I'm building a detached garage soon. I plan on tapping off my meter base and running buried feeder cable to the garage. My power company has okayed this as Milbank makes a double tap for my meter (K4977-Int). My only concern is that I also want to upgrade to 400 Amp service in the future and 200 Amp service in the garage. The Milbank tap only accepts 1/0 wire, but 4/0 wire is hardly more expensive and can handle the future 200 amp service. Is it okay to use a wire reducer for now, install the 200 Amp breaker box in the garage and run with it for a few years. Upgrading the whole service right now will break the budget and the garage will have to wait a year. Or have no power for a year.
Detached Garage Power
- Thread starter Skooterj
- Start date
pattenp
Well-known member
Deleted..Spoke too soon.
I had to step back and think about it. I'm not 100% sure but I think because the conductor size limit is 1/0 you may be limited to the ampacity that #1/0 will give you if using reducing pins to get the 4/0 down to 1/0. These conductors will be unprotected from the source so the 200A main in the subpanel would need to be reduced to the ampacity of 1/0. I'm sure someone will shed more light on it if I'm not correct. You can always not use the 200A main breaker and backfeed a 125A or 150A breaker for the time being.
I had to step back and think about it. I'm not 100% sure but I think because the conductor size limit is 1/0 you may be limited to the ampacity that #1/0 will give you if using reducing pins to get the 4/0 down to 1/0. These conductors will be unprotected from the source so the 200A main in the subpanel would need to be reduced to the ampacity of 1/0. I'm sure someone will shed more light on it if I'm not correct. You can always not use the 200A main breaker and backfeed a 125A or 150A breaker for the time being.
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Terry D
Well-known member
Some pictures of your meter might help. I am thinking you will have to put a disconnect with over current protection at you meter to feed the garage sub panel. If this is a standard meter socket. it will get really crowded in there with all those wires, plus You will have no where to land the equipment ground for your garage feeders, Unless you would mount a lug. The problem is that you would have to remove and rework all of that when you mount a new meter socket. Do you really need 200 amps in the garage. How far is the garage from the house.
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dcg9381
Well-known member
Pictures would help. Around here, we do 320/ 400A service as a dual lug meter base and then immediately split off into two panels. The panels then provide breaker protection for the down-stream circuits of whatever size you want.
The reducer pins are rated for the full 4/0 wire size amps. The only real concern I have is the Milbank k4977 doesn't have an Amp rating. But the garage will only pull 30 amps top right now. Plans for more equipment later, but I don't want to run 1/0 cable now and have to trench 4/0 cable in two years.
I can't access my meter socket without removing the POCO tag. I know it is fed from below and exits out the rear into my wall then down conduit into my basement 200 Amp main breaker box. I'm doubt the garage will ever really need 200 Amp, but I thought 200 amp for everything would be fine when I built the house.
Patten, by backfeed, you mean get the 200 amp box, put a 100 amp breaker in it and feed through that for now? Is that legal? Do I just label the 200 amp breaker as inoperable and list the 100 Amp as the main? Can the 200 be removed?
pattenp
Well-known member
Yes. Just tape and label 200A main as not used and identify the backfed 100A as main. The 200A main possibly can be removed but then the hole in the cover needs to be dealt with. I'd just leave the 200A in place. The backfed breaker will need a hold down kit.
Patten, thanks. Looks like I can actually pull the 200 Amp breaker and replace it with a 100 for now in a Square D box. Would require the reducer pins on both ends. Just have to make sure not to lose the 200 breaker, don't want to buy one of those in a couple of years, pricey...
Okay, talked to POCO and Milbank rep about this. They said as long as I only feed a 100 Amp breaker for now, I'm good. POCO said reducers are common on long runs to help with voltage drop. POCO said I can crimp on reducers or splice a short piece of 1/0 on the end. Just remember to remove the reducers when I upgrade service. Thanks everyone.
pattenp
Well-known member
Just as I thought. The reducer pin are fine when using larger conductors for voltage drop, but not used to exceed the max conductor size of the lug to obtain a higher amp usage.
alfredeneuman
Well-known member
The splice to 1/0 will have to be made with a crimp connection also.
Keep in mind that crimps are only listed for use with certain crimpers (usually the manufactures' own brand).
I have a friend that works for a electric supply house, so hopefully he can lend me a set of crimpers. Otherwise Ill have to go with short pieces of 1/0 splices. Maybe put a box by the meter for now if I can't make room in the meter box.
pattenp
Well-known member
Why can't a splice/reducer be used? No crimper required.
wyliesdiesels
Well-known member
Do you really want all that unfused wire on your property?
you have no way to shut it off if something goes bad.
Is the PoCo your AHJ?
you have no way to shut it off if something goes bad.
Is the PoCo your AHJ?
Terry D
Well-known member
I agree 100 percent on this. Wether it is required or not. I would have a disconnecting means with ocp at the house. Even if he took it to a j box, reduced the wire down to 100 amp and feed it out of his main panel for now.
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alfredeneuman
Well-known member
I should have qualified that with a "probably" or "most likely".
If the POCO wants a crimp on the pin reducer (they're available with screw connections also), they most likely will require a crimp on the splicer/reducer as well.
