Grounding probes: Hazard or helpful?
- Thread starter Edward Smith
- Start date
L98-Z
New member
Chances are he never will. If it makes you feel any better, he could be 100% correct, but his inability to debate these topics would have everyone on here believing you're correct. Of course, I think the majority of people here support your view anyways, so this really isn't an issue.
BeanAnimal
Premium Member
That was an insult right there Steve! One only has to look back a few pages to see you calling me, Stu and others inexperienced fools. You do this EVERY time somebody points out an error in your statements. You post a bunch of nonsense and then say it is hard to take the "mambo jambo" seruiously.Bean sorry man, some times I just cant take your stuff seriouslyanyway, ok I will answer seriously, and I didn't insult you,
So lets get back on subject:
Yes
I predict you are going to try and slither out of this one... So that everybody else here is clear. You answers was clearly NO as evidenced by your previous posts on the subject.
Frank, the switch gear AIC rating can exceed the Fault Current rating of the service. The equipment MUST be rated HIGHER than the calculated available fault current for the service. You statement (shown again below) illustrates that you do not understand AIC ratings.
You said
You do not appear to understand what the AIC rating means or what the code requires. You don't want customer equipment failing due to a fault, that is crazy. The exact opposite is true. The entire premise of an AIC rating is to ensure that the customer equipment can handle the worst case fault current that can be delivered by the service. I am baffled why a guy who touts credentials such as your would say something like that.
Again, this is all very basic electrical theory and Ohm's law and your comments indicate that you may not have a full grasp of it, you basically got it 100% backwards.
So what is the truth?
The AIC rating is determined by the Available Fault Current that the service can provide. If you took a shorting bar and jumpered over the supply transformer secondary, the amount of current available at the service equipment would be the Available Fault Current. In other words, the Available Fault Current is dictated by the impedance and power rating of the transformer and service drop. The service equipment should have an AIC rating higher than the AFC rating. For most homes the available fault current is in the 10kA range, so 15kAIC rated equipment is acceptable, but 65kAIC rated equipment would be even better.
So Frank, ANYTHING DOWN STREAM of the transformer SHOULD have an AIC rating higher than the fault current that that transformer can provide. The further downstream you get, the lower the AIC needs to be because of resistance in the line.
You can use 22kAIC breakers in a 10kAIC panel. You can use a 65kAIC panel on a service that is rated at 22kA of fault current. You CAN NOT do the opposite, and that is EXACTLY what you are contending.
Again don't take my word for it. Here is a paper that clearly covers everything you need to know regarding TVSS devices and AIC.
http://ieeexplore.ieee.org/iel5/11204/36065/01708878.pdf
Heres a teaser from the above article:
As detailed in Article 285.6, the code allows SPDs to
be used at points within the electrical distribution system
where the short circuit current rating of the SPD is greater
than that of the system, but not where the short circuit current
of the system is greater than that of the SPD SCCR...
...As an example of a correct application, assume that
an SPD is going to be installed on the power distribution
system of a facility at a branch panel location. At this point in
the power distribution system, the available fault current
capability is 42,000 A. The available fault current at this
location, or any other within the power distribution system of
the facility, must be determined through a fault current analysis
by the supervising engineer. Assume that this SPD is
placed behind a circuit breaker with an SCCR of 42,000 A,
shown as in Figure 1. In addition, the SPD has obtained a
SCCR of 65,000 A. In this example, the SCCR of the SPD is
coordinated with that of the facility’s power distribution
system, resulting in correct and coordinated application. In
fact, as long as the SCCR of the SPD is equal to or exceeds
the point of application within the power distribution and the
preceding over-current protective device, the SCCR of the
SPD is correctly coordinated.
As an example of an incorrect application, assume
that a SPD has obtained a SCCR of 25,000 A from UL.
Assume that this particular SPD was placed behind a circuit
breaker with an SCCR of 65,000 A, as shown in Fig. 1.
Additionally, assume that the maximum SCCR available at
this particular location on the power distribution system is
42,000 A. As with the previous example, the supervising
engineer is responsible for determining the available fault
current at this particular point within the power distribution
system of the facility. In this particular example, the SPD is
incorrectly applied. Because the SPD has obtained an SCCR
rating of only 25,000 A, it might not be capable of withstanding
an interrupt current of 42,000 A.
