twin circuit breaker

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Trouyano

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when their is no more room in a panel and you want to add more circuits, is their anything in the nec that prohibits use of twins or the amount of twins you can add as long as the panel is not being overloaded? Or should you add a sub panel and add circuits?
 
Trouyano said:
when their is no more room in a panel and you want to add more circuits, is their anything in the nec that prohibits use of twins or the amount of twins you can add as long as the panel is not being overloaded? Or should you add a sub panel and add circuits?

You can add up to 40 circuits for a residential panel since I believe that is the largest they make. A twin breaker may only be added if the panel is designed for them.

Some panels are designed for twins but only in the lower half of the panel while others will let you add to all space. For instance a 20-40 panel has 20 spaces but will accept 40 if you use twins. The panel directory and labels should have that info available.
 
sparky_magoo said:
The panel usually sez how many ckt.'s are allowed. This number is usually twice the number of spaces allowed.


I would say most panels that allow twins or tandems are 30/40, but I have seen my fair share of 20/40. I thought the circuit limit was 42, not 40 and the only panel I had seen that would take more (w/o some serious modification :rolleyes: ) were the QOs. They may have changed, but their bus bar would allow a tandem anywhere on it, thus allowing 60 circuits. But i think they changed the design on the "snap bar" that the hook on the tandem breaker would only fit in specifed spots. Off topic, but does QO make a 2-pole tandem like HomeLine and other brands??
 
360Youth said:
I would say most panels that allow twins or tandems are 30/40, but I have seen my fair share of 20/40. I thought the circuit limit was 42, not 40 and the only panel I had seen that would take more (w/o some serious modification :rolleyes: ) were the QOs. They may have changed, but their bus bar would allow a tandem anywhere on it, thus allowing 60 circuits. But i think they changed the design on the "snap bar" that the hook on the tandem breaker would only fit in specifed spots. Off topic, but does QO make a 2-pole tandem like HomeLine and other brands??
Yes their are tandem QO's. The only problem with adding tandems is the load now going to exceed your neutral rating?
 
ceb said:
Yes their are tandem QO's. The only problem with adding tandems is the load now going to exceed your neutral rating?

Adding circuits is going to add to your load, period. Add to many and you will adding a new service, too. :smile:
 
mdshunk said:
Okay, now you're gonna need to explain that one.
OK Marc, give me a break I had a brain fart. I have seen a case where some one used 14-3 on a tandem as a MWBC to feed recpt. and lights in a room and then feed a new addition recp. and lights. The net. was carrying the full load not the unbalanced as a MWBC would
 
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