Bad to load a panel with THQP (thin) breakers? Replacing small FPE load center?

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Flot

Member
Location
Florida
I recently got a bit of a lecture for a previous job where an interior load center (FPE) had been replaced with a GE loaded with thin THQP breakers. As I understand it, this is inline for the design specs for the box (12/24), so his comment caught me off guard. Box is a TLM1212CCUG4K

His argument was that the job was improperly done because while ripping out the old panel, a physically larger panel with 1" breakers should have been used.

Now, the downside to that approach - every run of incoming metal conduit would have had to be cut, to relocate the box higher, or half the original circuits spliced, to allow them reach the new breaker locations which would be physically farther away.

Just looking for the preferred solution here. Smaller/tighter box, or tweaking all of the existing runs? This is a common situation in 1960s south florida homes, main panel outside with 1-6 circuits and small inside subpanel with 15-20 circuits.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
I recently got a bit of a lecture for a previous job where an interior load center (FPE) had been replaced with a GE loaded with thin THQP breakers. As I understand it, this is inline for the design specs for the box (12/24), so his comment caught me off guard. Box is a TLM1212CCUG4K

His argument was that the job was improperly done because while ripping out the old panel, a physically larger panel with 1" breakers should have been used.

Now, the downside to that approach - every run of incoming metal conduit would have had to be cut, to relocate the box higher, or half the original circuits spliced, to allow them reach the new breaker locations which would be physically farther away.

Just looking for the preferred solution here. Smaller/tighter box, or tweaking all of the existing runs? This is a common situation in 1960s south florida homes, main panel outside with 1-6 circuits and small inside subpanel with 15-20 circuits.

Is this your boss or an inspector giving you the what for? It doesn't sound like someone who's trying to get it done more quickly and cheaply, so I'm going to guess the latter. As long as the installation meets code, I'd listen politely and do it the same way again next time. :D
 

Flot

Member
Location
Florida
Didn't mean to mislead - my house, interior box replaced 3-5 years ago, I'm getting quotes to do the outside one now. I'm also in the process of buying again and will need both boxes replaced - insurance companies are cracking down and the going rate is $1k-2k.

Just trying to make sure I know who is doing it right, south florida full of hacks. To put that in perspective, 2 of the last 4 homes I looked with "upgraded" electric still had the neutral bond bar installed in the inside subpanel.
 
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user 100

Senior Member
Location
texas
I recently got a bit of a lecture for a previous job where an interior load center (FPE) had been replaced with a GE loaded with thin THQP breakers. As I understand it, this is inline for the design specs for the box (12/24), so his comment caught me off guard. Box is a TLM1212CCUG4K

His argument was that the job was improperly done because while ripping out the old panel, a physically larger panel with 1" breakers should have been used.

Now, the downside to that approach - every run of incoming metal conduit would have had to be cut, to relocate the box higher, or half the original circuits spliced, to allow them reach the new breaker locations which would be physically farther away.

Just looking for the preferred solution here. Smaller/tighter box, or tweaking all of the existing runs? This is a common situation in 1960s south florida homes, main panel outside with 1-6 circuits and small inside subpanel with 15-20 circuits.

Is this an EC doing this? If so he is trying to upsell, by convincing you need something you may not- like that nice new more pricey Square d.:happyyes:

The EC, or whatever may have a hang up w/ those thin breakers and a lot do- the ge wafers are considered to low end, the bus connection seems a little puny and he may believe incorrectly that the panel can be loaded w/ more breakers than listed for, etc.. but forget all that.

I would trust that cheap GE more than the FPE that was there originally.:) Like comparing a Pinto to an Acura.
 
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MMT77002

Member
Location
Houston, TX USA
Are you kidding?

Are you kidding?

I recently got a bit of a lecture for a previous job where an interior load center (FPE) had been replaced with a GE loaded with thin THQP breakers. As I understand it, this is inline for the design specs for the box (12/24), so his comment caught me off guard. Box is a TLM1212CCUG4K

His argument was that the job was improperly done because while ripping out the old panel, a physically larger panel with 1" breakers should have been used.

Now, the downside to that approach - every run of incoming metal conduit would have had to be cut, to relocate the box higher, or half the original circuits spliced, to allow them reach the new breaker locations which would be physically farther away.

Just looking for the preferred solution here. Smaller/tighter box, or tweaking all of the existing runs? This is a common situation in 1960s south florida homes, main panel outside with 1-6 circuits and small inside subpanel with 15-20 circuits.

1in or 1/2 in breakers all must pass thermal and short circuit tests per UL 489. The load enter is UL labeled for 12/24 circuits which means the assembly passed thermal and short circuit testing to the UL standards. These tests are done at maximum ampacity at 40C.