Like I said, you got it 100% backwards. What bothers me is that this is basic stuff (as are many of the things you have clearly stumbled over), yet you continue to promote yourself as an authority on the subject and belittle those who are clearly well informed. I just don't get it.
Why not try admitting your errors and respecting the others who share knowledge in the field. We all learn every day Steve.
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funman1
Active member
<a href=showthread.php?s=&postid=13406812#post13406812 target=_blank>Originally posted</a> by Young Frankenstein
You are teaching electricity from stuff printed from RC ? Way to go there
Only things that are acompanied by a solid reference (NEC, NFPA, etc...)
So I guess that excludes your posts
Young Frankenstein
New member
Hi ya Michael good to see you again.
Bean and funman, in theory yes its not a problem wiring higher AIC rating equipment in any place, after all it is stronger than the power company's transformer feeding your place. My argument is that, and this is not a copy paste from a website.
1) THE SERVICE PLANER FROM THE LOCAL POWER COMPANY WILL NOT APPROVE HIGHER AIC RATING.
2) THE BEC WILL REJECT THE PLANS FOR CONSTRUCTION.
Can an individual wire something higher without approval yes.
Will it be safe, probably yes.
Is it legal NO.
If you agree please state so.
Bean and funman, in theory yes its not a problem wiring higher AIC rating equipment in any place, after all it is stronger than the power company's transformer feeding your place. My argument is that, and this is not a copy paste from a website.
1) THE SERVICE PLANER FROM THE LOCAL POWER COMPANY WILL NOT APPROVE HIGHER AIC RATING.
2) THE BEC WILL REJECT THE PLANS FOR CONSTRUCTION.
Can an individual wire something higher without approval yes.
Will it be safe, probably yes.
Is it legal NO.
If you agree please state so.
Young Frankenstein
New member
And my answer (BEC will reject any electrical drawings for residential use that are higher than the power company's AIC) that why we get the "Fault Current Letter" from the power company, and thats why BEC asks for it.Period. Dot. END And there you go again, reapiting myself.
Young Frankenstein
New member
1. General
The Customer should consult FPL at an early stage to verify availability of service (section II.C)
and to determine the FPL designated point of delivery (section III.B). Contact with FPL should
be made before the purchase of equipment and its installation. This FPL approval is not a
substitute for inspection and approval by the local electrical inspection authority. FPL assumes
no responsibility for the Customer's wiring installation. Upon request, FPL will inform the
Customer of available short circuit currents.
http://www.fpl.com/doingbusiness/builder/pdf/Ess4SvcMtrConnect.pdf
The Customer should consult FPL at an early stage to verify availability of service (section II.C)
and to determine the FPL designated point of delivery (section III.B). Contact with FPL should
be made before the purchase of equipment and its installation. This FPL approval is not a
substitute for inspection and approval by the local electrical inspection authority. FPL assumes
no responsibility for the Customer's wiring installation. Upon request, FPL will inform the
Customer of available short circuit currents.
http://www.fpl.com/doingbusiness/builder/pdf/Ess4SvcMtrConnect.pdf
BeanAnimal
Premium Member
You are 100% wrong Frank. I posted proof showing so. The article lists the relevant sections of the NEC code.
However, that is not really what is at issue, I (we) have easily proved you to be wrong and used reputable sources to back it up.
Here is the bigger issue. You said:
The only thing that I see being a problem is the AIC rating, Power company's HV transformers are usually 65Ka and in residential designs all the equipment is supposed to be 22-15Ka so that it can fail before The power company's transformer
Nothing could be further from the truth. That single statement pretty indicates that you have no idea what an AIC rating is or what it means.
BeanAnimal
Premium Member
What you are saying makes obsoletely no sense. The service equipment MUST meet or EXCEED the Fault Current calculation provided by the POCO or engineer. You have it 100% backwards, just like you did the relay contacts and the ground probe safety issues.
