Putting in a panel unless you need it will not help the size of the wire. Voltage drop is figured to the last device.

I used a common calculator to get these sizes. 3/0 AL or 2/0 copper are the wire sizes I came up with.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

500 feet is a LONG way for power circuits especially at 240v.

Quadplexed 4 wires of 3/0 AL is 7.23 a foot this can be direct buried.

2/0 xhhw copper single conductor, you will need conduit. 4.74 a foot.

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The only other way is to find 2 transformers, to buck the voltage up and then back down. GUESSING the transformer @12.5kva will cost a couple of grand each. The cost of the wire would be about 1/3 less. Which would not make up for the cost and installation of the transformers.

Time to cut distance in half, then you would be looking at 4 awg copper.

 

SW thank you so much for your reply...

One other outside the box idea can I use (2) # 4 awg (0.2043 x 2 = 0.4086) I found # 4 much much cheaper. Over all wire size at face value should work. When I hook to the panel can I have two leads under one breaker post or is there a better cleaner way to accomplish this?

I found a local source form large jobe over run

# 4. 500 ft. 4 Gauge Black Stranded Copper THHN Wire $550 x 2 rolls $1,100

2/0.500 ft 2/0 Black Stranded Copper THHN Wire $1650

 

Several problems with your idea. You would need 3 rolls of #4 and a roll of #10 for the ground. #4 copper with a load ~500 feet gives you a voltage drop of about 15v and just over 6%. Then you have to add in the cost of the conduit. You could stuff all of this in a 1" conduit but for that long of a run I would use 1 1/4".

The voltage drop is for an air conditioner is excessive. Will it work, maybe. Then the microwave or any other heavy load will start being upset with the voltage drop.
Last time I looked at ac's for my travel trailer they were running ~$800 for a 13.5k btu.
My trailer is smaller than yours.

"two leads under one breaker post" As big as this wire is you will not be able to put two wires under the same pole on the breaker. I do not understand why you would want to do that. You stated the trailer needed 220v which is a two pole 50 amp breaker.
I would also suggest that you put in a disconnecting means, like a pull out 60 amp fuseable panel (fused to 50) so you have a safe means of connecting and disconnecting the plug for the trailer. That far away it would be fool hearty not to.

 

With the cost of wire currently I don't want to risk any errors in my calculations.

OK, so cost is an object. Aluminum is your friend even if you've been told lies about it. Aluminum at these large sizes is proven as safe as copper, not least because the lugs it'll be landing on are made of aluminum because aluminum lugs are a winner.

The "it's underground" logic is dumb. That only matters if the insulation is pierced by rocks (which means you didn't line the hole with a good width of fine dirt/sand on each side of the wire). If your insulation is pierced, wire metal will be the least of your problems!

This will be burial so I'm leaning towards copper wire

Sure, if cost is no object.

Figure 2-3x the cost for copper. Your money, hoss.

Also you know copper wire is a huge target for copper thieves, right?

I am aiming for 3% loss.

More "cost is no object" eh?

NEC doesn't care about voltage drop but does say you are not to plan to load the circuit beyond 80% ampacity. In Canada they do care, but apply that same rule to say you calculate the 3% based on 80% of load. 40A in your case.

2/0 AWG aluminum wire ($6/ft for USE-2) will give 2.71% voltage drop at 40A.
4/0 AWG aluminum ($9/ft for USE-2) is 1.95% voltage drop at 40A.
1 AWG copper ($13/ft for USE-2) is 2.47% drop at 40A.
2/0 AWG copper ($20/ft for USE-2) is 1.81% drop at 40A.

I wouldn't normally recommend USE-2 for direct burial, but I needed something I could compare "apples to apples". Normally with AL direct burial you use quadplex URD or MH feeder. Fact is, they don't offer a lot of choice of copper wire designed for direct burial because nobody does that lol. Anyone silver-spoon enough to bury large Cu usually springs for conduit. That said, I wouldn't, because conduit makes it easy for copper thieves.

I'm assuming ground wires 2 sizes smaller than conductors because of 250.122(B).

One other outside the box idea can I use (2) # 4 awg (0.2043 x 2 = 0.4086) I found # 4 much much cheaper.

No go, can't parallel per 310.10(H).

Over all wire size at face value should work. When I hook to the panel can I have two leads under one breaker post or is there a better cleaner way to accomplish this?

Don't quit your day job lol. No, you can't do that. NEC 110.3.

Why do you hate aluminum? I bet if you honestly sat down and thought about it, you'd say "SAFETY". Then why are you proposing all this dangerous nonsense? See you're just all over the place.

Slow down and listen to experts. At the end of the day you want your money not wasted and the project to work. Stick with gold standard practices.

