A couple questions

[ishiboo]

Okay, I know the correct answer for the question but I'm looking for some additional input.

My property has 3 meters right now, the house has 2 and it WAS a duplex, and the barn has one. The barn is approximately 115' from the house. We currently have 100A service at the house and it meets our needs.

With the current service entrance being busted, and the fact we'd like to add a propane generator with automatic transfer switch, I'd like to power the house completely from the barn and eliminate 2 meters ($17/month), separate power bills (they will not combine), etc.

1. Since the house already has correct grounding as well as the barn, I'd like to run 4/0 4/0 2/0 without ground between the two, and leave the two separate ground points. I know in a typical sub panel I would run 4-wire, however do you think this is logical and acceptable?

2. The run will be approximately 160'. At a 200 amp service, this gives me a maximum continuous load of 160A. The voltage drop calculator I am using gives me a 1.8% drop at 240v... I do use 240v and not 120 since I have the two legs, correct? 120 which would give me 3.7%... would that be acceptable? I know >3% is right at the line.

3. My current panel in the barn is a QO. A 100A breaker on the current QO will not handle 4/0. How do you recommend I get between the two? I am thinking a disconnect switch and then running a smaller copper rated for 100A between the two.

Thanks in advance... this is an emergency as we have no well water, so I have to execute fast!

 

[ishiboo]

Of course its 200A per leg so I need to use 120v for the calculation, in addition I'm finding the run is closer to 200' than 160' when I factor everything in.

This is going to be quite expensive.

 

[Aceman]

This sounds like a cluster.

Fix your original service to get the water going. This is way too much work to take on without having water.

Even doing this for a living with a shop full of electricians behind me, I'd probably still recommend getting the old service fixed while we sourced parts and ordered material to get the whole place swapped over to a transfer switch and subpanels. As to your questions:

1. 4 wire.
2. 4/0 AL is fine, and yes you use 240v for the calcs.
3. I usually set a j-box with insulated taps/distribution blocks to reduce down on wire sizes.

Now my turn:

1. Where will the ATS be installed electrically? Between the meter and barn panel? Since you're using an ATS it must be capable of carrying the FULL connected load. It also needs to be service rated if it's right after the meter.

2. How are you planning on picking up both services on the home? I'd probably jerk both meters off the house, put a panel in place of one of the old meters, the one closest to the barn. Refeed that inside panel right out of the back, and then run a conduit from this new outside panel underground to the other service location on the house to refeed that panel. 4 wire to everything. Seperate neutrals/grounds in all existing panels that were refed.

 

[ishiboo]

This sounds like a cluster.

Fix your original service to get the water going. This is way too much work to take on without having water.

Even doing this for a living with a shop full of electricians behind me, I'd probably still recommend getting the old service fixed while we sourced parts and ordered material to get the whole place swapped over to a transfer switch and subpanels. As to your questions:

1. 4 wire.
2. 4/0 AL is fine, and yes you use 240v for the calcs.
3. I usually set a j-box with insulated taps/distribution blocks to reduce down on wire sizes.

Now my turn:

1. Where will the ATS be installed electrically? Between the meter and barn panel? Since you're using an ATS it must be capable of carrying the FULL connected load. It also needs to be service rated if it's right after the meter.

2. How are you planning on picking up both services on the home? I'd probably jerk both meters off the house, put a panel in place of one of the old meters, the one closest to the barn. Refeed that inside panel right out of the back, and then run a conduit from this new outside panel underground to the other service location on the house to refeed that panel. 4 wire to everything. Seperate neutrals/grounds in all existing panels that were refed.

Appreciate your help. Everything I can find says 4/0 will be insufficient for 200A service at that length, are you positive?

The water is already fixed, the service to the upstairs of the house is on its own meter and has its own service entrance, so temporarily we're good... just no dryer. I have a dryer in the barn and can always run some 10-3 if need be.

There is an issue fixing the old service, in that my local inspector does not know if it can be fixed or if it would have to be immediately brought up to code. There is no disconnect below the meter, and the service entrance runs 30' to get to the panel. I would like to temporarily run a new service entrance cable from the meter to a junction box on the house, and use the existing service (which is cemented into the house). The final fix involves digging a hole and boring the big hole.

1. Yes. The ATS will be a 200 amp with a 30kw generator, it will run everything we have for typical loads. I'll use a couple contractors if need be to shut off specific loads. It's not in the immediate plans, will probably be installed mid-next year.