BeanAnimal
Premium Member
Nice try Steve but that does nothing to help your incorrect position on this matter. All that says is that Fault Current must be determined and equipment must be installed in consideration of those fault currents. Last I checked, that is exactly what we were talking about. The problem is that you have very clearly illustrated that you don't know what the ratings mean or how they are used to size service equipment.
Remember you said: The only thing that I see being a problem is the AIC rating, Power company's HV transformers are usually 65Ka and in residential designs all the equipment is supposed to be 22-15Ka so that it can fail before The power company's transformer I am not going to let you wriggle away from this and change the subject.
You followed it by saying: Can an individual wire something higher without approval yes.
Will it be safe, probably yes.
Is it legal NO.
You clearly do not understand. You still have it backwards. The service equipment is MOST CERTAINLY allowed to exceed the Available Fault Current rating of the service feeding the equipment. Read the article I posted again Steve, then go to your NEC and read the cited code sections. You have it backwards.
Are we really going to head down this path now? You know, the one were you post things that don't prove your point but relate somehow to the subjet?
You appear to be in way over your head in many of these discussion and instead of backing down, you turn them into disasters so that nobody can follow them. It is not fair to the people who are here trying to learn something.
Stu asked a very good question regarding TVSS devices. Your response was incorrect on both counts and I have kindly shown proof from many sources as to why. Instead of leaving it at that, here we are once again. You insisting that your experience proves you to be correct and the NEC and Engineers are all wrong.
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stugray
Premium Member
YFrank,
ONE of the first times you post a link to backup your claims, and NOWHERE in that document does it list AIC or "Ampere Interrupting Capacity".
So just what point are you trying to make? That "The Customer should consult FPL "????
NO-WHERE does it mention ANYTHING about the current topic.
EXCEPT the line that you failed to quote:
"No resistor or reactor or other similar fault current limiting device shall be installed in the neutral or the phase conductors of the service entrance without the approval of FPL."
We are NOT suggesting that, so it is NOT applicable.
However ( Thanks for the Link ):
It DOES State that:
"It shall be able to successfully interrupt the maximum fault current available at its location"
AND
"As stated previously, FPL recommends that the service entrance have more capacity than the minimum required by the NEC."
Notice the MORE CAPACITY statement........ You just proved Beans argument AGAIN.
That statement means that "the Hardware IN THE residence SHOULD HAVE greater capacity then the supply ( transformer )"
NOW you are in my realm of expertise.... I DO REQUIREMENTS!
The above statement says "FPL recommends" That means OPTIONAL.
SO they are saying "you SHOULD HAVE greater capacity in the residence than the transformer can supply" but it is NOT a requirement.
Did I mention that "Notice the MORE CAPACITY statement........ You just proved Beans argument AGAIN."
Stu
ONE of the first times you post a link to backup your claims, and NOWHERE in that document does it list AIC or "Ampere Interrupting Capacity".
So just what point are you trying to make? That "The Customer should consult FPL "????
NO-WHERE does it mention ANYTHING about the current topic.
EXCEPT the line that you failed to quote:
"No resistor or reactor or other similar fault current limiting device shall be installed in the neutral or the phase conductors of the service entrance without the approval of FPL."
We are NOT suggesting that, so it is NOT applicable.
However ( Thanks for the Link ):
It DOES State that:
"It shall be able to successfully interrupt the maximum fault current available at its location"
AND
"As stated previously, FPL recommends that the service entrance have more capacity than the minimum required by the NEC."
Notice the MORE CAPACITY statement........ You just proved Beans argument AGAIN.
That statement means that "the Hardware IN THE residence SHOULD HAVE greater capacity then the supply ( transformer )"
NOW you are in my realm of expertise.... I DO REQUIREMENTS!
The above statement says "FPL recommends" That means OPTIONAL.
SO they are saying "you SHOULD HAVE greater capacity in the residence than the transformer can supply" but it is NOT a requirement.
Did I mention that "Notice the MORE CAPACITY statement........ You just proved Beans argument AGAIN."
Stu
BeanAnimal
Premium Member
Stu, FWIW, that article I posted was authored by some of the guys over at Cooper Bussman. It is very well written by authorities in the overcurrent protection field. It is one of those "keep this handy" documents becuase it says so much, so clearly, in so few words. It is the kind of thing that guys like Funman wish they had on every topic they teach.