Speaking of safety, using a torque wrench on lugs is actually important (unlike aluminum). You're gonna use one, right? Aluminum properly torqued is safer than copper "gud-n-tight".

The only other way is to find 2 transformers, to buck the voltage up and then back down. GUESSING the transformer @12.5kva will cost a couple of grand each.

Now you're playing with power! Except I'd scour Craigslist, eBay and Facebook Marketplace for those transformers. They pop up from time to time for a few hundred bucks.

As for wire cost, you're now at 2x #6 aluminum for about $1.50/foot for the 3 wires.
Or #8 copper at $2.50/foot.
Aluminum loses its advantage on small wires since less of the cost is mineral value and more is the cost of the insulation jacket.

 

OK, so cost is an object. Aluminum is your friend even if you've been told lies about it. Aluminum at these large sizes is proven as safe as copper, not least because the lugs it'll be landing on are made of aluminum because aluminum lugs are a winner.

The "it's underground" logic is dumb. That only matters if the insulation is pierced by rocks (which means you didn't line the hole with a good width of fine dirt/sand on each side of the wire). If your insulation is pierced, wire metal will be the least of your problems!



Sure, if cost is no object.

Figure 2-3x the cost for copper. Your money, hoss.

Also you know copper wire is a huge target for copper thieves, right?



More "cost is no object" eh?

NEC doesn't care about voltage drop but does say you are not to plan to load the circuit beyond 80% ampacity. In Canada they do care, but apply that same rule to say you calculate the 3% based on 80% of load. 40A in your case.

2/0 AWG aluminum wire ($6/ft for USE-2) will give 2.71% voltage drop at 40A.
4/0 AWG aluminum ($9/ft for USE-2) is 1.95% voltage drop at 40A.
1 AWG copper ($13/ft for USE-2) is 2.47% drop at 40A.
2/0 AWG copper ($20/ft for USE-2) is 1.81% drop at 40A.

I wouldn't normally recommend USE-2 for direct burial, but I needed something I could compare "apples to apples". Normally with AL direct burial you use quadplex URD or MH feeder. Fact is, they don't offer a lot of choice of copper wire designed for direct burial because nobody does that lol. Anyone silver-spoon enough to bury large Cu usually springs for conduit. That said, I wouldn't, because conduit makes it easy for copper thieves.

I'm assuming ground wires 2 sizes smaller than conductors because of 250.122(B).



No go, can't parallel per 310.10(H).



Don't quit your day job lol. No, you can't do that. NEC 110.3.

Why do you hate aluminum? I bet if you honestly sat down and thought about it, you'd say "SAFETY". Then why are you proposing all this dangerous nonsense? See you're just all over the place.

Slow down and listen to experts. At the end of the day you want your money not wasted and the project to work. Stick with gold standard practices.

Speaking of safety, using a torque wrench on lugs is actually important (unlike aluminum). You're gonna use one, right? Aluminum properly torqued is safer than copper "gud-n-tight".




Now you're playing with power! Except I'd scour Craigslist, eBay and Facebook Marketplace for those transformers. They pop up from time to time for a few hundred bucks.

As for wire cost, you're now at 2x #6 aluminum for about $1.50/foot for the 3 wires.
Or #8 copper at $2.50/foot.
Aluminum loses its advantage on small wires since less of the cost is mineral value and more is the cost of the insulation jacket.

I’m not sure if you or anyone mentioned ACWU or. not but it’s the cats ass for these kinds of installs. Also make sure there’s marking tape . 500’ run from a pole to camper it’s eventually going to get hit by a excavator.

 

My wiring calculations are varying... This will be burial so I'm leaning towards copper wire

For another datapoint re: copper vs aluminum: my POCO only uses aluminum for underground service, in conduit.

 

After that long essay let me just say it's a no brainer to use aluminum. And remember you need both a ground and a neutral. The ground need not be calculated based on voltage drop.

 

If the conductors are oversized for any reason like voltage drop the grounding conductor also needs to be upsized.

 

Just for my understanding, why does the EGC need to be upsized beyond the size for a specific amperage circuit? However, I agree it seems strange having a #10 ground with 2/0 hots. There will also be a ground rod there.

 

Just for my understanding, why does the EGC need to be upsized beyond the size for a specific amperage circuit?

If you look at it this way it may make it clear. You increase the size of the energized and grounded current carrying conductors to keep the impedance low enough so that the voltage drop will not be too large for efficient operation of the loads in the trailer. You do that to keep the voltage drop down to a level that will not damage your appliances. Do keep in mind that one of the energized conductors will be the source of the fault current.

By the same thinking you also need to increase the size of Equipment Grounding Conductor (EGC) to assure that it’s impedance path back to the source is nearly the same as a shorter smaller EGC would be. The Impedance that you are trying to limit the EGC to is the one which will carry enough current to open the circuit breaker in an acceptable time.

