mstrlucky74
Senior Member
- Location
- NJ
If it says 400AF & 300AT. The "F" is the frame and the "T" is trip? Which one indicated the size of the breaker? The frame I assume? For laboring purpsose I'm curious. Thanks.
DRAW OUT BREAKER
- Thread starter mstrlucky74
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zog
Senior Member
- Location
- Charlotte, NC
400A breaker, just set up for 300A trip. Could be 300A CT's, CT tap, rating plug, etc...
mstrlucky74
Senior Member
- Location
- NJ
zog
Senior Member
- Location
- Charlotte, NC
The frame is the frame size, depends on what the context of your question is. I don't get what laboring is.
400A is pretty small for a draw out breaker.
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I've done plenty of take offs and your reply Zog that it is a 400a frame size with a 300a trip unit is correct and belaboring the subject any longer certainly isn't going to change that. When you have a 400af you are indicating that it most likely has a 400af with an interchangeable trip unit which could be changed in the field up to a 400at. The specifier could have specified a 600af with a 300at if they wanted to have the ability to upsize the circuit up to 600a
Should the specifier want a sealed breaker they may have specifier wanted a sealed breaker with a 300at they mat specify it as a NIT (non interchangeable trip) an IT for inerchangable trip.
But to intergect draw out into the mix is a non issue.
A one line would illustrate drawouts.
zog
Senior Member
- Location
- Charlotte, NC
The title of this thread is "Draw out breaker", so I assumed it was draw out 
mstrlucky74
Senior Member
- Location
- NJ
It is a drawout breaker.
- Location
- San Francisco Bay Area, CA, USA
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- Electrical Engineer
I don't think I have ever seen a 400AF draw out breaker in North American (ANSI) Metal Clad equipment with Power Circuit Breakers or Insulated Case Circuit Breakers, which is what I think Zog is thinking of.
But it's somewhat common in low voltage IEC distribution equipment. It's essentially an accessory added to the rear of a molded case circuit breaker (MCCB), in which case a 400AF would be very common. I haven't seen many people use them here in the US though.
The title of this thread is "Draw out breaker", so I assumed it was draw out
Zog, I know that this isn't the first rodeo for you nor I we just didn't fall off of the turnip truck. My concern is his knowledge of the differences of these devices and the advantages an disadvantages of each.
As far as laboring I can take a very big guess that he is quoting a job and trying to determine the cost of labor wouldn't you thing? I would venture to guess that there is a good chance that this is a job that isn't a good match for him.
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- Placerville, CA, USA
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- Retired PV System Designer
"Laboring under a misconception"?
That's a positive maybe.
kingpb
Senior Member
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- SE USA as far as you can go
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- Engineer, Registered
Eaton - CH makes a 400A frame
Do you sincerely believe that the OP understands what a draw out breaker is? If it has been listed on a BOM it is with almost all certainty a frame size and trip unit. Normally it will be fotpr an MCCBwith an IT which provide for the option of chance the trip to a 400at at a later date. Other wise the may specfy a a NIT breaker with a sealed trip such an C-H LBB3300 which would be a 400af with a sealed 300at trip unit.
Yes, on the long shot the it is a draw out ACB I would be looking for an actual spec and one line where the one line would show a draw out breaker and the specifications would include the features an options required.
As such a person who experience a reviewing BOMs should be able to quickly determine the requirement.
Oh, by the way, did you know that there is a draw out option for a 400a frame MCCB? A very expensive option which includes both moving and stationary parts.
There are also switchboards the MCCBs are mounted individually in their individual barriered compartments on use bus run backs to cunnect with bus as well as individually mounted MCCBs that have a plug on option using tulip connects and the basic stabs and jaws.
Yes, when I looked at the OP which the limited information as provided and no specifaction or one line provided 400af and 300at is a 400A frame breaker with a 300A trip is it installed. If it were to be more complicated than that there would have been a spec and one line included.
weressl
Esteemed Member
That is correct, a 400AF breaker is electrically and thermally designed to carry 400A continuously. The 300AT is indicative that it is equipped with a trip unit that will limit that continuous current to 300A. The trip unit most likely will also add some additional trip characteristics. The 300AT is indicative the Long time trip. Various Short time, Instantaneous ranges, Ground fault and delay adjustments are available to shape the tripping time/current curve of the breaker.
Good point. A basic old school thermal magnetic breaker would be limited to a fixed thermal, in this case 300a, and adjustable magnetic of 5-10 x the 300a or 1500-3000a. When supplied with an electronic trip all of the bells and whistles as you described are available. These features provide an means for coordination with other devices with similar features as well and integral ground fault which also has the ability to coordinate with devices with similar features.
kingpb
Senior Member
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- SE USA as far as you can go
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- Engineer, Registered
Not quite understanding the need for the dissertation or all the speculation. I simply was letting Jraef know that there is at least one manufacturer that does make a 400AF draw out breaker.
Carry on......................
- Location
- San Francisco Bay Area, CA, USA
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- Electrical Engineer
Just out of curiosity, what series? I couldn't find anything under 800AF in current products.
zog
Senior Member
- Location
- Charlotte, NC
Nothing current, looking on my shelf I have some FP-25's, ITE KB/KC's, Westinghouse DA, and Allis Chalmer LA-25A's that are all 400A draw out. Newest one of those was made in the late 50's.
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
It was the Eaton SPB which could take the digitrip unit.
However, not so sure they make it anymore, but it was a 400AF with a drawout mechanism.
However, not so sure they make it anymore, but it was a 400AF with a drawout mechanism.
weressl
Esteemed Member
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