Trying to add more 110V breakers to GE tm2420 panel


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Old 02-21-24, 12:17 PM
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Trying to add more 110V breakers to GE tm2420 panel

Hi All,

I have this old GE panel - I would like to add 8, 15 amp 110V breakers to it.

I thought I could replace the big 220\240 v breakers with thin breakers to get more openings to fit in the 110 v breakers.

I took one of the big breakers out and was going to replace it with the thin 220v breaker and add a 110v breaker next to it, it seems to me this won't work? I am struggling to figure out how the 220 and 110 is split in this old panel.

Would appreciate if anybody could offer some guidance.

I have uploaded 3 photos - one of the panel, one with the one big\thick breaker removed and one of the wiring diagram for the panel. (I note that it is a "CTL" panel)

Thank you very much.

Wiring diagram

Thick breaker out

Panel
 

Last edited by micang; 02-21-24 at 12:59 PM. Reason: Added a photo

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02-21-24, 04:08 PM
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I have this old GE panel
Unless I miss my guess, that older GE panel has aluminum bus. You probably are not aware of this, but GE had some issues with their older aluminum bus loadcenters catching on fire when using the thin Type THQP circuit breakers. The only case I am familiar with is documented with pictures on the Consumer Product Safety Commission website and that case involved a 2-pole 30A THQP circuit breaker. I used to know a former GE sales rep who had switched over to Square D about 15 years ago and I mentioned this to him and he told me that when with GE he had one case where he had to go investigate a similar problem of a panel catching on fire with THQP breakers. I won't even buy a GE light bulb. I would recommend you change out the entire panel to a brand other than GE.
 
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Old 02-21-24, 03:21 PM
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The top 4 breakers on each side need to be full size breakers. You can add the thin breakers below those 4. You will need to get quad breaker to consolidate the space of 2 two pole into 2 spaces. You will need to make sure the quad hits both bus to get the 240 volts.
 
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Old 02-21-24, 04:08 PM
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I have this old GE panel
Unless I miss my guess, that older GE panel has aluminum bus. You probably are not aware of this, but GE had some issues with their older aluminum bus loadcenters catching on fire when using the thin Type THQP circuit breakers. The only case I am familiar with is documented with pictures on the Consumer Product Safety Commission website and that case involved a 2-pole 30A THQP circuit breaker. I used to know a former GE sales rep who had switched over to Square D about 15 years ago and I mentioned this to him and he told me that when with GE he had one case where he had to go investigate a similar problem of a panel catching on fire with THQP breakers. I won't even buy a GE light bulb. I would recommend you change out the entire panel to a brand other than GE.
 
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Old 02-22-24, 08:58 AM
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Thank you so much to both of you for replying - given the information received, coupled with the age of the breaker (and house), it's better that I look at replacing this whole panel box.
 
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Old 02-22-24, 02:20 PM
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Make sure you study up on the current codes. There have been changes in the code requirements since that panel was installed.
 
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Old 02-22-24, 07:31 PM
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Yep, thank you.
 
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Old 02-24-24, 02:23 PM
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current codes
LoL current codes are getting stupid!
With the trash Tamper Resistant Receptacles and AFCI devices!

I think the far bigger risk is exposed prongs from devices that are not fully plugged into a receptacle!
They should make half sheathed prongs like the plugs in the UK are.
 
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Old 02-25-24, 01:54 AM
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There is no such thing as a 240v thin breaker. 240v would have to arrive from 2 legs of the service.
Instead of replacing the entire panel you can install a sub panel next to the existing panel and run your new circuits from there. There are quad breakers.

You say you want to add 8 120volt circuits to this service. What do you plan on using on these circuits?
I ask because we don't know what capacity your present service is and I see some power hungry breakers in there such as 70, 60, 40 just from what I can see in the one picture.

Also, that Siemens 70 amp breaker I believe should not be in a GE panel.

 
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Old 02-25-24, 07:40 AM
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GE does make THQP two-pole breakers that only take up a 1" space. (Example: https://www.homedepot.com/p/GE-Q-Lin...B&gclsrc=aw.ds) The breaker must still straddle the two buses in order to get 240 volts.
 
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Old 02-27-24, 06:01 AM
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There is no such thing as a 240v thin breaker. 240v would have to arrive from 2 legs of the service.
Instead of replacing the entire panel you can install a sub panel next to the existing panel and run your new circuits from there. There are quad breakers.

