Tandem Breaker as a replacement for a single breaker

Reply

  #1  
Old 06-05-13, 10:52 AM
Member
Thread Starter
Join Date: Jun 2013
Posts: 5
Tandem Breaker as a replacement for a single breaker

I ran some wire to my shed and wired one outlet, but now I need to connect this to the power in my house. Currently my breaker box is full, and there are 5 tandem breakers already in it. My idea was to replace one of the other single breakers with a tandem one and wire my new circuit into it.

The box is a Square D QOC 20MW 225 with 200 amp service.


Is this the correct way to go about this?



thanks!
 
Sponsored Links
  #2  
Old 06-05-13, 01:25 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Welcome to the forums!

Currently my breaker box is full, and there are 5 tandem breakers already in it.
Since two tandem breakers fit in each full-height breaker position, you should have an even number of tandem breakers in your panel. Do you mean piggyback breakers?

Some terminology:
  • A standard full-height single-pole circuit breaker is 1" tall, has one terminal and one handle, and can protect one 120V circuit.
  • A tandem breaker is 1/2" high - half the width of a full-height breaker - and protects one 120V circuit.
  • A piggyback breaker is 1" tall - full height - and has two terminals and two handles. It can protect two 120V circuits.
  • A tandem piggyback breaker is 1/2" tall, has two terminals ans two handles, and can protect two 120V circuits.
My idea was to replace one of the other single breakers with a tandem one and wire my new circuit into it.
If your plan is to remove either a full-height or a half-height (tandem) single-circuit breaker, replace it with a piggyback breaker, and use one half of the new breaker to supply the new circuit and the other to supply the circuit that was connected to the breaker you remove, that may work.

I ran some wire to my shed and wired one outlet,

The box is a Square D QOC 20MW 225 with 200 amp service.

Is this the correct way to go about this?
What type of wire or cable did you run to your shed, and how did you run it? What does the label on the inside of the door of your panel tell you about allowable breakers and positions?

A link to the specs for your panel would help us. A couple of pictures - one of the panel label and one of the breaker array, might also help. See How To Include Pictures.
 
  #3  
Old 06-05-13, 02:32 PM
Banned. Rule And/Or Policy Violation
Join Date: Jan 2010
Location: KS
Posts: 1,896
Tandems are not single handle. A single handle 1/2" breaker is simply called half-height, and a 1/2" breaker with two handles is a half-height tandem. Any breaker that has two handles on the same leg is a tandem. You could use tandem and piggyback breaker interchangeably in a sentence - they are not two different things.

He is saying he has five breakers that each have two handles. If it's a CTL panel that hasn't been overloaded, there should be (at least) one more space than can be swapped for a tandem.

Edit: That catalog number is just for the cover. There should be another longer number which will be the number for the 'guts'.
 

Last edited by JerseyMatt; 06-05-13 at 02:54 PM.
  #4  
Old 06-05-13, 03:57 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Tandems are not single handle. A single handle 1/2" breaker is simply called half-height, and a 1/2" breaker with two handles is a half-height tandem. Any breaker that has two handles on the same leg is a tandem. You could use tandem and piggyback breaker interchangeably in a sentence - they are not two different things.
That may be true in your area and in your experience. What I posted is true in my area and my experience. It seems there's not consensus on this.

Regardless, this should help us get some clarity.

And also regardless, we do need the # of the panel itself (the part inside)!
 

Last edited by Nashkat1; 06-05-13 at 04:21 PM.
  #5  
Old 06-05-13, 04:18 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
Twin, duplex, piggy-back, half-size...I've heard/read all the descriptors and I don't think that there is a single universally recognized definition.
 
  #6  
Old 06-05-13, 04:23 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
I don't think that there is a single universally recognized definition.
Yep. I just hope we haven't confused the OP too much!
 
  #7  
Old 06-06-13, 12:45 AM
Banned. Rule And/Or Policy Violation
Join Date: Jan 2010
Location: KS
Posts: 1,896
Originally Posted by Nashkat1 View Post
That may be true in your area and in your experience. What I posted is true in my area and my experience. It seems there's not consensus on this.
Originally Posted by Furd View Post
Twin, duplex, piggy-back, half-size...I've heard/read all the descriptors and I don't think that there is a single universally recognized definition.
Be that as it may, the word 'tandem' by definition implies 'two on one'. Is a tandem bicycle a half-sized one-person bicycle? No, it's a single bicycle that fits two people. So a 'tandem breaker' - by definition - has two handles on one device. And if you google "tandem breaker" and flip to images, you will not find a single picture of a single-handled breaker of any size.

Yes, 'tandem', 'twin', 'piggyback', and 'duplex' are all different 'regional' and 'manufacturer-utilized' words for the same thing. However, I am sorry but for that same reason I have to argue that you can not say that a tandem and a piggyback are two different things. Especially given that you are referring to a single handled device as a tandem. That's like saying 'soda' and 'pop' are two different things, with pop being a type of ice cream... I guarantee that if I were to walk into a supply house in your area and ask for a QO 20A tandem breaker (again, google it and look at the images that come up) I would not be handed a single-handled breaker.

The descriptor '-height' or '-size' refers to the device's physical size (1/2" or 1") regardless of the number of handles, and 'tandem' refers to a one-pole, two-handled device regardless of its physical size.



Originally Posted by Nashkat1 View Post
Yep. I just hope we haven't confused the OP too much!
To be honest, if anything it would be your strange terminology that would be confusing... I'd bet anything the OP knew what he was talking about.
 

Last edited by JerseyMatt; 06-06-13 at 01:01 AM.
  #8  
Old 06-06-13, 03:48 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Gee Matt, you don't think I do? Two oxen or horses yoked side-by-side are pulling in what? Tandem?

We'll see, if and when the OP chimes back in.
 
  #9  
Old 06-06-13, 06:39 PM
Banned. Rule And/Or Policy Violation
Join Date: Jan 2010
Location: KS
Posts: 1,896
Exactly. It is two units working as one. It does not imply half-sized oxen.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes