220 volt question

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  #1  
Old 07-22-05, 10:27 PM
shenders1
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220 volt question For Roger Please

Hi All.
I have a new shed that needs electric service and a no longer used 220 outlet from a stove that is no longer needed.
It is on a 40 a breaker in the main panel.Can I connect to this circuit with a box in the ceiling and continue with new #8 wire underground about 120 feet to a sub panel in the shed.
1. I need 220v for a compressor.
2.I need some (6) outlets at 20 amp.
3. If so,how many wires do I need 3 or 4 and do I need additional grounding?.Iv'e heard yes and no on the ground rod question.
All the new outlets I bought are 15a rated..will they work or do I need to get 20a outlets.
The 120v 20a welder is the only concern here.
Thanks a million.
Steve.
 

Last edited by shenders1; 07-30-05 at 02:56 PM.
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  #2  
Old 07-23-05, 02:45 AM
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If this stove was only 220 volt with ground (no neutral) and not 120/220 volt with ground (neutral included) then you will have to run new 3 conductor cable with ground from the panel. If the existing stove cable is 3 conductor with ground...ie....Hot-Hot-neutral-ground then you can use it. I have seen a few aluminum wire branch circuits to stoves if you have aluminum wire post back with that information.

You need to give some thought to what you are operating in the shed as far as amperage ratings for the equipment if your main panel is full. You dont want to overload the main panel. A demand load calculation for the main panel is always a good idea to make sure it can support the load in the shed.

You will need a sub-panel in the shed. If the sub-panel is subject to the weather you will need an outdoor type. I would use an MLO sub-panel (no main breaker). Most that are less than 100 amp only give you 2 slots and four circuits if you use the tandem style breakers. At the major home centers the 100 amp is probably your best buy and normally give you 6 slots and 12 circuits. You do not need 100 amp but you do not have to feed it 100 amps you can just use the 40 amp breaker already in the house panel. If you havent bought the wire already moving up to #6 awg will give you a bit better voltage drop at 120 feet and also let you move up to a 60 amp breaker if the demands of the shed increase someday.

Since you have chosen direct burial you will need to transition from the stove cable (if used) to uf-b cable 8/3 with ground. You will need at least a 21 cu.in. junction box (bigger is better) that stays accessible to splice the wires. The uf-b needs to be sleeved in conduit for protection from damage till underground 24". Use a pvc sweep at the bottom of the pvc. Note that UF-b is a flat wide cable that is a #$#** to strip. It also takes some bigger than normal pvc conduit to sleeve with. Then trench 24" deep to the shed. Mount the panel as close to where you enter the shed with the cable as possible to stay within code for a disconnect means. If your plan is to enter the shed then run to the opposite wall or something then you will need to install a disconnect where you enter the shed then run from the disconnect to the panel.

Grounding: You want to seperate the neutral bar and ground bar in the panel. Do not bond them together. You may have to buy a ground bar kit for the panel to accomodate this seperation. You want to purchase a 5/8".. 8'
.. copper ground rod. Drive it into the ground all the way till slighly below the surface. It should be as close to the panel as possible. Purchase enough #6 solid bare copper grounding electrode conductor to run from the panel to the ground rod. Then connect to the ground bar in the panel and use a groundbar clamp (sometimes called an acorn) to attach to the ground rod.

All 120 volt outlets in the shed must have gfci protection if readily accessible. Example....if its behind a refrigerator is doesnt need it. You will need a light at the entrance to the shed. The 220 volt compressor does not need gfci. I would dedicate one circuit the the welder. Determine the receptacle by the plug on the welder. If you are unsure as to the electrical requirements of the welder then post back with that information and one of the professionals here will get you straight with what you need. The compressor is a motor circuit and is treated somewhat differently. If you will post back with all nameplate information that would be great. You may already know what you need.

