408.36 maximum number of OCPDs - 42

[teufelhounden91]

Hi all, in 408.36 it mentions that the maximum number of OCPD's that can be installed in a cabinet is 42 under exception 2.

My 1st question:

Does a single pole double throw breaker count as one OCPD or two?

The exception states a 2pole or 3pole breaker counts as 2 devices or 3 devices respectively, but not single pole breakers with 2 handles.

Also I know they make panels with Mains that have provisions for 60 breakers.

My 2nd question: Is the 42 OCPD rule only for panels that have a remote main? Can you have more than 42 OCPDs if you have a MB in the panel?




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[ron]

The language changed in later code cycles. What year is adopted in your jurisdiction?

Essentially, a 2 pole breaker is 2 of the 42, if you follow a code cycle with that still as a requirement.

 

[don_resqcapt19]

...
Does a single pole double throw breaker count as one OCPD or two?
...

I have never even heard of a single pole double throw breaker. What would it be used for?

 

[charlie b]

Does a single pole double throw breaker count as one OCPD or two?

I don’t know what that would be. I know what a “single pole, double throw switch” is, but I haven’t heard that phrase used in connection with a breaker. What do you mean by this?

The exception states a 2pole or 3pole breaker counts as 2 devices or 3 devices respectively, but not single pole breakers with 2 handles.

Here again, I don’t think such a thing exists. Or perhaps you are not clearly naming or describing what you mean. If you mean one of those “half width” breakers for which two breakers can fit in the space normally occupied by one breaker, and for which both of the two breakers are connected to the same phase, then that thing counts as two overcurrent devices, for the purposes of this rule.

Also I know they make panels with Mains that have provisions for 60 breakers. My 2nd question: Is the 42 OCPD rule only for panels that have a remote main? Can you have more than 42 OCPDs if you have a MB in the panel?

They make panels with provisions for 88 breakers. They are not required to have main breakers, if there is a feeder breaker serving the panel from the upstream panel.

My 2nd question: Is the 42 OCPD rule only for panels that have a remote main? Can you have more than 42 OCPDs if you have a MB in the panel?

No, the 42 OCPD rule applies to the circumstances that are described in Exception 2. The basic rule is that the panel must be protected by a SINGLE OCPD. The exception allows for protection by a set of two OCPDs, but then it imposes the 42 circuit limit.

 

[jumper]

I have never even heard of a single pole double throw breaker.

I wonder if that is what OP is calling a tandem/piggyback breaker?

 

[don_resqcapt19]

I wonder if that is what OP is calling a tandem/piggyback breaker?

Good point.....
If that is the case, then the number of that type of breaker is based on the listing and the instructions.

It doesn't matter that the code has removed the 42 circuit limitation if the manufacture in the instructions has limited the number of tandem/piggyback breakers. Some manufacturers limit not only the number of those breaker, but also the locations in the panel where they can be installed.

 

[teufelhounden91]

I guess I should have called it a tandem 20 - a single pole breaker with 2 handles


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[GoldDigger]

I guess I should have called it a tandem 20 - a single pole breaker with 2 handles

There is the difference in usage.
It fits into one space in the panel and is one physical device, but most everybody would still call it two poles and specifically two single pole breakers as it can feed two separate branch circuits.