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connecting two breaker boxes.. how to connect to the old one

connecting two breaker boxes.. how to connect to the old one

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  #1  
Old 01-27-13, 09:18 AM
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connecting two breaker boxes.. how to connect to the old one

I am trying to connect an additional breaker box. I am pretty sure I can do the attachment of the wires to the new box.. it is attaching these wires [ there are 4 of them.... white.. metal and two black ones] to the existing breaker box. Can someone tell me how to do this? Thank you
 
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Old 01-27-13, 09:29 AM
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Are you connecting a sub panel to the main panel ?
Do you have a two pole circuit breaker in main panel to supply the sub panel ?

A picture of the main panel would be particularly helpful.

Your main panel should have a combination ground/neutral buss bar. You should see white wires and bare wires on that bar. That is where your white and bare wires will go.

The two black wires will go into the two pole circuit breaker that is properly sized for the wire......IT IS....RIGHT ?

At the sub panel end. The two black wires will go into the main panel lugs or main circuit breaker if supplied. Even though there may be a main breaker in the sub panel.....you are still required to have the correctly sized one in the main panel.

The white wire goes to an insulated neutral buss bar.....a bar with screws that IS NOT electrically attached to the sub panel box. This buss bar will only have white neutral wires on it.

The bare wire goes to a separate buss bar that is attached directly to the metal sub panel box. This buss bar is for ground wires only.

Any questions........ASK.....don't assume anything.
 
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Old 01-27-13, 09:30 AM
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Are you trying to add a subpanel?

I might also suggest you pickup a copy of "Wiring Simplified" to obtain a better grasp of the basics.
 
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Old 01-27-13, 11:55 AM
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ok, this is a sub panel of sorts. The one currently in use is in the basement. The new one is in a room we added on this year. We also added an upstairs..so the new box will handle all the new electricity. I can figure out how to wire the new box... I am just not sure how to add the new box to the old one. I will be able to remove 2 slots that are now used by the clothes dryer because it will be on the new panel. So I have some blank spaces for new breakers..I am just nit sure if I install a 100 amp breaker there.. and then run the new panel from that... or even how to attach it if that is the case.. Thank you for your help guys!!
 
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Old 01-27-13, 11:58 AM
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Where would they have a copy of that book for purchase? As you can tell I am desperate!
 
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Old 01-27-13, 12:05 PM
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That book is available from many places. Amazon, Barnes and Noble, Target and Home Depot.....just to name a few places.

Wiring Simplified: Based on the 2011 National Electrical Code, Richter, H. P.: Textbooks : Walmart.com


Above all......you want to do things safely.
What size is your main panel ? Main breaker size and how many breakers ?
How many amps is your current sub-panel ?
What size sub panel did you want to add ?
 
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Old 01-27-13, 03:23 PM
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Main breaker

The shut off switch has 100 on it..below on the left there are 2 50's that power the cooking stove...2 30's that power the clothes dryer [ this will be moved to new panel].. then a 20 amp then 2 30's that power our heating system.

on the right side.. there is a 20 then15 then 20,20,20,15 then 2'30's for the water heater.. was this any help? The main switch is located on the top of this panel.. and on the bottom of the new panel.
 
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Old 01-27-13, 04:00 PM
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The subpanel will be connected to the main panel using a 240 volt breaker. Since the wire is already there unless you replace the wire the breaker size will be determined by the wire size. Because it is best to leave high amp breakers in the main panel you will need to move a couple of the 15a or 20a 120 volt breakers to the new subpanel to make room for the breaker that will supply the subpanel.
 
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Old 01-27-13, 04:25 PM
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new panel

the new panel also says 100 on the main switch...
 
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Old 01-27-13, 04:30 PM
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Thank you so much Ray and everyone. Is it ok to connect everything .. then start the new panel? or should I connect it first so I can check switches/outlets/ lights as I go?
 
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Old 01-27-13, 04:34 PM
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Ray I see you are also trying to help me with the ceiling fan that has three cables... also the switch that has four cables coming from it... I really appreciate your help.
 
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Old 01-27-13, 04:48 PM
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The main breaker in the new panel only serves as a disconnect. The breaker in the main panel can be anything 100* or less. Please tell us the size wire connecting the two. I would get panel running first.

*If I recall some 100 amp panels are limited to 70 amp or less branch circuit breakers.
 
