200 amp service upgrade

[Amber Gold]

The sugarhouse is run off the house's main panel on a 100 amp breaker and cable. The main panel is fed by a 100 amp feed, but I upgraded the panel a couple years ago to a 200 amp panel (the house has a 100 amp shutoff before the panel). Running the sugarhouse and house off a 100 amp feed is cutting things close and I'd like to upgrade the service to 200 amps, but I've gotten conflicting reports on what size wire to run. One person tells me to use 250 MCM 75C wire, and another said I could use 4/0 SER. Which is it? Do they need to be run in conduit? It'll drop 18" from the meter socket before it enters the house where it'll run across the bottom of the floor joist to get to the main panel.

Thanks for the help.

[whalems]

2/0 if copper or 4/0 aluminum.

[maple flats]

What is the distance? That will allow me to calculate the voltage drop on various gauges and I will give you the details. Even though you may never draw the whole 200A at once, I'll calculate it at 200A for a worst case scenario unless you specify a lower amperage. When you state the distance, if over 100', be sure to calculate the whole distance (the actual length of the wire needed) because if the sum of the ups and downs and inside the buildings is significant, it might require a larger size. As an example, I used KCMIL350 from the pole to the meter on my system. I needed 225 amps (I have large solar system) and the distance was 252' total. I could have used as small as KCMIL 250 but I would have lost up to 7-8% as I was trying to push power back into the grid on net metering. The voltage drop would have caused my meter readings to suffer some.
If you distance is 100' or less, you can easily use 4/0 aluminum, if farther I need the specifics. As an example, at 200A at 100' length,3/0 loses 5.05V, 4/0 loses 4.0v, kvmil250 loses 3.4v, it all depends on distance. If underground you need sch. 40 conduit and if under a driveway or parking area you need sch. 80 for that part only.

[red maples]

Sorry I will explain on sat. too long.

[Scribner's Mountain Maple]

I have a very similar question for you electrical geniuses. I am sending power from my 100 AMP panel to sugarhouse over a 500' distance. I want to transfer at least 60 AMP. What is the smallest wire I can use?

Will run above grade for this year, and then may consider burial for next, but will likely be able to pull in primary this summer for a 200 AMP service. Making this a Temporary solution. And why I am looking for the cheapest wire I can find adequate for the task.

I will be running 4 blowers, filter press and 3 HP Vac pump

Thanks for any advice.
Ben

[maple flats]

My figure are just going to show voltage drop. At any given voltage a motor needs so many watts to run. Watts x amps = watts, thus if thevolts drop it takes more amps to get the watts needed. Amps are like the flow in a water pipe, more amps require more push, volts are the push. With a lighter wire you begin to starve a motor and the motor heats up and heat is more resistance. This heat also shortens the lift of the motor. Cutting on wire gauge just costs you more every year to keep things going even though you saved a little on the initial install. Think of it in terms of vacuum, you can use a 15 " vacuum 20 CFM pump on 3/4" pipe to go 4000' or you can use a 100 CFM pump at 28" vac on the same 3/4" line. Both will give you the same vac at the end of the 4000'. Use 1.5" pipe and there is a huge difference. A very similar result happens when you use a lighter wire to run something at a longer distance. You need heavier wire to properly run a load at a longer distance.
I will give voltage drops on both Cu and AL for your distance and you can chose your efficiency.

[unc23win]

http://www.calculator.net/voltage-drop-calculator.html

I had wire given to me and the concern was that I was loosing too much. I used this calculator and it works good an electric co rep showed me it. You want to keep the % of drop under 10% of course the more you draw the further the more % loss there is. When I was done we did reverse calculations to see the actual loss and it was less than calculated. My loss is right about 7%. Its kinda cool because even if I shorten the length to 400 feet the percent loss will only change about 1% and if I lengthen the run to 700' the percent loss will be 10.5% Changing wire wasn't much help either because of the distance. Next year I plan on having a new service put in and then I will run 2 sets of wire the rest of the way as I have it all already to get 200 amps. Right now I have 100 amp on 100 amp breaker at house.

[Scribner's Mountain Maple]

Thanks for the link. According to this it says I can use 8 AWG with a 9.5% drop. That seems really small as I was thinking I needed 1/0 before.

