Wiring in a newly built detached shop......

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Old 07-12-08, 11:37 PM
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Wiring in a newly built detached shop......

Ok guys I will give you as much informed information as possible so that I wont waste to much of you time

This is my first post and want to thank you in advance for your help.

Here we go............

I have a new 12X20 building (wood structure on concrete block piers) that will be utilized for storage in the loft area and as a shop on the main level. I will be running various power tools but probably not more than 2 simultaneously. Plus a radio kicking in the back ground. I will also probably install a small refrigerator, a small cube style one. Of course the lighting which I plan on having 4 double bulbed fluorescent on the main level and 1 100 watt bulb in the storage area. I currently do not have a need for 220/240 but still want to run it because you can never tell. I am a jack of all trades but a master of none and it is hard to tell what I will get in to over the next several years.

The building sets 140 ft from my electrical service entrance for my home. I have 100 amp main breaker box and I plan on using an existing 50 amp breaker that is currently running the 220/240 volt service for my range stove outlet. This outlet does not need power because I have a gas range. The renovator of my home plumbed and wired it so we could make the choice.

Due to drop over that distance (I rounded to 150 when entering to be on the safe side) the online calculators are saying that I need to use either #6 copper or #2 aluminum. Is this an accurate assessment?

I found 2-2-4 aluminum direct burial service cable for .97 a foot that I want to use for this project. 2 hots and the neutral.
from the 50 amp breaker to the sub-panel at the building. Then tie the ground and the neutral together at the sub-panel via the bonding bus. Is this correct? I know that a 4 wire set up would be the preferable way to go but I am on a budget.
 
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Old 07-13-08, 12:26 AM
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Originally Posted by Jarhead1 View Post
I found 2-2-4 aluminum direct burial service cable for .97 a foot that I want to use for this project. 2 hots and the neutral.
from the 50 amp breaker to the sub-panel at the building. Then tie the ground and the neutral together at the sub-panel via the bonding bus. Is this correct? I know that a 4 wire set up would be the preferable way to go but I am on a budget.
2008 Code, which you need to follow for this install says you can't do it as stated above. You'll need an EGC with your feeder.

215.6 Feeder Equipment Grounding Conductor.
Where a feeder supplies branch circuits in which equipment grounding conductors are required, the feeder shall include or provide an equipment grounding conductor in accordance with the provisions of 250.134, to which the equipment grounding conductors of the branch circuits shall be connected. Where the feeder supplies a separate building or structure, the requirements of 250.32(B) shall apply.

KC
 
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Old 07-13-08, 03:13 AM
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OK........Since I am still in the planning phase this is mot that big of a deal.........

So I need to wire in my branch circuit coming off of my 50-amp breaker with 2-2-2-4 aluminum direct burial. My question with this is due to the large diameter of the #2 will it seat properly into the breaker?

I plan to bury this at 18 inches and then back fill 6 inches and then lay 1 1/4 schedule 40 conduit and then fill to grade. I want the conduit for any further expansion that might occur later.

I have called the power company for a dig test and the local building inspector so he can come out and do a walk through with me.

Like I stated I am very much in the planning phase of this project so please any and all input is appreciated.
 
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Old 07-13-08, 03:43 AM
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Your calculations are good, but check with your inspector on the depth of your trench. He may require 36" or at least 24". Another thing to consider (I did this on my shop) is to have the POCO make a separate drop and meter for your shop. It may cost you less to have them supply service directly to the building than it would be taking off your small panel to begin with. 100 amps doesn't leave much for your house once you send 50 amps to the shop. And, yes, you will need the 240 volts eventually. I rewire all my major tools to 240 volts mainly for quicker spool up speed.
 
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Old 07-13-08, 04:04 AM
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Thanks for the response............

I dont believe I would want do go with the option putting direct service to the building because it is areial from the pole. Plus I have several large trees that would be in line with it.

I will check with the inspector and see what the depth should be.
 
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Old 07-13-08, 06:48 AM
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You can get adapters to connect the #2 and 4 wires to the existing terminals in your panel.

However, I'd be tempted to use a junction box and tie to a short bit of #6 (probably a conduit with THHN in it), which will connect in your main panel, using no adapters (but split bolts or butt crimps though), and less space in the panel.

Here, we have a 100A service (but with electric range/dryer/hot water), and still have plenty of capacity to have our barn on a 60A sub (#6 thwn in conduit to the overhead feed cable to the barn), although it just runs a few lights, power tools, and in season, a couple of heavy electric motors (1/2 HP to 1 1/2 HP), and if needed, a welder (most of our welding is done in the shop, with its own 100A service.)
 