Young Frankenstein
New member
This is the kind of statements you should avoid.
BA says.
Nothing could be further from the truth. That single statement pretty indicates that you have no idea what an AIC rating is or what it means.
have some respect.
Now heres the Green Dragon for ya.
BA says.
Nothing could be further from the truth. That single statement pretty indicates that you have no idea what an AIC rating is or what it means.
have some respect.
Now heres the Green Dragon for ya.
Young Frankenstein
New member
Stu thanks for doing your best to keep this conversation normal, and I also will reply with kindness.
I could be wrong, you could be wrong. I have access to unlimited sources (engineers, FPL service planers, inspectors, even the Miami chief electrical inspector (his name is also Stu by the way Stu Bazerman ) I will call and ask, You will get an honest answer back.
I could be wrong, you could be wrong. I have access to unlimited sources (engineers, FPL service planers, inspectors, even the Miami chief electrical inspector (his name is also Stu by the way Stu Bazerman
) I will call and ask, You will get an honest answer back.
Young Frankenstein
New member
BA ruddly says :
You appear to be in way over your head in many of these discussion and instead of backing down
YF answers :
Speak for yourself, most of the information you have posted in the past is copy paste from Wikepedia.com show off , heres another dragon.
You appear to be in way over your head in many of these discussion and instead of backing down
YF answers :
Speak for yourself, most of the information you have posted in the past is copy paste from Wikepedia.com show off , heres another dragon.
Young Frankenstein
New member
In conclusion Bean I think you are a great person and have helped many people with given answers. But your methods have pushed away many professionals from also wanting to participate and help others. I think you should mellow out a bit, chill out, relax, be kind, look at the green dragon how relaxed he is smoking his pipe, ok?
BeanAnimal
Premium Member
I have posted links to articles and industry manufacturers that show irrefutable proof that you are wrong. The SPD article DIRECTLY cites the NEC. Are you somehow inferring that you are right and they are all wrong and that I have disrespected you? I have been kind to you all along Steve. I have pointed out the many errors you have made, but I have been kind.
Worse, as Stu pointed out the very article YOU linked to that was published by
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Young Frankenstein
New member
Cuttlers Hammer electrical engineers remarks, this is switch gear engineer "Above or equal to the fault current rating of the power company", it is the reverse of my saying. I will ask the switch gear engineer from GE tomorrow, and maybe the chief electrical inspector, my gut feeling is telling me I could be wrong.
stugray
Premium Member
Actually, in YF's defense....
While thinking through what he was saying ( as applied to transient surge protection NOT breakers or appliances ),
I thought of one case where it would be BAD for the surge supressor to be able to conduct MORE surge than the MAIN BREAKER is capable of interrupting ( This is the AIC rating).
IF you installed a HUGE surge supressor on the House side of the main breaker, AND it absorbed 70kA of current ( microseconds to milliseconds depnding on the "surge"), when the Main breaker is only rated at say...30kA, then it is possible to weld the Main Breaker's Contacts closed.
This would neutralize the Main breakers Interrupt Capacity for future faults, and the homeowner would never know it.
This is the ONLY case where I can see not wanting the downstream side components to NOT have greater AIC than the service feed.
However, I applaud YF's remark above. Thank you.
Stu
While thinking through what he was saying ( as applied to transient surge protection NOT breakers or appliances ),
I thought of one case where it would be BAD for the surge supressor to be able to conduct MORE surge than the MAIN BREAKER is capable of interrupting ( This is the AIC rating).
IF you installed a HUGE surge supressor on the House side of the main breaker, AND it absorbed 70kA of current ( microseconds to milliseconds depnding on the "surge"), when the Main breaker is only rated at say...30kA, then it is possible to weld the Main Breaker's Contacts closed.
This would neutralize the Main breakers Interrupt Capacity for future faults, and the homeowner would never know it.
This is the ONLY case where I can see not wanting the downstream side components to NOT have greater AIC than the service feed.
However, I applaud YF's remark above. Thank you.
Stu
