200 amp sub panel to unattached garage

[mx842]

I'm building a post frame, medal siding pole barn/shop behind my house. When I built my house I knew that one day I would build a building out back so I had 400 Amp service installed at the time. This means I have two 200 amp service panels side by side that one was supposed to be for the house and the other was supposed to be left empty for the proposed outside building.

As luck would have it the electrician put half the house in one box and half in the other and it was all buttoned up by the time I saw what he had done so I just left it as it was until now I need the juice for the building.

I spent most of the day yesterday moving circuits out of one box and running them into the house panel box. I left a few circuits in the box that will go to the garage like the receptacles and ceiling lights in the attached garage, my well pump and some outside lights and moved the rest to the other box.

This freed up the second panel for the use to my shop. The shop is around 200 feet from the main breaker panel and I am using a 4 wire Aluminum service cable that is, 4/0 -4/0- 2/0- 4. This is going into 21/2" conduit and will be buried out to the new building. The problem I find myself in now is how do I connect this big azz wire to my 200 Amp panel at the house? I thought about drilling and tapping the buss bar then adding studs for terminal connections but I'm not sure if this is a good idea or not.

I know I could get an outside 200Amp disconnect and go in through the meter base box but that would mean I would have to have the power company come out and pull the meter so I could connect there but that would probably require some kind of permit and inspection from the county and I don't want to open up that can of worms.

I have heard of people talking about some kind of connection kit you can buy to connect into the main service panel to go out to a sub but I can't find anything out about these for 200 Amp service. All I can find is 100Amp breakers that will fit into my box.

 

[pattenp]

I'm just curious, why do you need 200A to your detached garage?

Edit: After thinking about it, if you don't have pass-thru lugs at the main breaker I think you're stuck. Even then you'd have to pull the meter to connect your service to the pole barn.

 

[mx842]

I'm just curious, why do you need 200A to your detached garage?

Edit: After thinking about it, if you don't have pass-thru lugs at the main breaker I think you're stuck. Even then you'd have to pull the meter to connect your service to the pole barn.

4 welders, 1 8x8 powder coat oven, 2 smaller ovens, Bridgeport mill, Lathe, saws, drills, lighting, heating, paint booth, air circulation/ cleaning system, plus a few more things.

This is an older Crouse Hinds panel box( before they started putting the pass through connectors in them. The new box in the shop has them but the house ones don't. I guess I'll have to do some more figuring on this......just like everything else nothing is never easy I guess.

 

[BigGMC]

Can you swap the boxes (to get pass through lug in house)?

 

[mx842]

Can you swap the boxes (to get pass through lug in house)?

I could but besides all the work involved I would still have to pull the meter to switch over the house one and that would probably involve a permit of some kind. I'd like to keep the inspectors away as long as I can if possible. Even though everything has been done like it should be I just don't want to go there because of everything else that happens during a build like this.

 

[pattenp]

Even with all the stuff you have are you just a one man operation? Are you going to be running enough equipment at one time to really need 200A? You may be surprised that you can get by with 100A.

Edit: Oh yeah.. forgot about the 4/0 wire. That's not going to fit in a 100A breaker.

 

[mx842]

Even with all the stuff you have are you just a one man operation? Are you going to be running enough equipment at one time to really need 200A? You may be surprised that you can get by with 100A.

Edit: Oh yeah.. forgot about the 4/0 wire. That's not going to fit in a 100A breaker.

Well right now I'm a one horse show but if I ever get this thing built and can start up my operation I'll have to get some help. I haven't been in too much of a hurry because the economy still ***** and from what the SC did today it may never get back barring another revolution.

Actually I'm trying to get something started so my youngest son will have something to fall into. He's pretty good with his hands and is rather artistic so custom powder coating just may be the ticket for him. and yes that big azz wire seems to be a slight setback but I think I still can find some kind of connector that will work. I found something on e-bay today that just may do the trick but I'll have to wait until it gets here to see how it works out.

 

[Aceman]

You need a sub feed lug kit, it'll look similar to this, depending on what brand of panel you have. Snaps in like a big breaker, for 200 amp it'll probably take up 4 panel spaces.

http://quinbyhardware.com/Products/...LUG-KIT/ELECTRICAL/PANEL-BOXES/SIEMENS-ENERGY

This is only 125 amp rated, but Siemens makes one that's 225 amp, I believe. It's been a couple of years since I bought one...