2. The upstairs is being renovated and will have a panel which is a sub-panel off the first floor, for simplification of wiring. The new feed from the barn will come into a 200A panel at the house, and run upstairs inside to a 100A sub. For now, the whole house will be fed with one 100A breaker which is plenty, until I upgrade the service panel at the barn. We currently live downstairs only while we work on the upstairs.

The issue I face is this is my first time in the town and not the city, and our building inspector is also our electrical inspector, who has a full-time job doing something else. He's not sure whether I can temporarily fix the service entrance without bringing everything up to code, and what "everything" includes he's also not sure of. So I am waiting for him to hear back from our state inspectors, who are apparently furloughed.

The POCO will not reconnect without the inspector calling them, they believe... though they are calling me back tomorrow to let me know if there's a workaround since I have such an issue.

 

[Aceman]

Appreciate your help. Everything I can find says 4/0 will be insufficient for 200A service at that length, are you positive?

For now, the whole house will be fed with one 100A breaker which is plenty, until I upgrade the service panel at the barn. We currently live downstairs only while we work on the upstairs.

What makes you think you will have excessive voltage drop on those 4/0's when it sounds like you use less than 100 amps as it is?

 

[Aceman]

Alright, calc'ed out the 4/0's. You can go 179' before you hit 3% VD at 200 amps.

 

[BigJohn20]

1. You have to run 4-wire if your AHJ has adopted any somewhat recent code. It really is that simple.

2. If you're truly worried about the VD, just get a main breaker panel that will accept both 150A and 200A MBs and slap a 150A MB in there. Like Aceman says, the VD is good at that length. Do you realistically see yourself in a situation where the a VD of <= 3% is going to hurt you?

3. Expensive option? Main lug sub-feed kit. Inexpensive Option? Junction box with splicer-reducers. Should run you well under $40 for the setup.

As for combining the two services, there are a number of ways to do it. A quick and dirty way of doing it is to figure out which panel is going to require the least amount of time to make splices and extend to the other panel. At that point, rip the guts out of the old panel and use it as a junction box. Then extend your circuits from the old panel to the panel you're keeping. You don't even have to go that far if you use the second panel as a subpanel of the first and just run a 4-wire feeder to it out of your main house panel. Split the grounds and neutrals and you're pretty close to being on your way.

There are other ways, and the optimal setup rides on what you want done. Do you want to have a central location to disconnect/service? Do you want to install a new panel? Do you have room in the existing panels to combine them into one?

Since you said you're in a hurry to get this done:
-4 wire feeder to panel you choose.
-100A breaker in panel that feeds a 4-wire feeder to second panel.
-Split grounds and neutrals at both panels.

 

[ishiboo]

1. You have to run 4-wire if your AHJ has adopted any somewhat recent code. It really is that simple.

2. If you're truly worried about the VD, just get a main breaker panel that will accept both 150A and 200A MBs and slap a 150A MB in there. Like Aceman says, the VD is good at that length. Do you realistically see yourself in a situation where the a VD of <= 3% is going to hurt you?

3. Expensive option? Main lug sub-feed kit. Inexpensive Option? Junction box with splicer-reducers. Should run you well under $40 for the setup.

As for combining the two services, there are a number of ways to do it. A quick and dirty way of doing it is to figure out which panel is going to require the least amount of time to make splices and extend to the other panel. At that point, rip the guts out of the old panel and use it as a junction box. Then extend your circuits from the old panel to the panel you're keeping. You don't even have to go that far if you use the second panel as a subpanel of the first and just run a 4-wire feeder to it out of your main house panel. Split the grounds and neutrals and you're pretty close to being on your way.

There are other ways, and the optimal setup rides on what you want done. Do you want to have a central location to disconnect/service? Do you want to install a new panel? Do you have room in the existing panels to combine them into one?

Since you said you're in a hurry to get this done:
-4 wire feeder to panel you choose.
-100A breaker in panel that feeds a 4-wire feeder to second panel.
-Split grounds and neutrals at both panels.

1. Sounds good, I found some 4/0 4/0 4/0 2/0 for $2.89 a foot, so I'll go that route.

2. No, I don't... nor do I see myself in a situation where I'll use over 100A. The VD guidelines I thought were a best practices concern.

3. Sounds great, I'll look into it.

I have no concerns about combining services/etc., that's already all planned and something I've done many times. Just the main run I want to get figured out properly

Gracias.