The reason that the EGC need not be as large as the normally current carrying conductors is that it only has to carry the fault current long enough for the breaker to open. If the impedance of the EGC is kept low enough so that the breaker opens in an acceptable length of time then it will continue to be too short a time for the EGC to heat excessively before the fault is deenergized by the breaker opening on the fault current.

To Summarize, the impedance of the fault path must be held to that of the smaller conductor at a length that gives the needed ampacity with the same impedance to assure timely operation of the breaker. Since the additional length of the circuit raises the total impedance you hold that increase to an acceptable value by offsetting the increase in length with in increase in the gauge of the wire.

Tom Horne

 

Without upsizing the ground the resistance may be too large to operate the overcurrent device.

Sent from my SM-T500 using Tapatalk

 

Will POCO give you another drop at the second location with a new meter how much would that be I wonder.

 

At 220 volts, 50 amps = 2/0 copper THHN, 4/0 Aluminum XHHW
At 240 volts 50 amps = 1/0 copper THHN, 3/0 Aluminum XHHW

 

Calculations are based on 240 volts, not 220.

 

500 ft direct run from my 200 amp panel at the pole to where I will be placing the 5th wheel.

Since you said that your service is at a pole is it correct that your service is overhead?
Is there any other pole, which is still on your property or immediately adjacent to it, that is closer to the 5th wheel camper.

I am aiming for 3% loss.

Since the branch circuits in the camper are quite short you may want to calculate the wire size for a 5% drop as well. If it reduces the wire size to the next smaller available gauge it might save you some money. At 3% you need 3/0 Aluminum at 4.17% you need 1/0 aluminum. With 1/0 feeder wire you will need a #2AWG Aluminum Equipment Grounding Conductor.

I'm suggesting this because 5% voltage drop over the entire length of the conductive pathway, including the feeder and the very short length of the branch circuits in the camper should make the 4.17% voltage drop in the feeder acceptable. 3/0 down to 1/0 size should save you a few dollars.

Here is a kind of weird suggestion. Since the nominal ampacity of 1/0 Aluminum is 143 amperes you may want to consider making the feeders overcurrent protection markedly higher than the 50 amperes you want to power the 5th wheel camper. If you use a 100 ampere breaker to protect the feeder but have a 50 ampere breaker at the receptacle outlet then it becomes rather unlikely that the feeder breaker would open on an overload prior to the 50 ampere breaker at the receptacle outlet opening. That will avoid the 500 foot hike to reset the feeder breaker under most circumstances other than physical damage to the feeder. If the feeder were to get damaged then the breaker at the outlet would likely remain closed so that the camper occupant would know the problem was not in the camper. That would suggest a problem with the feeder but they would have to be electrically savvy enough to recognize it.

Tom Horne

 

Since you said that your service is at a pole is it correct that your service is overhead?
Is there any other pole, which is still on your property or immediately adjacent to it, that is closer to the 5th wheel camper.

Since the branch circuits in the camper are quite short you may want to calculate the wire size for a 5% drop as well. If it reduces the wire size to the next smaller available gauge it might save you some money. At 3% you need 3/0 Aluminum at 4.17% you need 1/0 aluminum. With 1/0 feeder wire you will need a #2AWG Aluminum Equipment Grounding Conductor.

I'm suggesting this because 5% voltage drop over the entire length of the conductive pathway, including the feeder and the very short length of the branch circuits in the camper should make the 4.17% voltage drop in the feeder acceptable. 3/0 down to 1/0 size should save you a few dollars.

Here is a kind of weird suggestion. Since the nominal ampacity of 1/0 Aluminum is 143 amperes you may want to consider making the feeders overcurrent protection markedly higher than the 50 amperes you want to power the 5th wheel camper. If you use a 100 ampere breaker to protect the feeder but have a 50 ampere breaker at the receptacle outlet then it becomes rather unlikely that the feeder breaker would open on an overload prior to the 50 ampere breaker at the receptacle outlet opening. That will avoid the 500 foot hike to reset the feeder breaker under most circumstances other than physical damage to the feeder. If the feeder were to get damaged then the breaker at the outlet would likely remain closed so that the camper occupant would know the problem was not in the camper. That would suggest a problem with the feeder but they would have to be electrically savvy enough to recognize it.

Tom Horne

This is the best idea of all of them. And thank you so much for your input. I think this may be just the solution . Do you think direct burial I will have issues with rodents, squirrel/ rabbits and those type or found pests.... What do you think about this 1/0-1/0-1/0-2 Notre Dame Quadruplex Aluminum Conductor Underground Direct Burial 600V URD

1/0-1/0-1/0-2 Notre Dame Quadruplex Aluminum Conductor Underground Direct Burial 600V URD

1/0-1/0-1/0-2 Notre Dame Quadruplex Aluminum Conductor 600V URD cable for direct burial or duct use, rated up to 200 Amps. Shop now for superior performance.

nassaunationalcable.com

 

^ great ideas from the hornet. I especially like the "don't sweat 3%" and "big breaker".