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Old 07-13-08, 08:12 AM
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Ok........I am still trying to get my head wrapped around the type of cable to go with.

Some one give me there opinion on this..........

Lay the 2-2-4 aluminum service cable through oversized conduit and pull a pull string with it. Replace the double pole 50 amp breaker with a single pole 40 amp breaker. Then have the sub-panel at the building with its own grounding rod.

Like stated I do not have the current need for 240v as of right now..........With the oversized conduit and string I could easily pull another #2 aluminum wire if that need ever occurs.

Thoughts comment?
 
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Old 07-13-08, 09:02 AM
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Originally Posted by Jarhead1 View Post
Ok........I am still trying to get my head wrapped around the type of cable to go with.

Some one give me there opinion on this..........

Lay the 2-2-4 aluminum service cable through oversized conduit and pull a pull string with it. Replace the double pole 50 amp breaker with a single pole 40 amp breaker. Then have the sub-panel at the building with its own grounding rod.

Like stated I do not have the current need for 240v as of right now..........With the oversized conduit and string I could easily pull another #2 aluminum wire if that need ever occurs.

Thoughts comment?
All that just to avoid running one more conductor? I would not do it like that.

You'll probably end up saving money in the long run pulling everything now...

KC
 
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Old 07-13-08, 02:05 PM
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Jarhead.,,

If you run that way The electrical inspector will deny it to you due the code and also Per the NEC code if you are running the subfeed panel from my past experanice it much easier to run 2-2-2-4 direct bural cable now or run in the conduit with #2's alum and be done with it and you will have no issue with code.

To find 40 amp single pole breaker IMO it is not very good idea to do that. Yeah you can get it but almost all the big box store don't stock large single pole breaker in that size at all.

Ya never know what kind of 240 volts load you will add so if you set up so that way it is allready to go all you have to is get correct wire and breaker for the 240 v circuit.

Normally cable / wires like that big I useally buried at least 24 inches [ 600 MM ] deep or deeper.

Merci,Marc
 
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Old 07-13-08, 05:37 PM
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Oki-Dok......I get the picture here.......don't have to beat my head off of a wall....

2-2-2-4 aluminum direct burial it is then.......

Any advice on the set up of the sub panel as far as separating the circuits?
 
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Old 07-13-08, 06:33 PM
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Do go ahead with the extra conduit or at least burial-rated flexible conduit. But that's so you can use it for low-voltage ... doorbell, TV, phone, LAN.

I know a lot of stuff can be done wireless now but it's nice to have the reliability of wired available, even if you find out wireless works fine.
 
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Old 07-14-08, 07:56 AM
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When installing the sub panel the neutral and ground should not be connected together. The panel will have a jumper from neutral to the case, which should be removed. You then install a separate ground buss block. These blocks are available where you buy the panel. The circuit neutrals would be connected to the neutral buss and the ground to the ground buss.

The four conductor cable you are buying is probably designated SER for service entrance remote. at the SE (main panel) the neutral and ground will be (indirectly) connected, at the remote panel they will not be connected.

The ONLY place that ground and neutral should be connected is at the main SE panel or individual devices, stove, dryer etc. that are DIRECTLY connected to the main panel. Devices connected to the remote panel should not have neutral and ground connected. For a stove, dryer, etc. this means that a strap connecting neutral and ground needs to be removed and (usually) a 5 wire cable and plug needs to be installed - two hot (red and black), neutral (white) and ground (green). In some cases where the device ONLY uses 220 there would be no neutral.
 
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Old 07-14-08, 08:39 PM
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I purchased the 2-2-2-4 aluminum direct burial service cable.......very reasonable at $1.43 a foot.

I also purchased a GE 125 amp 8 space mail lug load center.

I have a trencher rented for the Wed. so that way I don't break my back or worry how deep to trench. I am going 36 inches and then back filling 12 and laying low voltage flex conduit for any thing that I might want later.

I want to make sure that I have the way to wire this in correct. At the house breaker box 2 blacks are the hots and they go to the 2 pole 50 amp breaker........the black with white stripe goes to the neutral bus bar and the green goes to the ground bus bar. This is done with the 100 amp main off. Then I will then turn the main back on and leave the 50 amp off.

At the building the 2 blacks will go to the main lugs and then the black with white stripe goes to the neutral bus bar. The green again goes to the ground bus bar. I need to drive a copper rod and run #6 solid to this as well.

Any thing that sounds wrong here?

