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-   -   QO panel no tandems? (http://www.diychatroom.com/f18/qo-panel-no-tandems-203723/)

cj133 07-18-2014 08:44 AM

QO panel no tandems?
 
So, I'm almost out of places to add circuits and I decided to look into what options I have. According to the label inside my panel all 20 locations do not accept tandems.

Anyone know why this is? I realize knowing why won't change anything but I'm curious what the difference between a 20A tandem and a 40A single is.


https://scontent-a-lga.xx.fbcdn.net/...55772976_o.jpg



The one double breaker in the picture is from a stove circuit, which is what is wire nutted off on the left side so those are my last 2 locations open. The other wires that are disconnected on the right side are from a dryer circuit. In 2011 I installed natural gas in the house and converted the appliances as well. Part of me thinks I should move these into a sub panel and reconnect them for possible future use, though it seems most people think that's a waste.

So, two questions.

I'm thinking my only option if I want more is to add a sub panel. What is the largest sub panel I should add to this? Part of me says to ditch the stove and dryer circuits and re-use the 40A breaker from the stove to run the sub panel.

My panel is missing the screw to bond the neutrals to the box. In place of it I have a piece of 6 AWG copper going from a neutral terminal to one of the grounding bars but I would like to make things right. What type of screw do I need for this? I'm guessing some zinc plated machine screw from Homer isn't correct.

cj133 07-18-2014 10:31 AM

Actually nix the 40A B.S.

Seems like the smart move is to buy a 100A subpanel and pony up for a new 100A breaker.

The price difference between a 60A and 100A QO breaker is interesting. $16 vs $56.

brric 07-18-2014 02:13 PM

Tandems are available for QO panels although the panel may not be listed for their use.
http://images.search.yahoo.com/image...mdsmll&fr=ipad

cj133 07-18-2014 02:19 PM

Quote:

Originally Posted by brric (Post 1377217)
Tandems are available for QO panels although the panel may not be listed for their use.
http://images.search.yahoo.com/image...mdsmll&fr=ipad


Yeah, that's the issue.
My panel won't accept the hook they have.

Any idea why this is? What is the difference between a tandem 20 and a 40A single as far as the panel is concerned?

Oso954 07-18-2014 02:49 PM

Quote:

What is the difference between a tandem 20 and a 40A single as far as the panel is concerned?
It is not a comparison of a single position, it has to do with limiting the total current in the panel. You don't want someone replacing all the 15 or 20 amp breakers with tandem 20's.

40 amp singles (120V) are not commonly used in residential wiring. The 40 amp stove breaker that you talked about in your OP should be a 2 pole (240V).

brric 07-18-2014 02:51 PM

Quote:

Originally Posted by cj133 (Post 1377223)
Yeah, that's the issue.
My panel won't accept the hook they have.

Any idea why this is? What is the difference between a tandem 20 and a 40A single as far as the panel is concerned?

Non-CTL breakers won't have the hook.

cj133 07-18-2014 02:59 PM

Quote:

Originally Posted by Oso954 (Post 1377235)
It is not a comparison of a single position, it has to do with limiting the total current in the panel. You don't want someone replacing all the 15 or 20 amp breakers with tandem 20's.

40 amp singles (120V) are not commonly used in residential wiring. The 40 amp stove breaker that you talked about in your OP should be a 2 pole (240V).


Yep it is,
However I assumed you could get single pole 40A ones. We all know what happens when we assume. :no:

Looks like 30A is the highest standard single pole QO I can find.

cj133 07-18-2014 03:05 PM

Quote:

Originally Posted by brric (Post 1377238)
Non-CTL breakers won't have the hook.


I've heard about those.
What is the reason for the CTL feature?

brric 07-18-2014 03:07 PM

Circuit limiting.

40 amp single pole breakers are readily available.

cj133 07-18-2014 03:15 PM

Quote:

Originally Posted by brric (Post 1377250)
Circuit limiting.

40 amp single pole breakers are readily available.

Interesting.

Why does Square D not allow standard tandems in my panel, but does allow them in others?

My only guess is physical room for wires and or heat dissipation. If that's the case isn't going around that dangerous?

Currently considering a 6POS 12 circuit QO panel and a few feet of 6-3 copper wire. Seems like the better route, no?

brric 07-18-2014 03:30 PM

Quote:

Originally Posted by cj133 (Post 1377254)
Interesting.

Why does Square D not allow standard tandems in my panel, but does allow them in others?

My only guess is physical room for wires and or heat dissipation. If that's the case isn't going around that dangerous?

Currently considering a 6POS 12 circuit QO panel and a few feet of 6-3 copper wire. Seems like the better route, no?

Go for it.

Jim Port 07-18-2014 08:59 PM

They did not pay for the panel to be listed for tandems. Simple economics.

Non-ctl breakers are for replacement use only. Panels have been CTL rated for many years.

Jump-start 07-18-2014 08:59 PM

You could get away with none CTL tandems, but I agree this panel isn't listed for that. I know, I find it silly that panel makers and NEC cod panels put such hard restrictions on panel circuits.

Sub panel would be the complaint route.

micromind 07-18-2014 09:59 PM

The Square D non-CTL tandem breakers do have a rejection feature that will not allow them to be used with panels that are not designed for tandems.

They'll fit some panels but not all.

micromind 07-18-2014 10:03 PM

Quote:

Originally Posted by cj133 (Post 1377242)
Yep it is,
However I assumed you could get single pole 40A ones. We all know what happens when we assume. :no:

Looks like 30A is the highest standard single pole QO I can find.

Square D makes single pole QOs in 10, 15, 20, 25, 30, 35, 40, 45, 50, 60 and 70 amp.


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