Breaker with 90? terminations

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augie47

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Does any manufacturer have on the market a 2000 amp breaker that is listed as suitable for 90? terminations ?
 

Dennis Alwon

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I don't think I ever installed a breaker with more than 3 digits...:lol: Even if the breaker was rated 90C at the terminals the equipment would also need to be rated 90C
 

augie47

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I don't think I ever installed a breaker with more than 3 digits...:lol: Even if the breaker was rated 90C at the terminals the equipment would also need to be rated 90C

as with many of my posts, I should have worded it better :)
 

Dennis Alwon

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I tried searching but got nowhere. The best thing to do is to call the manufacturers and see if one is available. My point before was that the breakers may have 90C lugs but that isn't helpful since the equipment is not rated 90C. I

I have not checked but I understand that some equipment do have 90C lugs but the unit itself is only 75C
 

Dennis Alwon

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This lug, for instance is rated 90C -- that is what the 9 means in the CU9AL

2-250l2_2.jpg
 

templdl

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Wisconsin
Interesting leading question not knowing the rest of the story. Are you implying that you want to use 90, degC rated wire and apply it at 90degC? Even so you must keep one thing in mind that the beaker/device has tested and listed for use with and applied with wire rated at ampacity of 75degC unless otherwise allowed uy the application information.
As such, what is you point?
The only breakers that I know of where 90degC rated wire must be used are 100% rated breakers. When applied according to their instructions in order to achieve their you also must use 90degC rated wire BUT the wire is to be applied at 75degC.
 

jim dungar

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Remember it is the termination not the lug.
Most molded case breakers are listed to UL489, which pretty much prevents them from having terminations which allow conductors to be sized based on the 90C insulation.

Power circuit breakers, like those in drawout switchgear, are listed under different standards and rarely have terminations made directly to the breaker itself. This 'lug landing pad type' of construction is almost always available for use with conductors sized based on 90C.

Enclosure design also impacts the termination rating.
 

templdl

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Remember it is the termination not the lug.
Most molded case breakers are listed to UL489, which pretty much prevents them from having terminations which allow conductors to be sized based on the 90C insulation.

Power circuit breakers, like those in drawout switchgear, are listed under different standards and rarely have terminations made directly to the breaker itself. This 'lug landing pad type' of construction is almost always available for use with conductors sized based on 90C.

Enclosure design also impacts the termination rating.
Would the question now be is this a molded case beaker which to my knowledge 2500a is the largest or a power breaker?
 

augie47

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The question was somewhat generic. A fellow inspector has a job where the conductors would have to be figured at their 90? rating to be large enough. I can't recall the exact size but the range was 2000-3000. We were discussing options and I thought I recalled a breaker that could be employed in that situation'
In hindsight I think A 100% breaker is what was on my mind.
 

jim dungar

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Would the question now be is this a molded case beaker which to my knowledge 2500a is the largest or a power breaker?
Don't forget the enclosure.

I don't believe UL Listed switchboards have terminations for 90C sized conductors, unlike ANSI switchgear which commonly has them.
 

templdl

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Wisconsin
Don't forget the enclosure.

I don't believe UL Listed switchboards have terminations for 90C sized conductors, unlike ANSI switchgear which commonly has them.
Are you referring to a 100% rated breaker?
If I remember correctly when the UL489 breaker is listed for application to 100% rating yes the enclosure must be suitable for application at 100% in addition to the wire be rated 90degC but applied per 75degC.
Also, I agree that ANSI gear is applied by a different set of rules.
 

