What's with tandem rated.

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ritelec

ritelec

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Jersey
I've seen so many panels with tandem breakers in it that are not "tandem rated". Never see or saw signs of a problem with any installed.

With the exception of not being "code compliant" because the panel was not tested and or approved for a tandem,
What's the difference if you stab a 40,60,or 100 amp breaker at that spot compared to stabbing a 15/15 or 20/20?

Just wondering. Thankyou.
 
Probably not an issue at all. Remember prior to 2008 code we were limited to 40 circuits per panel. This was one means of trying to maintain compliance with that section of the NEC.
 
If this is what I think that you are asking on the NP compare the number of spaces with the number of circuits. If there are more circuits allowed than the number of spaces then there are spaces that allow for the use of tandem breakers.
 
templdl said:
If this is what I think that you are asking on the NP compare the number of spaces with the number of circuits. If there are more circuits allowed than the number of spaces then there are spaces that allow for the use of tandem breakers.
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Thought the panel had to be rated for a tandem?

??? So your saying that a 100a 20circuit (no tandem ratings) could get filled with tandems as long as it doesn't go over 42 circuits??

Works for me...
 
Dennis Alwon said:
That is not the case.
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I agree........but again, if it's not rated could you throw 2 or three tandems in there.

The good book says no. but as mentioned, why not? (a 60 -2 pole (even a couple) could get injected??)

So I'll follow the guide lines.......and continue with my curiosity and "tandem rated".

Thanks gents.
 
ritelec said:
Thought the panel had to be rated for a tandem?

??? So your saying that a 100a 20circuit (no tandem ratings) could get filled with tandems as long as it doesn't go over 42 circuits??

Works for me...
Click to expand...

When a panel's NP shows 20ckts how does that equal 42 is that with refernce to the largest panel with the most number of circuits? If so I believe that a 42ckt panle is not available that tandem breakers can be intalled.
Remember ckts are different than spaces. Spaces are either 1" or 3/4". As such full size breakers are either 1" as with the Eaton BR and the SqD Homeline for example and 3/4" for the Eaton C-H and the SqD QO. There a various combinations of 20, 24, and 30ckt panels that have provisions for tandem breakers for up to 40ckts total.
As an example there a Eaton BR panels that are:
12sp-20ckt which means (12) 1" breakers or (4) 1" and (20) tandems
10 20 which means (10) 1" or a combinations of 1" up to (20) tandems and no 1"
12 24
16 20
16 24
20 40
24 40
30 40
The panels where spaces equal circuits will not allow tandems to be installed because they have a reject feature in each space as those panels that permit part of the spaces for use with tandem breakers such as a 12/20 panel where 4 spaces will not allow the installation of tandem breakers.

Personally I have found no difference in the actual construction of a 16sp/16ckt panel and a 16sp/20ckt. which are the same size except that the 16/16 rejects the use of tandem breakers which makes it a marketing thing.
 
Along with tandem breakers, there are Quad breakers for some panels.

Picture a standard two pole breaker. The outside poles would be single pole 15 A or 20 A.

The inside handles would be tied together & could be two pole 20 A, 25A, 30A etc
 
John120/240 said:
Along with tandem breakers, there are Quad breakers for some panels.

Picture a standard two pole breaker. The outside poles would be single pole 15 A or 20 A.

The inside handles would be tied together & could be two pole 20 A, 25A, 30A etc
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Yes, and they can be very confusing when you order them, which pole where, the rating of each pole in what location as it relates to the cataolg part number.
 
I am most familiar with the QO breaker panels, but I am pretty sure that they all have rejection methods so you can not put a tandem where it was not designed to be installed. QO does have non CTL tandem breakers that are intended as replacements only for older panels that did not use the rejection features, they are also more expensive than a tandem with the rejection feature. If you were to install a new panel and fill it with these breakers you would spend more than if you used a larger panel to start with.
 
There was a time when you could modify the old ITE breaker twins so that they would fit in the regular slots. Code compliant --NO- but I have seen it done many times. I just left a job the other day where the 40 cir CH panel had 50 circuit breakers in it.
 
The Tandem breaker is also refered to as a piggyback.
?QO tandem circuit breakers in combinations (15 A to 30 A)
Cutler Hammer type 'CHT' Piggy Back Circuit Breaker in combinations (15A to 20A). CH doesn't seem to have a 30a pole.
Remember that the load for the 2 poles must be feed from a ingle stab of the bus which is the limiting factor. This of a simple 50a 1p of 2p breaker where the stab needs to supple 50a. Now use a 20/20 tandem where that same stab must supply 40a.