The 6AWG looks better with a 7% drop with Aluminum wire at 60 AMP 600 Volts at 500 ft. And a single set of wire.

Jared, looks like we are going a similar distance. What did you end up using for wire?

Thanks.,
Ben

[Amber Gold]

PSNH runs the cable from the pole to the meter socket, and I run the cable from the meter socket to the panel. Total distance from the meter socket to panel, including extra for connections is about 45'.

Thanks

[unc23win]

Thanks for the link. According to this it says I can use 8 AWG with a 9.5% drop. That seems really small as I was thinking I needed 1/0 before.

The 6AWG looks better with a 7% drop with Aluminum wire at 60 AMP 600 Volts at 500 ft. And a single set of wire.

Jared, looks like we are going a similar distance. What did you end up using for wire?


Thanks.,
Ben
I used what they call Tri Plex what use to be service wire they don't use anymore got some for .50 a foot and some more for free. I got it from the Electric Co Op I believe it is 2AWG 66.4 kcmil. What I found was even if I run the best wire I can't gain much for now. When I upgrade the electric co will run 250' for free to service then I will handle the rest. Electric co recommended using 4th wire for neutral. Electric Rep was actually surprised at how good the wire was for such distance.

[maple flats]

If you run Triplex overhead you can use a smaller gauge wire since each hot conductor is separately insulated heavy and being open to the air it doesn't get too hot.
I would not suggest even for short term any wire that will result in a 10% voltage drop. The utility does not continuously supply you with 120/240, the actual is not steady, but it flexes up and down continuously. At times you will only get as low as 110/220. Now if you take a 10% drop at that moment, you are at 99V/198V, those numbers will burn out a motor in short time. I would recommend you keep within a 3 or even better a 2% voltage drop to keep within tollerable voltages at the times the utility might fall to 110/220. Granted, they are usually in my experience in the 115-119V/230-238V range, but you have no control over when the utility falls momentarily. Even for the 45' distance, run at the minimum 4 ga and 3 or 2 is even better. Do you have a multi-meter? If yes, just test the voltage on any circuit or in the panel box. Be extremely careful, put the black test lead on the hot terminal or if in an outlet, in the shorter slot, then touch the red to the neutral or the wide slot if in a receptical. Watch the voltage for a period of time, it will move up and down rapidly. Then have someone turn something on at the same circuit, what happens? Then have them turn on a bigger load even on a different circuit (Elec. Dryer, stove, etc), watch what happens. Now realize that this changes all the time, all day long. You need enough power if you happen to turn on a large motor at a time when the voltage is at the lowest point. Once the motor is running it is still important, but is less critical.
I would also run the 4th wire, especially if going in conduit underground. If that is the case, make the conduit large enough to hold the next expansion planned in a few years. Then you can unhook the wire in the conduit at both ends, attach the larger to it and pull the new thru the conduit as you pull the old out. If this is planned for the future, make any bends long sweeps and not short ells, a long ell is far less resistance than a short ell, and don't have 2 next to each other, plan for gradual sweeps. Then when you pull, use a wire lube for much easier pulling. Once you apply the lube you need to work quickly because it evaporates away in somewhat short order.

[maple flats]

Oh, If you run the Triplex, run 2 ground rods at the sugarhouse, with 4 ga cu ground, in a continuous loop (From the panel, to the 1st rod, to the second rod [at least 6' away] and then back to the panel. If you use 4 conductor, the ground rod only needs to be a single rod. If you hit bedrock and can't drive the rod, you can bury it in a trench laying the full length except about 6" sticking up to attach the ground wire. The trench should be a minimum of 2' deep.

[gcec]

You need to upgrade all the components of the service starting at the utility drop. 4/0 Se from drop to meter socket which also has to be 200 amp rated. 4/0 SE from meter to 200 amp disconnect . 4/0 SER from disconnect to panel And instal primary grounding at disconnect. Isolate neutral and ground conductors at main panel. Usually needs to be done by licensed electrician also inspection required

[GeneralStark]

Inspection is not necessarily required everywhere. Been working on a project here and just made the final connection to the sugarhouse today for a 200 amp service. Over 300 amps of conductor (parallel runs of 4/0 to the meter socket) for the total project. One run of 4/0 to sugarhouse (20 ft.) for 200 amp service. Also 100 amps for our home. Also buried extra 2.5" conduit in case I need more conductor down the road. Did hire an electrician for assistance and guidance but did most of the work myself. No inspection required. Utility installed a transformer on a pole on my property, but I did everything else and paid for the conduit and conductor.