Smart $

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Ohio
Are you referring to a 100% rated breaker?
If I remember correctly when the UL489 breaker is listed for application to 100% rating yes the enclosure must be suitable for application at 100% in addition to the wire be rated 90degC but applied per 75degC...
That is correct. But continuous loads do not have to be factored at 125%. That could amount to better than the factored value at 90?C ampacity for an all or nearly all continuous load.
 

augie47

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midway thru the thread that (info) all came back to me. I have never encountered a 100% rated and the brain cells were fuzzy. Thanks
 

templdl

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Wisconsin
That is correct. But continuous loads do not have to be factored at 125%. That could amount to better than the factored value at 90?C ampacity for an all or nearly all continuous load.
You are correct when I overlooked adding that note. When sizing the wire it is based upon not 100%+125% as you would with a common 80% rated breaker but 100%+100% which gives one an opportunity to optimize the wire size thus the requirement for 90degC rated wire. Actually, an 80% breaker is no different that a 100% breaker excerpt for the addition of a heat rize test which allows it to be UL listed for a 100% application.
 

kwired

Electron manager
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NE Nebraska
What is voltage?

I no expert in the over 600 volt equipment but think there may be some chance of seeing 90C terminal ratings there.

I am not aware of anything in 600 and below that is 90C though.
 

kingpb

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SE USA as far as you can go
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MV equipment is rated for 90 degree C. But the cable is also rated for 90 and 105 deg C; i.e. MV90 and MV105 cable. Most MV cable manufacturers have quit making MV90 because its easier to just make one type. Although the ampacity is still listed in the NEC. It is applied in the same manner as the same 75 and 90 degree cable, code wise.

You will not find 90 degree rated low voltage equipment, I have discussed this topic with manufacturers and it is too costly for them, and there really is no reason to do it; i.e. no market.
 

Jraef

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Even if the terminations were 90deg, I've never seen a breaker in an enclosure that was tested / listed for 90 degree termination ampacity, even ANSI type.
I think that a stand-alone enclosed hang-it-on-the-wall 100% rated breaker will often have 90C rated terminations, usually Cu only. But... you STILL would have to size the cables for the 75C rating. I can't think of any scenario in which you can SIZE the cables going into any breaker using the 90C column, regardless of the rating of the terminations etc.

Sometimes I wonder if the 90C column should even exist, except as an exception with the rules spelled out as to the ONLY times those ratings can be used. This issue seems to cause more confusion than it's worth.
 

augie47

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Tennessee
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State Electrical Inspector (Retired)
I think that a stand-alone enclosed hang-it-on-the-wall 100% rated breaker will often have 90C rated terminations, usually Cu only. But... you STILL would have to size the cables for the 75C rating. I can't think of any scenario in which you can SIZE the cables going into any breaker using the 90C column, regardless of the rating of the terminations etc.

Sometimes I wonder if the 90C column should even exist, except as an exception with the rules spelled out as to the ONLY times those ratings can be used. This issue seems to cause more confusion than it's worth.

Agree. I have found for those not trained in the Code (and some that are) it can be one of the most "misapplied" sections
 

big john

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Portland, ME
...Sometimes I wonder if the 90C column should even exist, except as an exception with the rules spelled out as to the ONLY times those ratings can be used. This issue seems to cause more confusion than it's worth.
It was already proposed, but the CMP rejected the idea.
Table 310.15(B)(16)
Submitter: Steven R. Musial, II, CJL Engineering
Recommendation: Add the following note at the end of the title block:
(Note: For electrical systems at or below 600 volts, use only the 60?C and 75?C columns per Temperature LimitationsArticle 110.14(C)(1)(a) and (C)(1)(b). The 90?C column applies to electrical systems in excess of 600 volts.)
Substantiation: There is much confusion regarding the 90?C column in this table. Lack of understanding can result in improperly sized conductors in electrical system sat and below 600 volts.
Panel Meeting Action: Reject
Panel Statement: The ampacity of cable must be limited by termination ampacity as stated in 310.15(3)(B). In addition, there may be terminations that are rated above 75 degree C and many large size cables are directly connected to equipment without the use of terminals. The 90 degree C column can be used in some cases for 600 volt systems. The 90 degree C ampacity column can be used for derating purposes or equipment rated 90 degree C.
EDIT: Nevermind, I see the proposal also would've removed the ability to use the 90? for derating which is no bueno.

However, I still don't understand the CMPs response that someone might actually need to termination at 90? rated equipment.
 
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