1000 Amp Non-adjustable trip Breaker

[raider1]

Are there any 1000 ampere or above, Non-adjustable trip circuit breakers with the ability to disable the instantaneous trip portion commercial available?

This question is in regards to 240.87 (2011 NEC)

Chris

 

[zog]

Sure, molded case or power breaker?

 

[jim dungar]

I believe the UL 489 standard for 'thermal-magnetic' molded case breaker requires that they have some type of inherent 'instantaneous' protection, or else they could not be used with switchboards and panels that only have 3-cylce fault ratings.

 

[raider1]

Sure, molded case or power breaker?

Either one. What I am trying to ascertain is whether there are 1000 ampere or higher breakers available that are non-adjustable type but could have the instantaneous trip function disabled for selectivity.

As currently stated 240.87 applies to all circuit breakers without an instantaneous trip.

Chris

 

[raider1]

I believe the UL 489 standard for 'thermal-magnetic' molded case breaker requires that they have some type of inherent 'instantaneous' protection, or else they could not be used with switchboards and panels that only have 3-cylce fault ratings.

What about power circuit breakers or insulated case circuit breakers?

Chris

 

[zog]

What about power circuit breakers or insulated case circuit breakers?

Chris

INST trips are an option on most trip units, and is a defeatable option on some others.

 

[zog]

I believe the UL 489 standard for 'thermal-magnetic' molded case breaker requires that they have some type of inherent 'instantaneous' protection, or else they could not be used with switchboards and panels that only have 3-cylce fault ratings.

The MCCB's that I am familiar with that have an "INST off" feature still have a trip with no delay that occurs at the ST withstand rating. So that meets the UL requirement, and seems to still apply to 240.87. (?) I think.

 

[jim dungar]

The MCCB's that I am familiar with that have an "INST off" feature still have a trip with no delay that occurs at the ST withstand rating. So that meets the UL requirement, and seems to still apply to 240.87. (?) I think.

Yes it does.

If the device is listed to UL489, regardless of its construction, it will always have some Instantaneous protection, even if the device setting is "OFF".
This inherent protection often plays havoc with selective coordination requirements in the "700" articles of the NEC.

Power breakers (e.g. built to ANSI C37 or UL 1066) have actual Short Time withstand ratings and therefore do not need inherent Instantaneous protection.

 

[raider1]

So would it be safe to say that I could purchase a non-adjustable trip power circuit breaker without instantaneous trip?

Chris

 

[zog]

So would it be safe to say that I could purchase a non-adjustable trip power circuit breaker without instantaneous trip?

Chris

Never heard of a non adjustable trip power CB

 

[raider1]

Never heard of a non adjustable trip power CB

That is what I am trying to ascertain whether or not there are any non-adjustable trip breakers (Power, MCCB, or other type) available that do not contain an instantaneous trip function or a instantaneous trip function that can be overridden for selectivity.

Chris

 

[zog]

That is what I am trying to ascertain whether or not there are any non-adjustable trip breakers (Power, MCCB, or other type) available that do not contain an instantaneous trip function or a instantaneous trip function that can be overridden for selectivity.

Chris

Not sure what you mean by non adjustable trip breakers? That is like a residential breaker. I thought Jim and I answered the question clearly, now you are confusing me.

 

[jim dungar]

So would it be safe to say that I could purchase a non-adjustable trip power circuit breaker without instantaneous trip?

Not at this time.
And, most likely never.

 

[G._S._Ohm]

Here's one search
http://www.google.com/webhp?hl=en&t...188606f417ebf4&bpcl=40096503&biw=1039&bih=749
depending on how many quoted phrases Google allows, there may be many more combinations.

 

[raider1]

Sorry for the confusion.

Yes you both answered my question. I got confused myself.

I went back and re-read the section that I am researching and found that I read the section wrong.:ashamed::ashamed::ashamed:

Thank you for the input gentleman I really appreciate it.

I had read "adjustable trip breaker" instead of "adjustable instantaneous trip function".

Chris

 

[raider1]

Man I feel like an idiot.:ashamed:

How did I read that so wrong.:slaphead:

You every have one of those days.............

Chris

 

[zog]

Yep, we all do. Glad you figured it out. So, why are you asking? Have a specific issue or just wondering?

 

[raider1]

I was researcing information in regards to a comment made to CMP 10 in regards to 240.87

I had read the wording in the comment as "Adjustable trip circuit breaker" where the comment actually read "Circuit breaker where the adjustable instantaneous trip is disengaged".

Thanks again for the help.

Chris