Don't undersize the wire as mapleflats says. You can destroy motors and it will cause major headache in the long run. Do it right once.

[Flat Lander Sugaring]

You want to keep vd max 7%, but do what you want. i THINK Flats WILL AGREE ON MOTORS you can go 10% above and 5% below rated motor voltages. After those numbers you can very likely start doing damage to your motor(s)

By code 2008 to now, please correct me if I'm wrong (Flats) if you install a sub panel under todays code you are required to run a 4 wire from main panel to sub. Years ago you were allowed to run a 3 wire and drive two ground rods at sub panel.

[maple flats]

That IS required here. Unfortunately I do not know all the jurisdictions that do and don't subscribe to the NEC. Supposedly all should but I know of areas that do not. The NEC is the Uniform National Electrical Code, it seems all would need to follow it, being "National" but not all areas enforce it as they should.
Yes, you can go 10% above and 5% below with motors, as I pointed out above, the 5% below becomes an issue especially if you turn on the motor at an instant when the grid hits a lower voltage. Fortunately those are generally very brief, but I have seen times when voltage has fallen too much for several seconds and on a lighter gauge wire you compound that. Utilities are required to stay within a certain window technically, but sometimes they fail that. This fact may be the single biggest reason to never use a marginal wire gauge on any motor. If you are running the main feed to the sugarhouse, the RO will be your biggest draw and will be likely the most problematic if the motor failed when you need it.
Another factor should be considered too, marginal wire gauge generates heat, heat creates more resistance and thus more heat etc.

[Flat Lander Sugaring]

That IS required here. Unfortunately I do not know all the jurisdictions that do and don't subscribe to the NEC. Supposedly all should but I know of areas that do not. The NEC is the Uniform National Electrical Code, it seems all would need to follow it, being "National" but not all areas enforce it as they should.
Yes, you can go 10% above and 5% below with motors, as I pointed out above, the 5% below becomes an issue especially if you turn on the motor at an instant when the grid hits a lower voltage. Fortunately those are generally very brief, but I have seen times when voltage has fallen too much for several seconds and on a lighter gauge wire you compound that. Utilities are required to stay within a certain window technically, but sometimes they fail that. This fact may be the single biggest reason to never use a marginal wire gauge on any motor. If you are running the main feed to the sugarhouse, the RO will be your biggest draw and will be likely the most problematic if the motor failed when you need it.
Another factor should be considered too, marginal wire gauge generates heat, heat creates more resistance and thus more heat etc.

Oh I agree with you 100% on the marginal wire usage. A lot of people balk at spending more money on wire but they don't understand the consequences of cheapening out. Ill suggest to my customers once what they should run if they dont I make note of it in bill.

on jurisdictions and following NEC, the State of VT just started following the 2010? NEC 72 from 2002

[Amber Gold]

In summary, 4/0 three conductor w/ ground SE is what I need from the meter socket to the panel. Did I understand that I need a shutoff at the meter socket? So it'd go: meter socket, shutoff, panel? In NH, I can do the work, but it needs to be inspected by the building inspector. I installed a service at my woods tank a few months ago.

Another question. I want to get a 100 amp generator in the near future. I want to re-use the existing 100 amp SE cable to run from the generator to the panel and the generator will be where the meter socket is, so the cable can stay in-place. I want to put a sub-panel in to connect the generator and 100 amp SE cable to. The main panel will have an interlock switch to shutoff the main breaker and open the 100 amp generator breaker. Does anyone see an issue with this?

[Amber Gold]

Talked to the building inspector and 4/0 Al is fine, but it needs to be 3 conductor cable...$$$.

I also need a shutoff as it enters the house since the panel is on the opposite side from the meter. Can I put the shutoff outside and use a generator transfer switch and does it need to be a fused switch? Just looking for a manual shutoff. I've also seen a 4 slot panel with two 2-pole breakers and a rocker switch for a transfer switch....when one's on, the other's off. Can I do the same here? Just trying to find a cost effective solution to have a main shutoff and a generator transfer switch.

