Service Entrance Help Needed

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electrofelon said:
Based on the sound of it, I doubt the available fault current is very high. Are these smallish pad mounts, like 25-50 KVA?
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50 KVA may have more than 10KA available, particularly if you have a really short run of supply conductor to the device in question. Depends on actual impedance of the transformer. Over 50 feet shouldn't be any problem though conductors will have enough resistance to drop the available current at load end.
 
I may have misspoke on the Eaton.
The info shows 10/22.
Eaton's spec sheet shows 10.
Pic of product listing
 

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kwired said:
50 KVA may have more than 10KA available, particularly if you have a really short run of supply conductor to the device in question. Depends on actual impedance of the transformer. Over 50 feet shouldn't be any problem though conductors will have enough resistance to drop the available current at load end.
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On the particular house I'm dealing with now, it's closer to 70 to 80' in length so that may well be the case. My point in it all is that all things considered I'm giving credit to say that all of the calculations were done in the beginning and done correctly and a competent engineer or team of engineers decided that this was the correct action to take and to change it just for the sake of saving money is foolhardy at best. He has access to all the information to do the calculations and make a decision based upon the results but that's not what he's basing his actions on - I could accept that answer based upon those calculations. The correct breakers are now discontinued so in all reality, replacement of the entire unit is now inevitable
 
Tulsa Electrician said:
I may have misspoke on the Eaton.
The info shows 10/22.
Eaton's spec sheet shows 10.
Pic of product listing
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I'm currently awaiting some quotes for a style that interrupts at 65,000. If I can get him, or get the information myself, I'll see if I can make do with a 65 if they are available. No matter what happens regarding this current instance, replacement with new units is inevitable
 
wvelectrician67 said:
I'm currently awaiting some quotes for a style that interrupts at 65,000. If I can get him, or get the information myself, I'll see if I can make do with a 65 if they are available. No matter what happens regarding this current instance, replacement with new units is inevitable
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The need for that high of interrupt rating seems pretty low for the type of application you have, and probably expensive.

Most factory installed main breakers in commonly available "load centers" are only 22-25kA and seldom need to be more than that. Quite often they don't even need to be more than 10kA.
 
kwired said:
The need for that high of interrupt rating seems pretty low for the type of application you have, and probably expensive.

Most factory installed main breakers in commonly available "load centers" are only 22-25kA and seldom need to be more than that. Quite often they don't even need to be more than 10kA.
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The original breakers interrupt at 100. I have replaced 2 of the Q2100 styles because the cases of the breakers had begun to warp from heat. I don't know if it was a problem with the individual breakers or something to do with issues within the house itself but since they have been replaced with the original parts, no further issues have presented themselves. This leaves me inclined to the belief that they need to be replaced with OEM or changed out completely. I have a feeling that the correct part is dimensionally larger in order to compensate for this issue but don't know it as a fact.
 
I should have included more information and this picture if I can get it to upload. The original parts are type EQ-P and manufactured by ITE. The one pictured is a 150A, not in the best of condition and been here longer than I have so you know as much about it as I do. Will upload a data sheet shortly
 

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As you can see, these breakers are obsolete. We have tried unfruitfully to find suitable replacements. Granted, we have not contacted those out there with the $1500 and up price tags because at that point your money is best spent doing a complete upgrade and worry no more
 

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Joethemechanic said:
www.circuitbreakerwarehouse.com

Siemens HQ2100BH Circuit Breaker Reconditioned

Siemens HQ2100BH Circuit Breaker Reconditioned
www.circuitbreakerwarehouse.com

Refurbished 670 bucks. seems crazy but,,,,,,

www.simplybreakers.com

HQ2100BH - Siemens - 100 Amp Motor Starter Overload Relay

HQ2100BH - Siemens 100 Amp 2 Pole 240 Volt Plug-In Motor Starter Overload Relay
www.simplybreakers.com www.simplybreakers.com

400 new
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For this type of breaker refurbishment often means they cleaned and polished the outside of the breaker. There are no servicable parts inside of this breaker.
 
jim dungar said:
For this type of breaker refurbishment often means they cleaned and polished the outside of the breaker. There are no servicable parts inside of this breaker.
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To tell you the truth I've never seen anything that small refurbished. Although that could be because I never looked for one..

But the second link has new for $400.99 Still seems kinda high, but,,,,,
 
Thanks for the recent posts all. My boss has actually been in contact with 2 of them and in the past we have used superbreakers.com with great success but their bottom is now dry for them. I give them a plug here because they really were a very good source for a while.
If it makes anyone involved with this thread feel vindicated, I have heard from a Siemens rep and he agrees with what has been said here. After reading the comments here my boss has decided that we're just going to contact the AHJ and see if they'll allow us to drop to either the 65 or 22-25kA for use. They're the ones who specify these things. But the situation with the AHJ is much like the meter situation - they are not the particular AHJ that they were back then. The same stuff you all deal with. Thanks again for all the insight and advice all of you. We really appreciate it
 
Thanks for the recent posts all. My boss has actually been in contact with 2 of them and in the past we have used superbreakers.com with great success but their bottom is now dry for them. I give them a plug here because they really were a very good source for a while. The trouble with many of these online places is that we order them and 2 weeks later are told that they're unavailable but we keep trying.
If it makes anyone involved with this thread feel vindicated, I have heard from a Siemens rep and he agrees with what has been said here. After reading the comments here my boss has decided that we're just going to contact the AHJ and see if they'll allow us to drop to either the 65 or 22-25kA for use. They're the ones who specify these things. But the situation with the AHJ is much like the meter situation - they are not the particular AHJ that they were back then. The same stuff you all deal with. Thanks again for all the insight and advice all of you. We really appreciate it
 
wvelectrician67 said:
The original breakers interrupt at 100. I have replaced 2 of the Q2100 styles because the cases of the breakers had begun to warp from heat. I don't know if it was a problem with the individual breakers or something to do with issues within the house itself but since they have been replaced with the original parts, no further issues have presented themselves. This leaves me inclined to the belief that they need to be replaced with OEM or changed out completely. I have a feeling that the correct part is dimensionally larger in order to compensate for this issue but don't know it as a fact.
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This heat you mentioned concerns me that the bus it connects to may also been subjected to excessive heat. If so your replacement is not going to last very long, the metal of the bus has lost it's temper and there is nothing you can do to fix that.