 

[mx842]

You need a sub feed lug kit, it'll look similar to this, depending on what brand of panel you have. Snaps in like a big breaker, for 200 amp it'll probably take up 4 panel spaces.

http://quinbyhardware.com/Products/...LUG-KIT/ELECTRICAL/PANEL-BOXES/SIEMENS-ENERGY

This is only 125 amp rated, but Siemens makes one that's 225 amp, I believe. It's been a couple of years since I bought one...

I think this is something like I just got off e-bay only it is for 200Amps. Thanks for the link, I spent 4 hours of my life looking through all of the stuff they had listed and got some good ideas for other stuff I need to get done.

 

[ripper70]

I have same set up as you. I installed a 400 amp service with 2- 200 amp disconnects so i could kill power to shop and house separate. Maybe they can add another disconnect to your main 400 amp panel?

 

[Executive]

Way too many things that could be done wrong here.

You need a disconnect in the main house, a disconnect in the garage panel, ground rods at the garage, FOUR conductors run to the garage, proper bonding of metal piping in the garage, GFCI protection for receptacles, and if you will be welding, your local electric utility's engineering department will probably want to know about it.

Consider calling a professional licensed electrician for this one.

Chris

 

[pattenp]

Okay.. you got my attention. Why?

Way too many things that could be done wrong here.

You need a disconnect in the main house, a disconnect in the garage panel, ground rods at the garage, FOUR conductors run to the garage, proper bonding of metal piping in the garage, GFCI protection for receptacles, and if you will be welding, your local electric utility's engineering department will probably want to know about it.

Consider calling a professional licensed electrician for this one.

Chris

 

[Executive]

Okay.. you got my attention. Why?

The transformers used in residential and light commercial are sized by the utility based on load diversity. This means that the loads on the transformer are generally light and spread out enough that no user is taxing the system extensively at any given time. Add a decent size welder, which is a purely resistive load and draws high current and all of a sudden that transformer is too small. The utility will resize their transformer to accommodate this type of change in the usage pattern.

Chris

 

[Charles (in GA)]

Most welders found in home/light garage use draw no more amps than the backup heat strips in the home's air handler..... and the load it very intermittent, weld for a short period of time, then stop, then weld again.

Charles

 

[justsam]

Is this an issue of current load or an issue of Power Factor for the utility?

I would think that any older welder would be seen as an inductive load, as opposed to resistive. If being used in a DC mode, than they would also introduce non linearity due to the rectifiers. Newer, portable light weight welders are typically switch mode devices, and like the millions of computer power supplies on line cause there own issues in regard to Power Factor.

I have 400 Amp, single phase service at my property, and I have not had PG&E ask what type of load might I present them.

 

[mx842]

The transformers used in residential and light commercial are sized by the utility based on load diversity. This means that the loads on the transformer are generally light and spread out enough that no user is taxing the system extensively at any given time. Add a decent size welder, which is a purely resistive load and draws high current and all of a sudden that transformer is too small. The utility will resize their transformer to accommodate this type of change in the usage pattern.

Chris

Huh? why would a transformer designed to be fed by 19,500 volts and rated for 400 amp service give a rip what you hook to it as long as it's the same phase and you don't go stewpid and really overload the service with big heavy 25 or 50Hp motors that run 24/7 all the time. 400 Amps is 400 amps no matter how you read it and the equipment has to be able to handle that load regardless of what is hooked to it within that range.

I'm not trying to start a pizzin match but when i built my house i knew i was going to someday move my operation back home and was the reason for the upgraded service. I figured it would be much cheaper that doing an upgrade later and also keep the inspections and county tax collectors out of the loop as long as I could.

Actually I don't need all that much power for what I have going on but I always like to go with more than needed and when If ever I need more I'll upgrade to 3 phase but that will likely never happen.

Besides all of this I have done most all of the things you brought up that in your opinion needs a professional. Not trying to take anything away from the trade that's for sure but I am able to do this kind of work and more than willing to do it myself to save money and time and also get it done like I want it.