Also in one of the previous post some one mentioned that there is an adapter that will be needed to attach the large aluminum to the 50 amp breaker. Can someone tell me what these are called?

Last question (For the moment) When I bring the wire out of the trench up the side of the house and from ground level to where it enters the shop floor can I protect this with portion of the wire with conduit?
 
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Old 07-14-08, 09:07 PM
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Originally Posted by Jarhead1 View Post
I purchased the 2-2-2-4 aluminum direct burial service cable.......very reasonable at $1.43 a foot.
What type of wire is this? This really has my concern. I hope its not SER type cable.

Originally Posted by Jarhead1 View Post
I also purchased a GE 125 amp 8 space mail lug load center.
YOu need a disconnect at the outbuilding, might as well get a 100 amp main breaker panel, but the minimum has to be a disconnect rated at 60 amps.

Originally Posted by Jarhead1 View Post
I have a trencher rented for the Wed. so that way I don't break my back or worry how deep to trench. I am going 36 inches and then back filling 12 and laying low voltage flex conduit for any thing that I might want later.

I want to make sure that I have the way to wire this in correct. At the house breaker box 2 blacks are the hots and they go to the 2 pole 50 amp breaker........the black with white stripe goes to the neutral bus bar and the green goes to the ground bus bar. This is done with the 100 amp main off. Then I will then turn the main back on and leave the 50 amp off.

At the building the 2 blacks will go to the main lugs and then the black with white stripe goes to the neutral bus bar. The green again goes to the ground bus bar. I need to drive a copper rod and run #6 solid to this as well.

Any thing that sounds wrong here?

Also in one of the previous post some one mentioned that there is an adapter that will be needed to attach the large aluminum to the 50 amp breaker. Can someone tell me what these are called?

Last question (For the moment) When I bring the wire out of the trench up the side of the house and from ground level to where it enters the shop floor can I protect this with portion of the wire with conduit?
 
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Old 07-14-08, 10:06 PM
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I think what Chris was saying is make sure the cable is rated for direct burial.

Also as I stated earlier the ground and neutral need to be isolated at the panel at the shop end. Remove the neutral to case (ground) strap and purchase the accessory ground block and install in the box. At the shop all neutrals (white) go to the neutral buss and grounds to the ground buss. The neutral is not connected to ground in any way at this box. Ground the box frame to an approved ground which in your case sounds like it would probably be a driven rod.
 
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Old 07-14-08, 10:42 PM
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Thanks for the clarification.........Yes it is direct burial rated.......it is marked as USE-2 or RHH or RHW-2.........I get what your saying as far as the ground and the neutral goes........In no way are they connected on either end........White goes to neutral bus bar and green goes to the ground bus bar...........As far as a disconnect goes as long as long as I do not exceed 6 swipes I don't need a main disconnect at the building sub-panel do I?
 
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Old 07-14-08, 10:51 PM
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That correct for 6 wipes normally I useally throw in main breaker and be done with it anyway due some of the subpanel will really load up pretty fast in future ya never know when that will happend.

For the USE dircet buiral cable normally I buried at 24 inch [ 600 MM ] but if going be in area where you get pretty good traffic like driveway I go deeper.

Most trencher do have adjustable depth control so you can varies a bit depending how deep you can set it up pretty easy just run the trencher first few feet then stop check the depth if you are over 600MM { 24 inches } you are fine with it.

Before you do it make sure you call dig hotline they will come out and make a quick check to see where the buried cables like phone , tv, gaz , city water etc but for privite owned line that kinda like wild guess depending on how it setup.

Useally water pipe or sewer pipe is the deepest one depending on the area [ if you have frost in ground so expect the pipes in much lower in the ground ]

Merci,Marc
 
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Old 07-15-08, 12:02 AM
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If you are feeding this from an existing remote panel then, yes, neutral and ground would be separate at both ends.

If however you are feeding this from a main panel, one feed directly from the street, that panel should have neutral and ground connected and also be grounded to a water pipe (if you have public water) or a good ground (rod etc.)

It is the remote panel(s) that should maintain separate neutral and ground. In other words neutral and ground should only be connected together at one point, the main panel in an entire system.
 
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Old 07-15-08, 03:44 AM
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Originally Posted by Jarhead1 View Post
As far as a disconnect goes as long as long as I do not exceed 6 swipes I don't need a main disconnect at the building sub-panel do I?
If you read the instructions on most panels, they do not qualify as "Suitable for Service Equipment" without a Main Breaker, just look inside the can for a label.
 
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