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Old 01-27-13, 05:29 PM
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There are a lot of variables in play here.

First it would be prudent to calculate your projected maximun current draw from the new panel. We know there will be a dryer, so there's 30 amps to start.
What other appliances, lights, etc will be powered off the new panel?

Second to a degree the distance between panels will be a factor in the size of the wire between panels and the 2 pole breaker in the main panel that will serve the sub panel. Your loads in amps are the main factor, but excessive distance could bump you up to the next thicker wire size in some cases.

Even assuming the dryer and 1 additional 20 amp circuit on the subpanel, that puts you up to 50 amps. I'm not an electrician, but I know a 40 amp circuit requires 8GA wire IIRC so 50 or more amps could put you up to 6 or 4ga wire. If your subpanel is close to the main it's not that big of a deal, otherwise prepare to shell out some big bucks for that heavy wire.

Are you moving the dryer? Is it possible to leave the breaker for the dryer in the main panel and just extend the existing circuit to reach the dryer and save the subpanel for lighter loads?

The 100A main breaker on the subpanel seems a bit of overkill. Again, no specific advice is intended here as I am not an electrician, but hopefully the questions I have asked will allow you to provide the specific information that will help those here that are qualified to point you in the right direction.

Remember too that if you DIY and don't get an inspectors stamp of approval, if something goes wrong your insurance company will likely use that to deny your claim.

If in doubt, ask . Hope you get it all worked out safely.

CrispyB
 
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Old 01-27-13, 09:02 PM
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The cable between the two panels is a big grey wire with the same wires that are attached to the main panel. it has four large wires. one silver.. one black and white...and two black wires..the only large thing scheduled to go on the new panel would be the dryer...everything else is just some lights, 2 ceiling fans, and receptacles.
 
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Old 01-28-13, 04:07 AM
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Not sure if that wire would pass code? Normally your inside wiring would have a white (neutral) Black Red and bare copper earth ground. Almost sounds like it could be some kind of service entrance wire.

Your voltmeter leads between the black and red wires give you 240v and from either the black or red to white or copper wires give 120v.

Distance between panels? Gauge of the individual wires? Is it copper or aluminum? If aluminum, there are extra things you have to do at your connection points to ensure a safe connection such as using an anti-oxidation compound and careful torque of the setscrews on the bussbar and then retorque at a specified later time.
 

Last edited by ray2047; 01-28-13 at 06:54 PM.
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Old 01-28-13, 08:32 AM
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The only large amps will be for the dryer because it is getting moved to the new room. Everything else is just lights, receptacles.
 
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Old 01-28-13, 08:35 AM
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The cable does look exactly like the entrance wire connecting the main breaker. I believe the electrical inspector saw that. Should I use a different kind to connect the two panels?
 
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Old 01-28-13, 08:58 AM
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You ave not given us the requested information on the cable so we can't answer. What gauge how many conductors. There should be writing on the cable. Please post that.
 
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Old 01-28-13, 06:34 PM
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Ray,

Please reread my post below that had the moderater edit added. I stated between black and red was 240v and from either black or red to neutral or ground was 120V. Is that incorrect?

Sounds like he may have something like this Aluminum SER

If so it could have 1/0 conductors which would be plenty adequate, but what would be the smallest breaker that would work in his main panel that would accept such a large conductor? For his stated loads I'm thinking a 60 amp in the main panel to feed the sub, but will that take a 1/0 conductor? Would there be an acceptable way to step down to say 6ga within a junction box just outside the main panel?
 
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Old 01-28-13, 06:42 PM
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The cable between the two panels is a big grey wire with the same wires that are attached to the main panel. it has four large wires. one silver.. one black and white...and two black wires
That sounds like aluminum SER cable, but ray is right, you need to provide the cable information from the jacket.

We know there will be a dryer, so there's 30 amps to start.

Even assuming the dryer and 1 additional 20 amp circuit on the subpanel, that puts you up to 50 amps
A dryer doesn't use 30 amps and a 20 amp circuit doesn't use 20 amps. That isn't how you add up loads.
 
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Old 01-28-13, 06:52 PM
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Crispy B, you put 120 in parentheses after red and black. That is incorrect. Neither is 120 volts. They are the two legs of the 240 volt power supply to your house. I will go back and remove my mode note and remove your parenthetical comments.