But if cost is no object, go for it lol.

 

i agree with miamicuse ,another service would be cheaper if you can get it, especially if this is going to be a perament install.

 

I'm hooking up a large 40 ft fifth wheel... 50 amp 220 service. The 5th wheel has two air conditioners, electric heater,TVs,microwave, washer and dryer, dishwasher the whole 9 yards. With the cost of wire currently I don't want to risk any errors in my calculations.

500 ft direct run from my 200 amp panel at the pole to where I will be placing the 5th wheel.

One option is a direct run of 500ft or I'm curious if i could put a panel half way and drop down my wire size.

I am aiming for 3% loss.
My wiring calculations are varying... This will be burial so I'm leaning towards copper wire

What are wire sizing options for the 2 scenarios

Any input would be greatly appreciated







View attachment 726865

Question that's come up if I use direct burial aluminum no conduit. How common are issues with squirrels and rabbits or other ground rodents?... I was planning on using conduit... But the direct burial aluminum is sounding very appealing. If you guys think it'll be fine with the creatures....

 

Well, in any direct burial installation you are required to run inside conduit down to full burial depth - the straight-down run and then the 90 degree sweep to horizontal. Your burial depth will be 24" of cover, so that should put it above most varmints. Make sure all the soil around the wire isn't full of rocks because even at 24" the soil does move, and it absolutely can press the cable into a rock and gash it. You may be trenching to 30" or 36" so you can put a good layer of sifted material below, aside and above the cable.

Of course none of this is a concern with conduit, but that invites the other kind of varmint, the one that drives pickup trucks.

 

I would not go 24" I would go ~36" . We are talking power not phone or internet.
I agree 24" is the minimum. Open field, all kinds of room for changes.

I would also acquire the underground metal tape for marking the location of your wire. Where I live it is required. Some people buy a roll of 14 stranded and put that about 1 foot above the wire. Helps a lot to have a wire down there if you have to locate the wire in the future.
Trenches for quadplex need to be clean. No rocks no debris. If your ground is rocky and you have a freeze thaw cycle you will need a sand base for the wire to lay on and to cover the wire up. Rocks are sharp and even though the insulation is tough I have seen several times when people thought a few rocks would be ok. Only to have trouble later when being out of power is a problem.

Unless you have moles/gophers the min allowed by code is fine. Critters do not dig in open fields.

Unless you by the wire by the foot I believe most of the wire comes on 500 or 1000' spools.

 

Will POCO give you another drop at the second location with a new meter how much would that be I wonder.

 

In the US many of the electrical utilities will charge a meter reading fee for having a separate meter on the same piece of property as another meter. When the fee was first instituted it could be justified because the meters were read by people who had to write down the numbers from each meter. Now that it is done wirelessly by driving by in a company pickup truck I think it's thievery but once they have a fee on their approved billing tariff they never give it up without a fight.

Tom Horne

 

Yes, and in my experience that fee is getting worse and worse. We have 2 properties with 2 service drops each. We could have easily consolidated them, but never bothered. A couple years ago, our municipal power started charging $60 per month per service, and this is a "service availability" charge which applies even if you knock all the buildings down and grow corn. I asked at length. So $240/month $2880/year. Our non-profit only has 1 public service that costs more than that to run. IRS requires you list the top 3 on the Form 990, I'm really tempted to write "#2... subsidizing municipal power".

 

That is exactly the kind of thing that I characterize as "hold up by fee!" $720 a year makes having a yard pole installed, underground conduit runs installed from a central point, or even acquiring your own High Voltage to Service Voltage transformer begin to make economic sense.

Some State Public Utility Regulatory Agencies have been putting pole top metering requirements in place which require the delivering electric utilities to meter at the pole top were that is advantageous to the customer. That means that a distribution line must be brought to the property boundary and can be extended from their at the customers expense but the metering must be done by aerial or utility vault mounted current transformers. The affect is that no matter how many individual buildings are supplied from the extended line the metering is still single point. The other form of that rule can require that a property owner with an extended frontage on the utility's right of way, which usually means a public road, can demand to have the service delivery lines extended from a point of equal access to the buildings to be supplied were the individual transformer already serving the property must be located or effectively extended to that common location. Effectively extended means that the delivering electrical utility must run the local service conductors to the identified common point and meter the supply there. Both types of rules force the delivering utility to meter at a point that is genuinely advantageous to the customer. In any place that adopts these or similar rules it will markedly ease the burden on owners of larger residential and agricultural properties, as defined by State law and not by the delivering electrical utility.

Tom Horne