You say you want to add 8 120volt circuits to this service. What do you plan on using on these circuits?
I ask because we don't know what capacity your present service is and I see some power hungry breakers in there such as 70, 60, 40 just from what I can see in the one picture.

Also, that Siemens 70 amp breaker I believe should not be in a GE panel.
The 8 I would like to add are 6, 15 amp and 2, 20 amp breakers. But now after all this great information, I am not going to try and add these to this main panel, but rather add a sub-panel from this panel. I checked my line coming in and I have 200 amp service from the power company. So, if I am correct, I could have maybe have 80-100 amp going to the sub-panel which would give me a decent amount of expansion?

I did not notice the 70 amp was a Siemens breaker, thank you, I will change that out for a GE breaker.

Thank you so much for your time.
 
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Old 02-27-24, 06:02 AM
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GE does make THQP two-pole breakers that only take up a 1" space. (Example: https://www.homedepot.com/p/GE-Q-Lin...B&gclsrc=aw.ds) The breaker must still straddle the two buses in order to get 240 volts.
Thank you for this, appreciate it.
 
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Old 02-27-24, 06:39 PM
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I could have maybe have 80-100 amp going to the sub-panel which would give me a decent amount of expansion?
Yes, 80-100 amps going to the sub panel would likely work out well.
 
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Old 02-28-24, 08:57 AM
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Hang On - Post #1: Picture of what you are calling your main panel. I can only go by what I see because I can't zoom in on the pic. But I see a red and black insulation conductor going into the main breaker at the top coming from a sheathed cable at the bottom. I can't see other conductors from this sheathed cable and where they go. If this is your main panel then the cable coming in from the bottom should be a SE with two black and a braided aluminum bare, not a black and red going to the breaker.

Do you have a disconnect prior to this panel which is feeding this panel? If so then that is your main panel and this panel is not wired correctly as the neutral and grounds should be separate on this panel and it should be considered a sub panel. Someone else check me on this please.

The 8 I would like to add are 6, 15 amp and 2, 20 amp breakers. But now after all this great information, I am not going to try and add these to this main panel, but rather add a sub-panel from this panel. I checked my line coming in and I have 200 amp service from the power company.
Ummmm: From the power company? Are you referring to the line from the pole to your house connection? Did you call them and ask them what their triplex is rated at? Or are your referring to the cable from the connection at your house down to your meter? If so how did you determine this is 200amps?

How many panels do you have? What is the breaker amp at the first means of disconnect after the meter?

Whether you add a sub panel or not and you want to add 8 breakers - 6 at 15, 2 at 20amp it does not matter. The number of breakers and their amp ratings are meaningless overall. The reason why I say this is because when determining how much demand you want to add to your house adding up the breakers means nothing it is what they will draw in power and when is what matters. You can add 40 - 20amp breakers to your service but it depends on what they will power that matters. Just like receptacles; you can add 30 receptacles to a circuit because receptacles don't pull power if nothing is plugged into them as in breakers, they can be in your panel but if you are not using what they power then they are not consuming power. People ask, "what service do I have and can I add this to my service?" - Many DIYers add up the breakers ratings and determine their service max that way; this is incorrect. The proper way is to do a load calculation and then base the results on that on your present service capacity and then figure out what you want to add to your present service capacity in the way of power consuming devices/appliances and if it will exceed your present capacity.

So again, you can add the 8 breakers but the end result will be determined on what you plan on powering with those 8 breakers compared to your present service capacity.

The utility service can have lines rated much higher going to your house connection that what your present system is rated at so that is not a consideration unless you plan to upgrade past what the utility company service is.

If the picture in post #1 is a panel after another panel/disconnect then the picture in post #1 is a sub panel and not your main panel and it is wired incorrectly - neutrals and grounds should be separate. Is this panel in post #1 the very first panel after the meter or do you have another panel/disconnect before it?

I believe you said you may replace the panel in post #1 - This is not necessary even if you want to add circuits and it may not have the space. Just making space in this panel for a two pole breaker to feed a sub panel after it would be fine.

Just from what I can see you have 40, 70, and 60 breakers. Total capacity is important. I am not saying you are using 170amp of your capacity with these 3 breakers I am just saying it seems you may have some power hungry devices/appliances in your home.



 

Last edited by AFJES; 02-28-24 at 09:13 AM.
 

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