In a quick check I was not able to verify if either panel differentiated between the number of spaces and circuits and if either had any reject features. As such you would have to take the time to define that
 
templdl said:
Remember that the load for the 2 poles must be feed from a ingle stab of the bus which is the limiting factor. This of a simple 50a 1p of 2p breaker where the stab needs to supple 50a. Now use a 20/20 tandem where that same stab must supply 40a.
Click to expand...

I am aware of this, I also realize that most of the time the bus is designed to accept a 100 or even a 125 amp breaker, so the rejection feature IMO has little to do with how many amps may be supplied through one space on the bus.
 
kwired said:
I am most familiar with the QO breaker panels, but I am pretty sure that they all have rejection methods so you can not put a tandem where it was not designed to be installed. QO does have non CTL tandem breakers that are intended as replacements only for older panels that did not use the rejection features, they are also more expensive than a tandem with the rejection feature. If you were to install a new panel and fill it with these breakers you would spend more than if you used a larger panel to start with.
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I have a Sq D 40 circuit panel. I have removed several tandems I had installed over the years and have since installed a sub panel.
I'm curious and will look into it.....but from what I remember there was no problem adding the older tandem switches side by side horizontal type, or the newer switch over switch vertical type.


http://www.structuretech1.com/2012/02/tandem-circuit-breakers/


Haven't thought about this in a while, remember the federals......their tandems where 2 really thin singlepoles that clipped into their weird buss design. Sometimes they clicked in nicely (as there singlepoles)
and other times you would think (hoped) you got it in right (along with their singlepoles) and you would walk away cringing.....
 
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kwired said:
I am aware of this, I also realize that most of the time the bus is designed to accept a 100 or even a 125 amp breaker, so the rejection feature IMO has little to do with how many amps may be supplied through one space on the bus.
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Great, then I know that you are aware that when you install a 100 or 125A breaker can you another one just like it in the space across from it or any breaker for that matter? If not then the space across it is useless. Would that then mean that each space has a max. capacity of 60a or a total of 120a should (2) 60a breakers mounted across from one another?

Also, regarding the rejection features, believe me that it's all about marketing and how they want to UL list and label it to address certain price points in the market.
 
templdl said:
Great, then I know that you are aware that when you install a 100 or 125A breaker can you another one just like it in the space across from it or any breaker for that matter? If not then the space across it is useless. Would that then mean that each space has a max. capacity of 60a or a total of 120a should (2) 60a breakers mounted across from one another?

Also, regarding the rejection features, believe me that it's all about marketing and how they want to UL list and label it to address certain price points in the market.
Click to expand...
If not marked otherwise you can put maximum sized breakers on opposite sides on the same bus fingers. Square D QO is what I am most familiar with and as far as I know you could put 125 amp breakers directly across each other on the same bus fingers, in majority of the panels. The 6 and 8 space versions with aluminum bus are an exception - and are limited to 70 amp per connection, but those also by design do not have another breaker on opposite side anyway.
 
kwired said:
and are limited to 70 amp per connection, but those also by design do not have another breaker on opposite side anyway.
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Don't understanD?


here's a 100......should it not fit and still put even another opposite it?


http://www.ebay.com/itm/NIB-SQUARE-...ps=63&clkid=1606897842123095987#ht_500wt_1413

I was looking for a type of breaker that goes across like the 100 main breaker (across 4 poles (2) you know what I mean).

But find a plethora of 2 pole under over brks that can still allow for plugins on the opposite side.???

Edumacate me.................thank you.
Rich
 
ritelec said:
Don't understanD?


here's a 100......should it not fit and still put even another opposite it?


http://www.ebay.com/itm/NIB-SQUARE-...ps=63&clkid=1606897842123095987#ht_500wt_1413

I was looking for a type of breaker that goes across like the 100 main breaker (across 4 poles (2) you know what I mean).

But find a plethora of 2 pole under over brks that can still allow for plugins on the opposite side.???

Edumacate me.................thank you.
Rich
Click to expand...

A panel like this one will not have breakers across from each other and is what I was talking about. This panel is also only rated for 70 amp max branch breakers, but I think the version with copper buss is rated for 100 amp branch breaker.

QO816L100S.jpg
 
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