I have the 4/0 4/0 2/0 4, four wire cable already laying on the ground in 2 1/2" schedule 40 conduit ready to be buried. I have my two 8' ground rods 6' apart at the building and wired to the sub panel. There will be 2 more ground rods, one in my welding room and another in the back of the building that is also connected the the ground system with #4 copper wire. I do have a disconnect at the house....my second 200 Amp panel. I have another 200 Amp, 40 space panel box already installed in the shop so that should take care of my two needed service disconnects and yes I am aware that the rec boxes in the barn need to be protected by GFI circuits and have them ready to be installed where needed. Thanks for your insight and word of caution it is duly noted.

 

[mx842]

Most welders found in home/light garage use draw no more amps than the backup heat strips in the home's air handler..... and the load it very intermittent, weld for a short period of time, then stop, then weld again.

Charles

Most of my welders are inverters and don't use that much current even my dynasty 300 when welding thick aluminum at full bore won't draw much over 20 amps if that when welding. The largest load In my shop is my big powder coat oven that has 3 3600w burners and when the oven is cold it takes around 20 minutes to get up to 400 degrees then I have it set up so that one of the burners drops off line and the other two cycle on and off as needed to keep the temp where it needs to be.

Someone already questioned the need for so much power and he was correct in that you would be surprised at just how little is needed for everyday needs. This is true but I want what I can get if needed because if it is there and I'm not using it, it is not costing me. but if I need it and don't have it that will cost me lots of money and time and those things I find myself in too short of supply of.

 

[Executive]

Huh? why would a transformer designed to be fed by 19,500 volts and rated for 400 amp service give a rip what you hook to it as long as it's the same phase and you don't go stewpid and really overload the service with big heavy 25 or 50Hp motors that run 24/7 all the time. 400 Amps is 400 amps no matter how you read it and the equipment has to be able to handle that load regardless of what is hooked to it within that range.

I'm not trying to start a pizzin match but when i built my house i knew i was going to someday move my operation back home and was the reason for the upgraded service. I figured it would be much cheaper that doing an upgrade later and also keep the inspections and county tax collectors out of the loop as long as I could.

Actually I don't need all that much power for what I have going on but I always like to go with more than needed and when If ever I need more I'll upgrade to 3 phase but that will likely never happen.

Besides all of this I have done most all of the things you brought up that in your opinion needs a professional. Not trying to take anything away from the trade that's for sure but I am able to do this kind of work and more than willing to do it myself to save money and time and also get it done like I want it.

I have the 4/0 4/0 2/0 4, four wire cable already laying on the ground in 2 1/2" schedule 40 conduit ready to be buried. I have my two 8' ground rods 6' apart at the building and wired to the sub panel. There will be 2 more ground rods, one in my welding room and another in the back of the building that is also connected the the ground system with #4 copper wire. I do have a disconnect at the house....my second 200 Amp panel. I have another 200 Amp, 40 space panel box already installed in the shop so that should take care of my two needed service disconnects and yes I am aware that the rec boxes in the barn need to be protected by GFI circuits and have them ready to be installed where needed. Thanks for your insight and word of caution it is duly noted.

I'm just speaking from experience. I've been in the trade for over 30 years. When I am doing a job and do a calculated load for service size, that information goes to the serving utility. National Grid and every local municipal light utility specifically asks if there will be any welding equipment.

Look at it this way: on an overhead service, a typical transformer size is 15kva or 15000 volt-amps. At 240 volts, this is only putting out 62.5 amps and may serve four or more residential customers. Utility transformers are very conservatively rated, but even an intermittent load from a decent size welder will reduce the life of that can. The utility wants to know so they can upgrade the transformer to accommodate such load, that's all.

Chris

 

[Aceman]

I'm sorry, but I highly doubt the utility company is going to upsize a transformer because one guy has a welding hobby in his garage at night. From what I've seen they would rather work that existing transformer a little bit harder than replace it with a larger one.

The members on here are welcome to call their utility and see what they say, but don't be surprised if they don't do anything about it.

 

[Executive]

I'm sorry, but I highly doubt the utility company is going to upsize a transformer because one guy has a welding hobby in his garage at night. From what I've seen they would rather work that existing transformer a little bit harder than replace it with a larger one.

The members on here are welcome to call their utility and see what they say, but don't be surprised if they don't do anything about it.

You miss the point. The utility makes the call. If they are already maxed out on the transformer sizing, they will proactively replace the can. It is the utility's call all the way. It's not the customer's problem.

And the OP suggested that this was going to become more than a hobby.

Chris