I agree best guesstimate is a 60 amp feed is all that is needed. While it would be easy to pigtail copper to use a smaller breaker aluminum while not impossible would be more problematic. But the O/P must answer our questions before we can speculate further.
 

Last edited by ray2047; 01-28-13 at 07:19 PM.
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Old 01-28-13, 07:16 PM
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"A dryer doesn't use 30 amps and a 20 amp circuit doesn't use 20 amps. That isn't how you add up loads."
Joe,

You got me on the dryer. It would be more like 22A +/-. For other circuits, I figured you would have to assume each could at some time or other be at or near their max, sort of a worst case scenario (space heaters, toaster ovens, etc)

I'm here to learn as well as help where I can. Please explain the proper method for sizing circuits/subpanels.

Thanks

CrispyB
 
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Old 01-28-13, 07:22 PM
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You use a load calc such as Single Family Dwelling Load Calculator or Residential Load Calculations - Mike Holt Enterprises I suspect though an experienced electrician would just "eye ball it" on this one. Most loads are going to be 120 volts so subtracting the 22 amps when the dryer is running that leaves you over 4500 watts on a 60 amp feed probably more then enough for lights and a few receptacles not heavily loaded at the same time.
 
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Old 01-29-13, 05:56 PM
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Joe,

You got me on the dryer. It would be more like 22A +/-. For other circuits, I figured you would have to assume each could at some time or other be at or near their max, sort of a worst case scenario (space heaters, toaster ovens, etc)
For one thing, the dryer amperage is all at 240 volts and the receptacle is at 120 volts so you cannot simply add the amperages on the breaker handles to get load. If you add the wattages you can do a correct load calculation. The link ray provided is a good residential one.
 
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Old 01-30-13, 05:03 PM
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HI, I went to Lowe's and they said that the cable [ which has 4 lines..one aluminum.. one neutral .. one black and one with black and red] that is the cable I should use to connect the two panels. I also got a double pole 50 amp to be my feeder to the new box. I will place that where the dryer breakers used to be. I hope to have the new box completely wired tomorrow. If I can I would like to put a picture on here so you guys can see how it is done.. and if you feel it is correct. Thanks CrispyB and Ray. Let me know if that is possible. Bev
 
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Old 01-30-13, 05:07 PM
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I will also check and see if there is info on the jacket.. sorry I didn't see that before. It is the same as the cable used to run the electricity into the house to the main panel.
 
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Old 01-30-13, 05:38 PM
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Name:  Aluminum Ser.jpg
Views: 5188
Size:  10.1 KB I think by your description that this is what you are working with ?
 
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Old 01-30-13, 06:04 PM
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If that is it then the solid black and black with red stripe wires are the ones you connect to the 50A breaker you are installing in the main panel and your main breaker in the subpanel.

The black with white stripe goes to the neutral buss bar where all your white wires are connected and the bare wire to the buss bar with all the bare copper ground wires are connected.

In your sub panel you want to be sure that the buss bar with all the bare copper wires is the one bonded (connected electrically) to the panel box and the neutral bar is isolated from the box and no bare copper wires are connected to that one.

I believe the reason for this is to prevent there from being 2 paths for the neutral to return to the main panel which could cause any GFCI outlets to trip.
Someone correct me if I am wrong about that or if there are other more important safety reasons.

Also, if all the conductors in your cable are aluminum, read up on making connections properly especially for tightening the setscrews and using an antioxidant compound. Do not ever join copper and aluminum together. That will cause what's known as a galvanic reaction between two dissimilar metals which causes corrosion.
 
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Old 01-31-13, 04:48 AM
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Red face

Yes Crispy that is what it looks like. Thank you
 
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Old 01-31-13, 10:25 AM
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Yes Crispy that is what it looks like.
But is it the right size? Will it even fit the breaker you plan to use in the main breaker box? If not and it is aluminum then special care will have to be used to connect it to pigtails to reduce the size.

Please answer thees questions that have been ignored:
What size cable? Look at the print on the sheath.
What size breaker will it connect to in the main panel?
in the main panel?

HI, I went to Lowe's and they said that the cable [ which has 4 lines..one aluminum.. one neutral .. one black and one with black and red] that is the cable I should use to connect the two panels.
With out specifics requested above there is no way to know for sure if that answer is correct for you.
 