[Flat Lander Sugaring]

Code is 10 feet into building more than that has to have **** off outside. At that point you have made your first means of disconnect now wire has to be four wire from that point on . I think a manual transfer switch would qualify. Neutrals an d grounds will all be under same lug at that point then all be separated after that.
Now NYSEG in new York only lets you go 5 feet inside house before needing disconnect .

[Amber Gold]

Thanks.

What's the logic behind the shutoff?

[Flat Lander Sugaring]

Thanks.

What's the logic behind the shutoff?

not really the disconnect it the insulation on the wire they want to limit inside a dwelling if I remember correctly fumes if it burns. The disconnect doesnt have to be outside it can be at the 10' mark inside also.

[maple flats]

[QUOTE=Scribner's Mountain Maple;236147]

The 6AWG looks better with a 7% drop with Aluminum wire at 60 AMP 600 Volts at 500 ft. And a single set of wire.

How are you using 600V in your calculation? For that you will need a step up transformer at the source and then another, a step down before the panel in the structure. While wire is tested at and insulated for and labeled 600V you do not have 600V, you have something in the range of 220-240V unless you bought 2 very expensive transformers. I don't normally discourage those who want to "do it yourself" it seems to me you are getting in over your head. Even if you do the labor, hire an electrician to guide you, if you can find one that will do that.
The power feed to my meter is 2 conductors 350 kcmil and 1 conductor 250KCMIL, and I paid just over $18.00/ft and needed 265' at 3.5#/ft.
Any voltage drop costs you at the meter in every electric bill. If you plan for 7% VD you will pay about 7% more in the bill. Generally, 2.5% is considered max, since you are planning a short term approach and plan to run a new service next year (will that really happen?), you might get away with a 3.5% drop if your utility voltage never falls below 228V. You need a multimeter for this and need to spot check it under load many times for a pattern.
Dave

[1arch]

Great conversation. Voltage drop is a recommendation by the National electrical code not to exceed 5% overall from the point of service from the utilities to your utilization equipment. With that said if a motor is running under full load conditons and voltage is lower than the name plate value then as Dave said the motor could be overheated. However most motor driven equipment is or should be protected against over current either by an internal thermal cutout switch or by an external thermal protection. This will limit motor damage in the event excessive current conditions exist. On that note I have seen motor's fail prematurely due to operating for extended period's in high ambient temperatures. Heat kills...
In addition when sizing a feeder or branch circuit the NEC limits capacity to 80% actual rating for continuous loads such as an RO that will potentially operate for 3 hours or more. So anticipate a 100 amp service capable of delivering only 80 amps continuously "for 3 hour's or more" while maintaining the voltage drop within the 5%. Ensure your connections are made up tight since a poor connection could introduce higher than tolerable heat causing voltage drop.

[Swagner]

Ben: Another thing to consider about running your cable temporarily above ground is that most wires are not rated for this. The sun actually breaks down the wire as does extreme cold. As mentioned previously the less voltage drop the better. The 5% that the NEC recommends is for the Entire system. That meaning what you are loosing in voltage starting at the pole.So first voltage reading that actually needs to be taken is at the meter. If this is already low then that will make the power to your final equipment lower then you thought.Unfortunately not ever house gets the same exact amount of power to their meter. I personally install all my service risers in conduit. Makes for easier changing down the road and gives wire a little more protection. If I was going to have that much draw on my service just off one breaker I would run my main in 1/0 copper. And as stated earlier depending on the distance out to your shack depends on the size required their. But I wouldn't use anything smaller then 2" pvc out to it and make sure its cleaned well before glueing with lots if sand in the trench above and below the pipe. Good luck and feel free to ask more questions

[Flat Lander Sugaring]

Ben: . But I wouldn't use anything smaller then 2" pvc out to it and make sure its cleaned well before glueing with lots if sand in the trench above and below the pipe. Good luck and feel free to ask more questions
second that but use primer before the glue. unless you want water inside your conduit before you pull the wire and it freezes. Been there I have used primer and glue ever since never will I thaw out a buried conduit again if there are ways to stop the issue in the beginning.