Square D panels confuse me as to where/how many tandems are allowed - can someone help me with this? TIA. BTW, it did say 24 circuits max.
1 Like
Were you able to read the model # on the nameplate?
No, but I know I saw 24 circuits max. I can’t ever tell from the diagram with the 2 lined breakers and single line breakers - it’s very confusing. Can you make heads or tails out of it (1st pic)?
Not really that’s why I asked about a model number.
If the panel/ledger has 20 spaces, and 24 are the max, wouldn’t that suggest only a few spots allowed for tandems?
Typically if any are allowed it is the end opposite the main breaker or lugs. To get to 24 circuits the bottom 4 on each side need to be tandems which agrees with the label. Look for the boxes with 2 lines.
The Model # on the cover is HOM20M100C. According to Square D that is a 100 amps, 20 circuit only panel.
I count 12 OCPD’s and 20 circuits.
Missed 4 circuits. That panel has 24.
1 Like
Morning, Jim.
Hope this post finds you well.
I do not think so. I still get a 20 active circuit count on 12 breakers.
Am I missing something?
Are you counting the tandems and two pole breakers as two?
To answer the thread, I never gave Tandem breaker allowance unless they did weekly choirs on schedule. I think it was 25 cents back then. Nowadays, I do not know what would be an reasonable allowance.
In my count I am referring to ‘molded case breakers’ and circuits in use.
Hope that helps.
1 Like
I agree. A two pole counts as 2 circuits so does a tandem circuit breaker.
2 Likes
Correct me if I am wrong, Please.
Double pole breakers can have 2 circuits connected by single neutral.
Double pole breakers may/can count as 2 circuits. Metal clips bonding toggles. Equipment OCPD.
Yes. A tandem breaker is designed to allow two 120-volt circuits to be fit into a single slot in the circuit breaker box. They are normally installed in situations where the breaker box is already full with no available slots for additional circuit breakers.
As to the double pole breakers. I suspect the 25 amp, 30 amp and 40 amp breakers are for equipment leaving the 20 amp that could be for lighting circuit/s. Did you see any 20 amp outlets/receptacles?
PS: You could do a neutral count to identify circuit count.
A neutral count will not consider a straight 240 load that does not utilize a neutral i.e. water heater.
It would be easier if the panels were labeled with a pole count.
1 Like
Not sure if this answers your question but when determining the maximum number of circuit breakers in a panel a single pole counts as 1 CB, a 2 pole counts as 2 CB’s, and a 3 pole counts as 3 CB’s.
408.54 Maximum Number of Overcurrent Devices. A panelboard shall be provided with physical means to prevent the installation of more overcurrent devices than that number for which the panelboard was designed, rated, and listed. For the purposes of this section, a 2-pole circuit breaker or fusible switch shall be considered two overcurrent devices; a 3-pole circuit breaker or fusible switch shall be considered three overcurrent devices.
1 Like
Afternoon, Robert. Thanks for the reply. I understand your point but the point I am trying to make is the distribution panel label says 20 circuits max not posable circuit breakers max. I concur the possibility of 24 circuits can be meet. My reply is, to do a circuit count you would have to count and identify circuit conductors that can carry and return current to the source.
You need to count the number of poles in the panel. The panel pictured has 24 poles worth. The directory is only reflecting the number of full size poles that will fit. The wiring diagram will show if tandems are allowed or the model number like 3040.