Hope this helps get you started
 

Last edited by Roger; 07-23-05 at 06:57 AM.
  #3  
Old 07-23-05, 06:26 AM
shenders1
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Thanks Roger

You have helped me greatly.THANK YOU.
Here's hoping I have a 4 wire circuit,Iwill check it today.
Also, would a 40 or 60 Amp ground fault breaker in the panel protect everything in the shed?
Thanks again for your help.
Steve.

If aluminum branch circuit is that bad?. Iwill let you know.
 
  #4  
Old 07-23-05, 06:39 AM
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I wouldnt use ground fault on the feeder. The most economical way is to just install a gfci receptacle as the first device in the 120 volt circuit then wire to its load terminals and protect everything down stream from it. Or you could use gfci circuit breakers in the subpanel but they are expensive and more subject to nuisance tripping IMO.
If you would like some interesting reading on methods to get power to outbuildings garages,sheds,barns etc read this....

http://www.selfhelpandmore.com/homew...rage/index.htm

If you choose to use conduit instead of uf-b only thing that changes is you go to individual wires #8 or 6 awg thhn/thwn black, black, white(neutral) and #10 awg green ground wire. This will be good thru 60 amps. After that you would have to change out the wire to accomodate more amperage. You will need 1" sch.40 pvc underground and sch.80 pvc where it emerges from the ground. Glue all your pvc together running a pull string as you go. Then pull the wires thru.

You could use 3/4"pvc but 1" will make things easier.
 

Last edited by Roger; 07-23-05 at 06:51 AM.
  #5  
Old 07-30-05, 02:49 PM
shenders1
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Question for Roger Please

Hi I have run just a 20 A underground wire to my shed for lights etc for now.I have to pull the 220 later as time permits.
I purchased a 100A feeder panel,without main breaker and need to run my 120 v wire in it and connect it to the panel.
I have the usual three wires.
My question is I see where the black and white connect in the panel but where do the grounds connect.To the neutral bar all the small screws with the white?They seem to be connected together in the panel.
Directions mention bonding the panel.Do I need to do this using for now 120v from the house, i know I do when I run my bi g wire later on.
Thanks for any help.
Basically a long underground 120 v extension and install it Correctly in my new panel for now.It is on a ground fault in the house panel already.
 
  #6  
Old 07-30-05, 07:27 PM
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When you pull the 220 line later, you'll need to abandon the first line. You're only allowed one feed to a detached structure.

If you panel did not come with separate grounding and neutral bars, you'll need to buy and install a separately sold grounding bar kit. Grounding wires and neutral wires must be electrically isolated in this subpanel. Do not bond your neutral to the panel (throw away whatever bonding device was provided with the panel).
 
  #7  
Old 07-30-05, 09:22 PM
shenders1
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Getting close....

If you panel did not come with separate grounding and neutral bars, you'll need to buy and install a separately sold grounding bar kit. Grounding wires and neutral wires must be electrically isolated in this subpanel. Do not bond your neutral to the panel (throw away whatever bonding device was

It came with the neutral bar only.
So, I should buy a grounding bar kit for the box and attach all my grounds(the ones I am newly wiring in the panel AND the ground coming in from the house panel on the 12-2 wire from the house to it.

1: Do NOT bond the neutral in panel
2: Do I need a external ground rod in the ground attached to the panel as well or just connect all grounds to the ground bar kit Thanks a lot.
 
  #8  
Old 07-30-05, 09:55 PM
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Go back and reread Roger's excellent posts. He already said everything I just said, as well as answering your latest question. Yes, you need a grounding rod.
 
  #9  
Old 07-30-05, 09:58 PM
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It came with the neutral bar only.
So, I should buy a grounding bar kit for the box and attach all my grounds(the ones I am newly wiring in the panel AND the ground coming in from the house panel on the 12-2 wire from the house to it.
Yes, you need to purchase a ground bar kit for the panel. You will see some swaged sets of holes in other locations for mounting ground bars. Mount your new ground bar in thase holes. It must be a ground bar for the panel you have or it may not fit the hole pattern. You will attach the ground wire coming into the panel from the 12/2G feed to the ground bar not the neutral bar.
If by chance this panel is a square d 100 amp your ground bar Part# is PK7GTA

Do NOT bond the neutral in panel
Thats correct

Do I need a external ground rod in the ground attached to the panel as well or just connect all grounds to the ground bar kit
There is an exception to 250.32 of the NEC that says if you only run a 15 or 20 amp 120 volt feed to the garage and only run one branch circuit (only one breaker in the sub-panel) to lights and receptacles from your garage panel then you do not need a ground rod.

