Mini breakers or new panel?

[deluks]

I ran into the problem of not having enogh spaces in a panel for a new circuit. I was just wondering if it would be a good idea to use a mini breaker, instead of changing out the panel that would have more spaces? What risks do I run if I put in a mini breaker?

 

[Dexie123]

You need to make sure that the panel is listed to accept tandem breakers and the accept the breakers that you are planning to install.

 

[wireman71]

Mini breakers! If it's a normal resi panel it will more than likely accept them.

 

[JohnJ0906]

If the panel is not listed for tandems, you do not

necessarily​

need to change it to a larger, you can also add a sub-panel next to it, or in another convenient location.

 

[jim dungar]

Mini breakers! If it's a normal resi panel it will more than likely accept them.

Not true. For example, most Square D QO and HOM 24, 30, and 40 circuit panels are not rated for tandems.

 

[brantmacga]

Not true. For example, most Square D QO and HOM 24, 30, and 40 circuit panels are not rated for tandems.

if that's true, then why is a 30 space homeline listed for 40 circuits?

In a HOM3040M(or L)200, the 40 means 40 circuits.



EDIT---

This Square D document says the single phase QO & Homeline loadcenters are acceptable for use with tandem circuit breakers.

 

[rexowner]

if that's true, then why is a 30 space homeline listed for 40 circuits?

One could argue because he said "most" not "all".

The 24-place panels are generally 125-amp panels with
only full-size breakers, and the 40 place panels are
full-size breakers. I can't incontrovertibly
prove it, but WRT the 30 space models,
I was told by my usual supply house that the 30-space
panels which only take 30 full-size breakers, e.g.
the HOM30L200TC are more popular than
the the 30/40's e.g. the HOM3040L200TC, which
surprised me a little. Another anecdotal piece of
data is HD Supply, which seems to target GCs more
than ECs, stocks the 30-place, 30-circuit models, and
they stock so little I would believe they would only
stock the most popular SKUs.

So, it's probably true to say "most".

 

[jim dungar]

if that's true, then why is a 30 space homeline listed for 40 circuits?

I did not all I said most were not rated for them.

On page 1-6 of the current Digest, there are 15 main breaker QO panels 24 circuit or larger not rated for tandems versus 3 listed for them, on page 1-14 there are 9 main breaker HOM panels not rated for tandems versus 7 rated for them

If the Square D panel does not include two sets of numbers it is not rated for tandems.

 

[brantmacga]

One could argue because he said "most" not "all".

The 24-place panels are generally 125-amp panels with
only full-size breakers, and the 40 place panels are
full-size breakers. I can't incontrovertibly
prove it, but WRT the 30 space models,
I was told by my usual supply house that the 30-space
panels which only take 30 full-size breakers, e.g.
the HOM30L200TC are more popular than
the the 30/40's e.g. the HOM3040L200TC, which
surprised me a little. Another anecdotal piece of
data is HD Supply, which seems to target GCs more
than ECs, stocks the 30-place, 30-circuit models, and
they stock so little I would believe they would only
stock the most popular SKUs.

So, it's probably true to say "most".

I just went back to the site and found this PDF. In the QO model, tandems are accecptable only in the 10k AIC rated single phase loadcenters. In the homeline model, tandems are acceptable in all single phase models rated for 125A or more, the smallest being the 24 space. There may be some things they are not accepted in, but they weren't in this document.

 

[brantmacga]

I did not all I said most were not rated for them.

On page 1-6 of the current Digest, there are 15 main breaker QO panels 24 circuit or larger not rated for tandems versus 3 listed for them, on page 1-14 there are 9 main breaker HOM panels not rated for tandems versus 7 rated for them

If the Square D panel does not include two sets of numbers it is not rated for tandems.

Don't have a panic attack Jim. Wireman said "if its a normal resi panel" it'll most likely accept them. According to the "Residential Products Catalog" .pdf link I posted, he's right.

 

[LarryFine]

What risks do I run if I put in a mini breaker?

I have no problem using tandems as long as it's applied properly, as outlined above. I prefer to use them on the lowest-rated circuits I can.

 

[rexowner]

I just went back to the site and found this PDF. In the QO model, tandems are accecptable only in the 10k AIC rated single phase loadcenters. In the homeline model, tandems are acceptable in all single phase models rated for 125A or more, the smallest being the 24 space. There may be some things they are not accepted in, but they weren't in this document.

QO124L125G is in that document (and in my garage) and
does not accept tandems.

HOM30L200TC is in that document and does not accept
tandems. I was installing one today and the GC goes
and buys tandems, which I told him not to do because
it doesn't accept them, and of course they don't fit.