Terry D
Well-known member
Pulling the meter is not the proper or safe way of disconnecting power in an emergency. Pulling a meter should only be done by authorized trained people that are approved to do so. This is why, starting with the adoption of the 2020 NEC, outside disconnects will be required on all new services. Your state is presently in the 2008
I would install a 200A fusible service rated disconnect within 6’ of the meter and run 4/0 4 wire feeder to the garage and leave the 200A main in the panel. Then install a 110A set of fuses in the disconnect. Label the disconnect “Service Disconnect for Garage”
Wayne
Wayne
wyliesdiesels
Well-known member
thats on the PoCos side of the meter and not your problem. anything after the meter is your responsibility
pulling the meter with a load running through it is not a good idea. I know a firefighter that was permanently scared by an arc flash resulting from him pulling a meter
alfredeneuman
Well-known member
I should have qualified that by saying "most likely" or "probably"
If the POCO required a crimp connection to be used with the pin reducer (which are also available in set screw form) they most likely would require on to be used on the splicer/reducer as well.
alfredeneuman
Well-known member
My best "guess" is it's an underground service, where the PoCo land the wires directly to the incoming meter lugs and has jurisdiction up to the meter, as opposed to overhead where the contractor runs the wires to a weatherhead and the regular AHJ inspects it.
I used to work for a small town and was in charge of disconnecting service for non-payment. I've pulled dozens of meters. I was not the most popular guy in town... I was thinking about a disconnect next to the meter box, but have a couple of concerns.
1. Someone in the future thinking it turns off the whole house, when it only turns off the garage.
2. Having to run 4/0 4 wire instead of 4/0 3 wire adds about $2 a foot plus the cost of the disconnect.
1. Someone in the future thinking it turns off the whole house, when it only turns off the garage.
2. Having to run 4/0 4 wire instead of 4/0 3 wire adds about $2 a foot plus the cost of the disconnect.
I was actually looking at a disconnect with pass through lugs, but feeding the current house through the pass through lugs is its own problem. As I stated earlier, my current house is fed out the back of the meter box. In order to used the disconnect, the main service cable would have to leave the side of the meter box, go into the pass through disconnect box, RETURN to the meter box and then out the knockout in the back of the meter box. I'm still considering this option because the main breaker in the pass through disconnect would kill everything, and I could install a 100 amp breaker for now and upgrade to a 200 amp breaker later when I get my 400 amp service. But I get conflicting information if I can run the service cable from the disconnect BACK into the meter box.
wyliesdiesels
Well-known member
except were not talking about the PoCos service lateral to the line side of the meter.
he consulted the PoCo on a feeder tap on the LOAD side of the meter. just the reason why i asked him that question
Terry D
Well-known member
You would label the disconnect
You have to run a 4-wire feeder to that garage no matter what. Even when you upgrade to your 320/400 service at the house, there should be a 200 amp disconnect feeding you garage sub panel.
Terry D
Well-known member
Like we asked earlier, we need pictures of you existing set up. Why cant you bring the pipe up from the garage on your house by you meter. Have it go to a J-box to splice and reduce it down to #2 cable, take that cable and feed it with a 90 amp breaker out of your main panel. When you upgrade your service, replace the J-box with a 200 amp disconnect with breaker and ****** or conduit to your new 320 meter. Some planning will have to be done as far as location to make it a easy switch over. Your only extra cost would be a j-box, a 90 amp breaker, connectors and the #2 SER
Why would I have to run 4 wire to the garage if it is a parallel service in a separate building? The first point of disconnect will be at the garage panel.
Feeding off a 90 or 100 Amp in my main panel requires me to put another hole in the house, something I'm really trying to avoid.
Ignore the part about generators, and this is what I want to do.
Feeding off a 90 or 100 Amp in my main panel requires me to put another hole in the house, something I'm really trying to avoid.
Ignore the part about generators, and this is what I want to do.
wyliesdiesels
Well-known member
not if the feeder is coming straight off the meter
Terry D
Well-known member
I understand that, guess i shouldn't have said "no matter what" but didn't you also suggest to overcurrent protect it pretty much in post #16
I never meant to apply that coming off the load side of the meter and feeding a panel in a separate building with a 3-wire feeder is a code violation. I believe 230.40 Exception #3 would allow this.
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Terry D
Well-known member
Why would I have to run 4 wire to the garage if it is a parallel service in a separate building? The first point of disconnect will be at the garage panel.
Feeding off a 90 or 100 Amp in my main panel requires me to put another hole in the house, something I'm really trying to avoid.
Ignore the part about generators, and this is what I want to do.
You can do that. But I would personally want a way of shutting the underground feeders off if needed, other than having to remove the meter. But that's just me. Check with your POCO if you are even allowed to remove a meter. Besides the fact it would kill your house also, its just convenient. Even with me being a licensed master electrician, I have areas here where I have to call the POCO to remove it. Also, when you bring those unfused wires into your garage, how far is it going to be to get it in the panel. All building wiring is supposed to be OCP. Check with your AHJ for the maximum distance, here for example, some areas are 6 ft and some are nothing.
Actual pictures would really help
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wyliesdiesels
Well-known member
yes i did. but the OP doesnt want that so 3-wire it is....
Terry D
Well-known member
If that's a standard meter socket, I would think it is going to be crowded bringing another set of 4/0 in there
Hey, I'm coming back to this because I've changed track a bit and have a question at 230.40 Ex 3. Decided I will never need 200 Amp at the garage, so looking at running 90 Amp through 2-2-2-4 MHF instead. If I run the second set of service cable out of the meter base and run them to a 90 Amp disconnect mounted on my house, thus provided protection for the cable buried to the garage, wouldn't the disconnect cause an issue because the disconnects aren't grouped, as the garage one is on the outside of the house and the house one is in the basement? Is it really allowed to run the unfused service out to the garage, but running a safer, fused option is a code violation?
wyliesdiesels
Well-known member
Does your meter even have dual lugs?
Milbank k4977-int