Service AIC ratings

Status
Not open for further replies.
iwire said:
Let me ask this.

How do you get around 110.3(B) and the RMC or EMT labeling on the minnis?
Click to expand...


Are straps required to be listed for PVC conduit to use them? What about cable ties, are they listed for conduit support? According to 352.30 the fastening method is required to permit thermal expansion and contraction. Seems like the double nutted mini would have that covered.
 
infinity said:
Are straps required to be listed for PVC conduit to use them?
Click to expand...

I am not sure, but I do know most EMT clips have both UL and EMT stamped on them which puts us right back to 110.3(B) 'listed equipment shall be used as intended'

To me this is the same issue as using an MC clamp for NM, it works but is not listed for that use.
 
The problem with supporting PVC is that the support has to let it move to accommodate the expansion and contraction. The use of the same types of clamps or straps that we use for metal conduit will not permit the required movement.
352.30 Securing and Supporting.
PVC conduit shall be installed as a complete system as provided in 300.18 and shall be fastened so that movement from thermal expansion or contraction is permitted. PVC conduit shall be securely fastened and supported in accordance with 352.30(A) and (B) or permitted to be unsupported in accordance with 352.30(C).
Click to expand...
 
don_resqcapt19 said:
The problem with supporting PVC is that the support has to let it move to accommodate the expansion and contraction. The use of the same types of clamps or straps that we use for metal conduit will not permit the required movement.
Click to expand...


Certainly the slightly loose double nutted mini that Ken used will accomplish this. Now whether or not the strap is required to be listed for that purpose that's another story. :rolleyes:
 
infinity said:
Certainly the slightly loose double nutted mini that Ken used will accomplish this. Now whether or not the strap is required to be listed for that purpose that's another story. :rolleyes:
Click to expand...

But that minni is a listed to be used with EMT and or RMC, how are you getting around that other then just ignoring it?
 
infinity said:
Hmmm, guess there's no way around that huh. :rolleyes:
Click to expand...

I was poking around Carlons site trying to find an answer, some of the photos in a cut sheet show PVC on minnis. :grin:

All I know is the inspectors I have worked with in my area expect PVC clips to be used with PVC. :smile:
 
Square D QOB breakers do have series ratings with Class J fuses. Look at the label inside of your panelboard.

Charlie did a good job of detailing the issue of series ratings of circuit breakers. My only comment is that the use of the phrase "modern circuit breaker" makes it sound like dynamic impedance is a new phenomena. The better phrase would be "molded case circuit breaker". In general, unless a circuit breaker is a large power/industrial breaker or it is more than 50 years old it will be covered by 240/86(A).
 
jim dungar said:
Square D QOB breakers do have series ratings with Class J fuses. Look at the label inside of your panelboard.

Charlie did a good job of detailing the issue of series ratings of circuit breakers. My only comment is that the use of the phrase "modern circuit breaker" makes it sound like dynamic impedance is a new phenomena. The better phrase would be "molded case circuit breaker". In general, unless a circuit breaker is a large power/industrial breaker or it is more than 50 years old it will be covered by 240/86(A).
Click to expand...

According to Bussmans charts , under NQOD panelboards

http://www.bussmann.com/pdf/1572c3b7-882c-4bdc-b520-0ff0123439a5..pdf

This is the fuse I will need ?? BUT its a 600 volt fuse and very costly about $135 each

http://www.cooperbussmann.com/ProductInfo.aspx?productID=5599
 
Ken In NJ said:
. . . I also sent Charlie a PM .. hopefully he will be back online line and see it :)
Click to expand...
I do not normally post anything in the forum that I have said in a PM. However, in this case, the question is the same and the answer reveals nothing of a private nature so I am breaking my rule. My response:

"It will be necessary to verify that the listed combination does exist and that your installation is marked in accordance with 110.22(C). In my opinion, you should be working with your engineer to verify that the system will work as intended under all fault conditions. Even though I helped write the requirements in 240.86(A), I am not an engineer and can not take you are further. Also, several of the guys that participate in the forum (including some moderators), are engineers and can give you more help than I can. Personally, I feel like this is the best site with the most knowledgeable people on the Internet. :smile:"
 
iwire said:
I am sure he will stop by when he is online. :smile:
Click to expand...
Yep, I was getting ready for a gathering tomorrow. We will have three tables in to play Bridge and we are getting the house and food ready. Needless to say, I will be absent again shortly and not be back until tomorrow evening. :grin:
 
ken, at this point you have no choice, get the engineer involved, it is his or her design, save yourself the headache
 
mpd said:
ken, at this point you have no choice, get the engineer involved, it is his or her design, save yourself the headache
Click to expand...

Yep .. that is what I am gonna do, I was just hoping to solve the problem before I speak to him HOPEFULLY Monday ..

The Job is in NJ and the engineer is in Kentucky.. I hope it just gets done asap .. its one of those rush, rush I need my store open kinda jobs .. I hate to be the one to hold progress up :cool:
 
Panel info

Panel info

I use Cutler-Hammer products and on their panels they seem to have series rating based upon combination testing on the cover. Ofcourse you have to put the flash sticker on the dead front but whatever. If you still have the paper work for your panel look for series rating. Also if you can't find anything ask your sale guy at your parts house a good sales guy know all about the series rating of the panels he sells. Also read your electrical engineer's line diagram see if it says full rating or series rating. I posted a OP in Ele Calc and Engineering on 10-26 regarding MIN AIC might be helpful. Also, I know that JJNL fuses I used were rated at 100k maybe different fuse could higher series rating without you incurring cost of fully rating panel. If all else fails call engineer.
 
Ken In NJ said:
Yep .. that is what I am gonna do, I was just hoping to solve the problem before I speak to him HOPEFULLY Monday ..

The Job is in NJ and the engineer is in Kentucky.. I hope it just gets done asap .. its one of those rush, rush I need my store open kinda jobs .. I hate to be the one to hold progress up :cool:
Click to expand...


If I was the engineer, the day of the inspection I would have requested a letter from an engineer for the resolve of the installation. I myself am not an engineer, that is the reason for a letter with his stamp on it. The letter should describe the resolution, including any calculations that may be necessary.
 
Status
Not open for further replies.
Top