Read, e.g. Page 7 of the document. There is a
column called "Max Number of Tandem CBs". There
are many products with a zero in the column, i.e. they
don't accept tandem breakers, including all the 24 and
40 place loadcenters and most of the 30-place products.

 

[brantmacga]

QO124L125G is in that document (and in my garage) and
does not accept tandems.

HOM30L200TC is in that document and does not accept
tandems. I was installing one today and the GC goes
and buys tandems, which I told him not to do because
it doesn't accept them, and of course they don't fit.

Read, e.g. Page 7 of the document. There is a
column called "Max Number of Tandem CBs". There
are many products with a zero in the column, i.e. they
don't accept tandem breakers, including all the 24 and
40 place loadcenters and most of the 30-place products.

The HOM30L200 is identical to the HOM3040L200; I think square D lets you order them to specifically not take tandems. It looks like for every model number that doesn't accecpt tandemns, there is an identical model that does accept tandems. I suppose it is up to the contractor to decide which one he wants to use.

 

[480sparky]

The HOM30L200 is identical to the HOM3040L200; I think square D lets you order them to specifically not take tandems. It looks like for every model number that doesn't accecpt tandemns, there is an identical model that does accept tandems. I suppose it is up to the contractor to decide which one he wants to use.

The difference will be in the bus bars at the bottom of the panel. The 30-circuit panel will not have 'V's notched into the bus bars to allow tandems. On the 40-circ panel, the bottom 5 bars will have the V notched into them.

 

[jim dungar]

Don't have a panic attack Jim. Wireman said "if its a normal resi panel" it'll most likely accept them. According to the "Residential Products Catalog" .pdf link I posted, he's right.

It is not a panic attack it is a statement of fact.
Considering all Square D loadcenters, 24 circuit and larger with a main breaker, you have less than a 30% chance of the panel being rated for use with tandem breakers.

And I do know Square D products, I was a field sales engineer for them from 78-89.

 

[LarryFine]

Why bother discussing the norm, the average, the typical, the whatever? :-? What matters is whether the panel in question accepts tandems, not everyone else's.

 

[brantmacga]

The difference will be in the bus bars at the bottom of the panel. The 30-circuit panel will not have 'V's notched into the bus bars to allow tandems. On the 40-circ panel, the bottom 5 bars will have the V notched into them.

Yes I know this. I should have stated they were "almost identical". :smile:

It is not a panic attack it is a statement of fact.
Considering all Square D loadcenters, 24 circuit and larger with a main breaker, you have less than a 30% chance of the panel being rated for use with tandem breakers.

And I do know Square D products, I was a field sales engineer for them from 78-89.

Jim, the post that started all this "if its a normal resi panel. . . tandems should fit". Square D makes a lot of panels that don't take tandems, but I've yet to purchase one at my supply house, and I've never needed to install a tandem in an existing Square D panel that wouldn't take it. According to the .pdf I posted, unless I'm reading over something, MOST homeline panels accept tandems; 63% of them (excluding 42ct panels). Anyhow, I'm just stating what I know to be true, which is the same as what wireman said. If its a normal residential panel, you'll most likely be able to install a tandem breaker. Its also probably due to the fact that supply houses aren't stocking oddball panel sku's like the ones that don't take tandems; i should clarify that none of the supply houses I buy from stock those. But I think its true in a lot of places.

 

[inspector 102]

Right or wrong, I just installed two tandem breakers in a QO 200 amp load center. The load center was installed 24 years ago and I needed 2 additional spaces for a hot tub circuit. The tandem breaker wer QO1515 to replace the 15 amp OCD's that were there. Cost- 42.00 per tandem. Should have installed a sub-panel and been prepared for the next change. Hindsight is always 20/20.

 

[brantmacga]

Right or wrong, I just installed two tandem breakers in a QO 200 amp load center. The load center was installed 24 years ago and I needed 2 additional spaces for a hot tub circuit. The tandem breaker wer QO1515 to replace the 15 amp OCD's that were there. Cost- 42.00 per tandem. Should have installed a sub-panel and been prepared for the next change. Hindsight is always 20/20.

$42 per tandem? Did you have them gold plated or something? For homelines I pay less than $10 and QO's are less than $20.

 

[C3PO]

Right or wrong, I just installed two tandem breakers in a QO 200 amp load center. The load center was installed 24 years ago and I needed 2 additional spaces for a hot tub circuit. The tandem breaker wer QO1515 to replace the 15 amp OCD's that were there. Cost- 42.00 per tandem. Should have installed a sub-panel and been prepared for the next change. Hindsight is always 20/20.

The QO1515 will fit anywhere on any QO panel but is only listed to be used in old panels that are not CTL listed panels. The QO style tandems for CTL panels is a QOT1515 and will only fit in certain spots and only on panels that are supposed to accept tandems.