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Old 02-02-13, 09:18 AM
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Is this what you needed? Here is some of the info on the cable..Type se cable ser type 2 cors 600 volts. If this is not what is needed.. what would the info look like? THanks a lot.. Bev
Type se cable ser type 2 cors 600 volts
 
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Old 02-02-13, 09:31 AM
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I thought I said it would connect to the main panel with a double pole 50 amp breaker. How would one piggy tail to reduce the size? The guy at lowes said to just attach the cable as is... I just went and checked and it will be easy to attach the black/black and red cords to the 50 amp breaker. The way it is designed it will allow that size to slide into the space.. and then be tightened with the screw. I would have to split the neutral and the ground wire and attach it to the buss bars that way. It is the way the main neutral and and ground [ aluminum] was attached in the initial installation of the main panel.

I have already learned so much from you guys.. like what a cable vs wires are ..and what double pole means..etc.. thank you so much.. Bev
 
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Old 02-02-13, 09:41 AM
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How would one piggy tail to reduce the size? The guy at lowes said to just attach the cable as is... I just went and checked and it will be easy to attach the black/black and red cords to the 50 amp breaker. The way it is designed it will allow that size to slide into the space.. and then be tightened with the screw.
Which may mean the cable is the right size or too small to be correct for that size breaker. Please don't rely on Lowes for your misinformation. The neutral has to be in a hole by itself the ground can share with another ground.
 

Last edited by ray2047; 02-02-13 at 04:52 PM.
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Old 02-02-13, 09:46 AM
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There is something that looks like it might be a #4..there is also a 12 on the wire... but no clear.# symbol.
 
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Old 02-02-13, 09:50 AM
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nothing on the cable looks like that....I am not sure what you mean about the neutral .. can it go on the buss bar in a slot of its own? Would it need piggy tailed as you earlier inferred some of that might need to be done? Thank for all your help.. Bev
 
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Old 02-02-13, 09:52 AM
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I normally correct my posts three or four times. You are reading before I correct them. Forget I ever mentioned pigtails. Markings may be a series of numbers such as 6-6-6-10

P.S. I'm so exhausted from trying to keep up with your typing I may need a nap.
 

Last edited by ray2047; 02-02-13 at 04:53 PM.
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Old 02-02-13, 10:17 AM
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I have tried and tried to read this cable.. it is a series of dots.. and you have to see it from a certain angle with the light at a certain angle..and maybe from a distance to read it... so far.. I can't.. Like I said.. there are the numbers... 4... 12...21... and 600 volts.. I will try to get more information.. and get back to you.. thanks so much..
 
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Old 02-02-13, 10:23 AM
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Red face

Ray....awwwwww take a nap.. I am sure I will be typing more soon.. but.. I am patient.. and can wait.. I just know this is just the beginning... it will be hard to finish this job.. when my son just got mad and walked out on us.. leaving us with a third more debt that stated..and it is now.. 10 months..when we were quoted three..and I have had to close my 401 K.. and still.. having to do a lot myself..because it is gone... and he has the nerve to be mad at me? I don't get it...but I know it will be hard to finish this job...because I didn't start it.. but this is the first step in finishing the wiring..and I appreciate you more than you can know....I will see what I can find out about that cable.. Bev
 
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Old 02-02-13, 10:53 AM
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ok.. this is what I have been told by Lowe;s where the wire was purchased. It is a SEU [ service entrance underground] cable. for 100 amp. the gauge size is #222 it is also known as 3/2's wire. Does this help? Bev
 
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Old 02-02-13, 11:09 AM
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If necessary pull the cable out of the new box to get a clear picture of the marking. I am probably being more of a PITA then I need to be but I want to be sure the cable is at least #6 (6-6-6-10). If I was a betting man I would say it is. Last resort buy one foot of #6 THWN wire at the hardware store and compare the wire with the insulation stripped to the wire in your cable with the wire stripped.

The pigtail was when I wasn't sure what size SE cable you had. What yo do is connect a short length of wire called a pigtail that is small enough to fit the breaker to the wire that is to large to fit the breaker.

If you are connecting to the main panel you probably will not have separate ground and neutral bars, just one or two bars that are used for both ground and neutral. Code says only one neutral wire per hole in the bus bar. On your cable that would probably be a black wire with a white stripe. The code does permit the ground to be two to a hole but best practice don't do that unless you really have to.

P.S. Hang in there. We are on the home stretch.
 

Last edited by ray2047; 02-02-13 at 04:55 PM.
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