it needs to be terminated on the outside of the structure. The MHF needs to be in conduit where exposed above ground and where installed inside of the structure. It's advisable to place the MHF in conduit where buried.
See this... http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet15
See this... http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet15
pattenp
Well-known member
You need to run 4 conductors. It's just like running a branch circuit. That's why the MHF 2/0-2/0-2/0-1 is a good choice. You have to have the equipment ground.
pattenp
Well-known member
You should use at least 2-1/2" PVC conduit.
Need to open my eyes
sberry
Banned
Number 2 works to about 50A. Thats a lot of power in its own right. I have gas cooking and hot water but my house is 250 ft with it and you never know you are not at the service drop.
hi guys thanks for all the help and information. now that i have researched the costs and everything and thought through what our plans are (present & future) I am wondering if maybe we should just bring 40 or 50 amps down to the pavilion. Later when we are ready to build a 750sqft cabin bring a new drop to that because it will be closer to the main. I know the extra digging will be more labor but i think it will out way the cost of the more expensive wire.
So my 1st question is what size wire should we use to get the power we want at the pavilion at 250' from the main and should we use 40 or 50amps? It will have a few lights and a few outlets with 1 outdoor frig. Nothing really big.
2nd question is for the cabin how much amperage should we give the cabin? It will most likely end up no more than 100' from the main at the back side of the cabin. We will only have minimal outlets and lights with a college frig, a microwave, 2 or 3 A/C window units and possibly an electric composting toilet. I would rather a non-electric
So my 1st question is what size wire should we use to get the power we want at the pavilion at 250' from the main and should we use 40 or 50amps? It will have a few lights and a few outlets with 1 outdoor frig. Nothing really big.
2nd question is for the cabin how much amperage should we give the cabin? It will most likely end up no more than 100' from the main at the back side of the cabin. We will only have minimal outlets and lights with a college frig, a microwave, 2 or 3 A/C window units and possibly an electric composting toilet. I would rather a non-electric
hi guys thanks for all the help and information. now that i have researched the costs and everything and thought through what our plans are (present & future) I am wondering if maybe we should just bring 40 or 50 amps down to the pavilion. Later when we are ready to build a 750sqft cabin bring a new drop to that because it will be closer to the main. I know the extra digging will be more labor but i think it will out way the cost of the more expensive wire.
So my 1st question is what size wire should we use to get the power we want at the pavilion at 250' from the main and should we use 40 or 50amps? It will have a few lights and a few outlets with 1 outdoor frig. Nothing really big.
2nd question is for the cabin how much amperage should we give the cabin? It will most likely end up no more than 100' from the main at the back side of the cabin. We will only have minimal outlets and lights with a college frig, a microwave, 2 or 3 A/C window units and possibly an electric composting toilet. I would rather a non-electric
pattenp
Well-known member
#2 aluminum to the pavilion @ 250ft will get you 40A, 50A is pushing it. And #2 aluminum to the cabin @100ft will get you 90A and that should be plenty for the cabin. 2-2-2-4 Mobile Home Feeder (MHF) may be your best option, it is direct bury, but it's best to put it in conduit. MHF does need to be in conduit where above ground and when inside the structure.
theoldwizard1
Well-known member
I must be using the Southwire Voltage Drop Calculator wrong or something !
It says you can get 60A @ 240V through a #2 aluminum direct burial wire with less than a 5% drop for over 300'.
50A @ 240V and a 3% drop is good for 245'
sberry
Banned
I do this all the time. I have ran welding machine and lights from 250 ft of 2 and never noticed a problem. My home runs on it. I have gas appliances though.
pattenp
Well-known member
sberry
Banned
A thing to remember is,,, you may not be using 50A. My super peak is about 20 with an air con on and its opposite the microwave. My voltage under load doesn't drop past 120 and I never ever know or can tell I am not right at a service, what more you want?
There is a difference in wire at the box stores. When you do this make sure there is a number 2 neutral and price it.
There is a difference in wire at the box stores. When you do this make sure there is a number 2 neutral and price it.
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Awesome thank you much for all y'all's help. One more question. I put the 50A in the main run the wire to the pavilion, 100A run wire to the cabin? At the pavilion the sub doesn't have main breaker in it but should the cabin's have a main in the sub or at least a shut off valve like a hot tub sub? Sorry i lied i have 2. What size conduit do i need to accommodate the wire? I want to have as much wire buried as possible, since we are in a heavy 80'-100' pine area. And they've been a falling lately.
Are you meaning the between brands there is a difference in quality of wire? Or they sell a different combo of wire? ie...2-2-4
sberry
Banned
Yes, there is a 2 2 4 6,, Lowes had it and Home Depot had it with number 2 neutral and might have even been 4 ground,,, don't recall now but it was cheaper to boot.
There may need to be a main or not depending on the panel that is installed. If it has more than 6 spaces it requires disconnecting means or essentially a main.
There may need to be a main or not depending on the panel that is installed. If it has more than 6 spaces it requires disconnecting means or essentially a main.
Oh so you are saying i can use 4 as the neutral and 6 as the ground? There is only 6 spots available and we will only use 3 or 4
sberry
Banned
I am saying you want to make sure the wire you get is 2 2 2 and not 2 2 4
oh ok, thanks
sberry
Banned
I was hoping for some additional splainin here from the gang as to ,,,,,,,,,,,,,,,, why?
I can tell you from sperience that 250 ft of 2 works without worrin over a small % of V drop at max load you will never put on it.
I can tell you from sperience that 250 ft of 2 works without worrin over a small % of V drop at max load you will never put on it.
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Labradorian
Well-known member
Yes I agree with you, the voltage drop is based on the amount of load you will be running on the other end. OHM's Law really. the resistance per foot of the conductor is part of the equation.
If you know your load(mind out gutter) is not going to be over a certain amount then you can get away with not over sizing your conductor. But as a electrical designer I follow code. It really depends on the situation and location and whether it gets inspected and whether the inspector got up on the right side of the bed that morning.
sberry
Banned
We want a full size N here to minimize V drop on any 120V load.
wyliesdiesels
Well-known member
Theres specific code requirements that have to be met in order to be able to run a reduced neutral! I dont remember the code section off the top of my head at 4:30am....sorry!
sberry
Banned
In this case its simply or pretty much a V drop issue. A single load or any out of balance is 120V. If we were running the same wattage 240 it wouldn't matter.
sberry
Banned
Most of the worlds power runs down aluminum wire.
pattenp
Well-known member
Size has nothing to do with needing conduit or not. The type of wire and where it's run dictates whether or not conduit is needed.
ok guys, i have appreciated your help so much and making this project a lot easier to get everything completed. The pavilion looks great. I'll post pictures soon of the handyman work you have helped me to create.
I do have another question for you. We are getting a water well put in and they need a 30amp double pole breaker. What size wire do i run from the "said" pole to the well and should i run copper? The distance will probably also be 250'. It is about 150' west of the pavilion but fairly closer to the same distance from the main pole.
I do have another question for you. We are getting a water well put in and they need a 30amp double pole breaker. What size wire do i run from the "said" pole to the well and should i run copper? The distance will probably also be 250'. It is about 150' west of the pavilion but fairly closer to the same distance from the main pole.
pattenp
Well-known member
What is the amp draw of the well pump? This is needed info to determine voltage drop to size the wire since you're talking 250'.
wyliesdiesels
Well-known member
Man thats gonna be a long run for a well pump!
pattenp
Well-known member
Copper is better, but aluminum will work just fine. It's all a matter of how much money you're willing to spend.