This heat has nothing to do with the amp rating of the breaker or the AIC rating. It is plain and simple a result of a poor connection someplace resulting in resistance - which will cause heat. The thing may have only been carrying 20-30 amps while it was heated up. Even if only 5 ohms of resistance there and it is carrying 30 amps 30x5=150 watts of heat given up. That is a lot of heat if confined to a small space like the inside of a breaker. Depending on exactly what/where was going on a bus connecting to it may have been overheated as well.
 
This I understand. The engineer has complained that the breakers in these meters are over engineered and rated far higher than needed. The AHJ is the one who mandated their use and size. We will request that everything be recalculated to see if we can drop to a 65k AIC. I don't hold much hope that we will be able to get it because this place was built in the early 70's when all entrances were only 100 amps. Now that same average is 200 amps. Whatever available current there was before has only increased and I'm hoping to use that idea to get the cooperation I need to at least determine what our real needs are so we can address everything properly.
The meters that overheated have been replaced with new ones since when we had opportunity to and there have been no more issues like them since but we are also trying to determine the problem and head off any other instances before they happen. That is part of the reason for this post was to get a few more ideas to explore in order to correct everything as best as we can. Though the one person is a problem, my immediate boss and I are still going to do what we can to do everything as correctly and completely as we can without interference from the other
 
wvelectrician67 said:
This I understand. The engineer has complained that the breakers in these meters are over engineered and rated far higher than needed. The AHJ is the one who mandated their use and size. We will request that everything be recalculated to see if we can drop to a 65k AIC. I don't hold much hope that we will be able to get it because this place was built in the early 70's when all entrances were only 100 amps. Now that same average is 200 amps. Whatever available current there was before has only increased and I'm hoping to use that idea to get the cooperation I need to at least determine what our real needs are so we can address everything properly.
The meters that overheated have been replaced with new ones since when we had opportunity to and there have been no more issues like them since but we are also trying to determine the problem and head off any other instances before they happen. That is part of the reason for this post was to get a few more ideas to explore in order to correct everything as best as we can. Though the one person is a problem, my immediate boss and I are still going to do what we can to do everything as correctly and completely as we can without interference from the other
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You sure you understand what AIC is? All it basically is is testing the device to be able to withstand a certain level of bolted fault current. IOW a 22kA rated device should be able to interrupt a fault with 22kA of current without being destroyed. The 100 amp trip rating on the handle is what the setting is for sustained overloading conditions and has little to nothing to do with the AIC rating. Available fault current is dependent on source size and impedance, and is reduced some by any resistance/impedance in supply conductors leading to it.

I calculated if you had a 167 KVA transformer which is kind of largest one you commonly will find for single phase, that if it had an impedance of 3%, which is likely the worst case you could find for AIC values, and only had 25 feet of supply 250 aluminum supply conductor to the device in question you would have about 19kA available fault current and would still be fine with 22kA rated device.
 
It's the AIC rating that's killing us because we are trying to do a direct one on one replacement. The 100k, which we have and are now discontinued, cannot be found any more or are priced out of reason. I'm not in the position to be able to make such a change and I'm well aware of it. I am smart enough to know that the physical dimensions of these kinds of things are for a reason. In this case, it most certainly is. I finally found the information that I was looking for and it's published by Siemens. It shows that they only intend for a type QP breaker to be used on branch circuits only and that the style we have we specified for use in metering equipment. That's all I needed. All the about the AIC rating etc just gives me the leeway that I need to go to the people who DO make those decisions and persuade them to my way of seeing things and allow us to use a lower rated one since ostensibly, there is no real loss of protection for anyone/thing. And most importantly to us, breakers that are still being manufactured and thus available. The QP 's did not and do not belong in a metering application and that's from Siemens. That is what I needed and have. The enclosed brochure is very good information for anyone interested.
 

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wvelectrician67 said:
. I finally found the information that I was looking for and it's published by Siemens. It shows that they only intend for a type QP breaker to be used on branch circuits only and that the style we have we specified for use in metering equipment

. The QP 's did not and do not belong in a metering application and that's from Siemens.
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Where are you seeing that information? Every manufacturer uses their standard breakers in their multi position metering assemblies. It's perfectly fine, as long as the AIC rating is appropriate.
 
Siemens Low Voltage Residential Circuit Breakers Miniature Thermal Mag Circuit Breakers - Type QP/MP, 2-Pole, 120/240VAC are Circuit Protection Load Center Mains, Feeders, and Miniature Circuit Breakers. Type: QP/MP Application: Electrical Distribution Standard: UL 489 Voltage Rating: 120/240V Amperage Rating: 100A Trip Range: Thermal Magnetic Interrupt Rating: 10 AIC Number Of Poles: 2P



All comes down to what the available bolted fault current is.

I think any problems in the past are due to a 50 year old installation out in the weather
 
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