I don't know who said this, I would point out the UL label on the loadcenter and ask why UL approved and listed it. The only caveat to this is that all wiring must be 75C insulation.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
I noticed that the OP's model # had a 12/12 in it. Maybe the inspector called him out on it as being only 12 circuit CTL panel so he could not "technically" be using twins/mini's whatever you want to call them with that panel (even though you must have used non-conforming breakers) that would stab on that panel configuration.
 

MMT77002

Member
Location
Houston, TX USA
1212 doesn't mean Only 12 circuits

1212 doesn't mean Only 12 circuits

I noticed that the OP's model # had a 12/12 in it. Maybe the inspector called him out on it as being only 12 circuit CTL panel so he could not "technically" be using twins/mini's whatever you want to call them with that panel (even though you must have used non-conforming breakers) that would stab on that panel configuration.

If you search this catalog number you will find the 12/24 description. The 1212 reference is only catalog data.
 

Smart $

Esteemed Member
Location
Ohio
If you search this catalog number you will find the 12/24 description. The 1212 reference is only catalog data.
Actually its base model, TLM1212CCU, is listed as a 14/24... as an MLO. When converted to main breaker it uses the top two right 1" spaces for the main breaker, then it's a 12/22. Only 1" breakers can be used in the two 1" spaces across from the main breaker. This is per GE Catalog...
https://www.geindustrial.com/sites/...log/buylog/01_BuyLog2013_LoadCtrCircBreak.pdf
 

kwired

Electron manager
Location
NE Nebraska
The problem that will reduce the demand for twin/tandem/half size breakers in residential work is the requirement to use AFCI's, which only fit in a full size slot so far. Outside of that issue nothing wrong with what OP has described.
 

peter d

Senior Member
Location
New England
Just trying to make sure I know who is doing it right, south florida full of hacks

I've spent a fair bit of time in SW Florida and I can attest to that. I've looked at many new homes under construction as well as many existing homes and it seemed like decent workmanship was the exception and not the rule.
 

user 100

Senior Member
Location
texas
I don't know who said this, I would point out the UL label on the loadcenter and ask why UL approved and listed it. The only caveat to this is that all wiring must be 75C insulation.

Where can I find this rule?

I think there might be some confusion about the breaker rating- the rating on these is 60/75- which means that you can use 60 degree or 75 degree conductors, but the thing is is that if 75c conductors are to be connected to these brkrs and used at full ampacity, the breaker can't have anything around it- unless the panel/service equipment/other components are also rated for 75c.

Modern nm is rated for 90c and gets terminated to brkrs with this same rating all the time- of course the 90c nm is automatically derated to 60c, and it is this reduction which makes it acceptable for use w/ these brkrs.

..... nothing wrong with what OP has described.

:thumbsup:
 
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Smart $

Esteemed Member
Location
Ohio
I think there might be some confusion about the breaker rating- the rating on these is 60/75- which means that you can use 60 degree or 75 degree conductors, but the thing is is that if 75c conductors are to be connected to these brkrs and used at full ampacity, the breaker can't have anything around it- unless the panel/service equipment/other components are also rated for 75c.
...
To somewhat quell the confusion, from UL Whitebook...
CIRCUIT BREAKERS (DHJR)
USE
This category covers circuit breakers which, unless otherwise noted, are of
the manually operable, air break type, providing automatic overcurrent protection.
PRODUCT MARKINGS AND RATINGS
These circuit breakers and circuit breaker enclosures are intended for use
with copper conductors unless marked to indicate which terminals are suitable
for use with aluminum conductors. Such markings are independent of
any marking on terminal connectors and are located on a wiring diagram or
another readily visible location.
1. Circuit breaker enclosures are marked to indicate the temperature rating
of all field installed conductors.
2. Circuit breakers with a current rating of 125 A or less are marked as
being suitable for 60°C, 75°C only or 60/75°C rated conductors. It is
acceptable to use conductors with a higher insulation rating, if the
ampacity is based on the conductor temperature rating marked on the
breaker.
3. Circuit breakers rated 125 A or less and marked suitable for use with
75°C rated conductors are intended for field use with 75°C rated conductors
at full 75°C ampacity only when the circuit breaker is installed
in a circuit breaker enclosure or individually mounted in an industrial
control panel with no other component next to it, unless the end-use
equipment (panelboard, switchboard, service equipment, power outlet,
etc.) is also marked suitable for use with conductors rated 75°C.
4. A circuit breaker with a current rating of more than 125 A is suitable
for use with conductors rated 75°C.
5. Circuit breakers intended for continuous operation at 100% of rated
current may be marked to be connected with 90°C rated wire with the
size based on 75°C ampacity.
A suitable marking is required in a circuit breaker enclosure, whether or
not terminals are mounted therein, if it is intended that the breaker to be
mounted therein is to be used with aluminum wire.
 

kwired

Electron manager
Location
NE Nebraska
To somewhat quell the confusion, from UL Whitebook...
For the most part if the breaker/panelboard in question is 20 years old or less, (some instances maybe even older) everything is likely rated 75C and this is only an issue with older equipment.
 
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