So you can make that choice in your situation as you describe it.

I think if you are pretty certain that you are going to upgrade to 220 and more circuits I would go ahead and put in the ground rod following previous instructions. The #6 grounding electrode conductor will connect to the ground bar not the neutral bar.

Do you know how to install a ground rod? Methods...options etc...?

EDIT: John I'm about 99.9% sure that exception allows not installing a ground rod in the situation he describes but as I said I think the better installation is to install it.
 

Last edited by Roger; 07-30-05 at 10:49 PM.
  #10  
Old 07-30-05, 10:42 PM
shenders1
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Many Thanks

Thanks You are a godsend.
I have never installed a ground rod.
I bet you have.
I will be running just a couple circuits for now.

Yes it is a square D.
 
  #11  
Old 07-30-05, 11:03 PM
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The best method IMO is use a rotary hammer drill with a ground rod driving adapter. You can rent these and in decent soil conditions they can drive the rod in 2 or 3 minutes.

Some people use T-post drivers like you use on farm fences.

And some people are unfortunate and must use a sledge hammer.

Since you have never installed one, you want it to be as close as possible to the sub-panel location. No matter what method you use take a wooden 2x4 about 4 feet long and drill a 3/4 to 1 inch hole 4 or 5 inches from one end. Have a buddy slide the rod thru this hole and steady the ground rod as you drive it preferrably vertically until it is about 6 inches below the surface. Dig a trench over to the garage to where your #6 solid copper exits the exterior wall. Put the #6 in the trench and connect it to the rod with one of these....
http://www.waltonemc.com/Newsletter_...groundrods.htm

To give you a better image on connecting the grounds and neutrals (white wires).... All white wires from 120 volt 14/2G or 12/2G branch circuits will connect to the neutral bar (the one that came installed in the panel). All bare wire grounds will connect to the ground bar that you are going to install.

There should have been a green bonding screw in that square d panel usually it is taped inside. If it is factory installed you need to remove it and throw it away as John mentioned earlier.
 

Last edited by Roger; 07-30-05 at 11:45 PM.
  #12  
Old 09-09-05, 06:37 AM
shenders1
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Gonna pull 220

Hi All.
I have a new shed that needs 220V electric service and a no longer used 220 outlet, but only 3 wires, from a stove that is no longer needed.Stove outlet is on top floor and I just plugged in the stove 3 wire plug, drilled a new hole in the floor and let it hang,taped off in the basement ceiling awaiting a cover box.I did not see a ground on the stove
It is on a 40 a breaker in the main panel.Can I connect to this circuit at the location of the old stove with a box in the ceiling and continue with new ,wire underground about 120 feet to a 220v outlet in the shed. It will only be used for a 220 V 7 hp compressor.What do I do for a ground?It only has 3 wires.
Thanks.
Thanks for your previous help Roger and all.
 
  #13  
Old 09-09-05, 07:29 AM
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You cannot do what you propose. You are proposing to use the old range cord as permanent wiring, which it is not designed for.

Now you might (depending on the wiring) be able to place a junction box instead of the range receptacle, and run from there, but I still donít recommend this. You would be better off running a new line from the panel.

As for only running a 240 line to the shed, I think you are being short sighted. If you are going to go through the work of running a line, run four wires. Allow for the possibility of a 120 volt tool being used. Why limit yourself to a 240 volt appliance, and only one at that? Run a new line from the main panel to a small sub panel in the shed. From this sub panel run a line for your compressor. You can also run lines for lights and for 120 volt receptacles.
 
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