circuit breaker violation

[Johnny Elliott]

I know the electrical code disallows "double gang" circuit breakers (two branch circuits on a single pole 20 amp breaker. What is the safety issue with this set up? Will the breaker fail to trip in time to prevent an over current in the branch circuit(s)? Can you quantify the safety issue that occurs when two No. 12 branch circuit wires are double poled on a single pole 20 amp breaker. Does the violation cause the wiring to overheat and degrade the insulation? What is the potential issues with this violation.

 

[charlie b]

I think the problem is with the point at which the two #12 wires connect to the breaker. If the breaker's manufacturer has not designed the terminal to accept two wires, and if they have not had the breaker listed for that application, then you cannot be confident in getting a good electrical connection on either wire. That would mean the connection point would have a higher than normal resistance, which in turn could lead to overheating.

I don't think there is any issue with the breaker tripping. If you have 15 amps running on each of the two circuits, the 20 amp breaker will see a total of 30 amps, and will eventually trip. Having the second wire connected to the breaker will not inhibit the breaker's ability to trip, nor will it alter the breaker's time-current characteristic curves.

 

[bphgravity]

It doens't have anything to do with the loading of a circuit. It has to do with the rating of the termination. If the lug / termination type isn't listed as suitable for more than one conductor, you will not be able to properly torque the connection and ensure proper operation.

If you want to serve two circuits from one breaker, just simply splice the conductors and "pig-tail" one conductor to the breaker. Some breaker manufacturer's have their terminations listed for more than conductor.

 

[bthielen]

This may seem like a silly questions but what is the difference to the terminal between two solid core conductors or one stranded conductor, which has many more than two wires?

If the terminal can accept one stranded conductor, why not two?

Bob

 

[roger]

Re: circuit breaker violation

I know the electrical code disallows "double gang" circuit breakers (two branch circuits on a single pole 20 amp breaker. What is the safety issue with this set up? Will the breaker fail to trip in time to prevent an over current in the branch circuit(s)? Can you quantify the safety issue that occurs when two No. 12 branch circuit wires are double poled on a single pole 20 amp breaker. Does the violation cause the wiring to overheat and degrade the insulation? What is the potential issues with this violation.

Actually if the breaker is listed for two conductors this is legal and infact is a common practice.

SQ D and C-H both list many of their 10 to 30 amp breakers for use with two conductors.


Roger

 

[Johnny Elliott]

circuit breaker violation

How severe of a safety issue has the trip failures for Federal Pacific Electric (FPE) Stab-Lok circuit breakers been? I get some info off the net but have not been able to quantify the magnitude of the issue. Would the "double gang" violation exacerbate these failures?

 

[charlie b]

Before I let this go any further, I have to ask for the purpose of your questions.

One of the Forum rules is a prohibition against using information posted by any Forum member in a legal dispute. No member of this Forum is to be considered an "expert witness," and no information posted by any member is to be considered "evidence."

If you are investigating an actual event, and you are trying to understand possible causes, then I think we can be of assistance. If you are seeking information to support a case against, or in favor of, one party in a lawsuit, an insurance investigation, a criminal investigation, or any other legal proceeding, then I would have to ask you to find another source.

To all other Forum members, let me ask you not to post any new comments until this issue is resolved.

 

[Johnny Elliott]

My question is not to be used in a legal forum. My question is to try and understand why some code inspectors allow double gang installation and some do not. Obviously, there is a potential safety mechanism inferred by the exclusion. Just trying to understand the physics of the issue. If you are uncomfortable with that primise, don't respond.

 

[charlie b]

That is fine. I apologize for the delay and the inconvenience, but I hope you understood my concern. We have had lawyers start asking questions that were worded in such a way as made it clear they were trying to blame someone else for an injury. The Forum Owner, Mike Holt, does not want us to get in the middle of such disputes.

To all other Forum members: let the discussion continue.

 

[Johnny Elliott]

Mr. Beck, P. E. I suppose you have assumed the role of "gate keeper" for the forum discussions. I guess that is an issue for the forum to decide, but let me assure you that I don't believe anyone is naive enough to take anything from a technical forum "chat room" to the courtroom as "expert" or "evidence". Take a breathe.

 

[charlie b]

My question is to try and understand why some code inspectors allow double gang installation and some do not.

There are two issues involved with that question. The technical issue is whether or not the practice is "legal," meaning, "code compliant." The answer, as several of us have said, is "yes," if (and only if) the manufacturer tells you that you can do this with their breaker.

The other issue relates to whether a code inspector will allow the practice. I see three facets of this issue. First, some inspectors will enforce what they believe to be "the right way," whether or not that is the same as the code requirements. Secondly, some inspectors will be constrained not only by NEC requirements, but also by local laws and rules. So even if the NEC allows an installation, local codes might prohibit that installation. Finally, some inspectors might not understand the relevant code requirements, and might be incorrect in their enforcement decisions. The good ones will change their rulings, if someone does them the courtesy of inviting their attention to the proper code sections and discussing the meaning of those code sections.

 

[charlie b]

Mr. Beck, P. E. I suppose you have assumed the role of "gate keeper" for the forum discussions.

Actually, I have been appointed "Chief Moderator" by Mike Holt. We just changed to a new format for this code forum. The earlier version said so, right under my name. I had not noticed that the new format did not state my role. Thank you for pointing that out. I will see what I need to do to correct this.

. . . but let me assure you that I don't believe anyone is naive enough to take anything from a technical forum "chat room" to the courtroom as "expert" or "evidence".

Let me assure you that several have tried. I even recall getting a Private Message from one lawyer, when I told him that this Forum cannot assist him with his lawsuit. I was told that I was a heartless and cruel person not to want to assist the poor accident victim. At this point, I was given a detailed description of the person's injuries, and was told I should be ashamed.

 

[roger]

Johnny,

Take a breathe.

for someone wanting help you sure have an awkward way of going about getting it.

Charlie B does an excellent job here, is well respected and is very fair, if you feel you are being talked down to so be it.

Roger

 

[templdl]

Johnny Elliott,
I may have missed something but what do you mean by "double gang" breakers? Are you referring to 2 poles of breakers in one space? Is it a duplex breaker.
Also, if you are referring to (2) wires in a single termination or under one screw, as the others related only the type and number of wires that are listed by the manufacturer can be terminated.
Should you have a 20a breaker where (2)#12 are allowed and you terminate 2 #12s, then the breaker will respond the combined current of both conductors. It's kind of a waste because if one conductor is already carrying 16a continuous, what capacity is left for the second conductor?
If there is an extra space a second breaker should be installed and that second conductor mover there.
Dave

 

[realolman]

Re: circuit breaker violation

Actually if the breaker is listed for two conductors this is legal and infact is a common practice.


Roger

How, specifically do you find that out?

I have the "Bogus OP20" breaker in my hand. How do I find out if it's rated to put two conductors in the lug?

 

[roger]

Realoman, generaly speaking, if it is a "pressure plate" type of lug it is suitable for two conductors but without the "listed for" to back it up, it wouldn't matter.

The information is on the breaker in the way of a sticker or engraving but that doesn't mean it is still there or even legible.

The best way is to get the information from the manufacturer.

Go to the SQ D link below and scroll down to the "Wire Size Chart" at the bottom of the page and look at the 1 and 2 pole breaker info for an example.

http://ecatalog.squared.com/catalog/173/html/sections/06/17306010.html

Roger

 

[haskindm]

110.14(A) states "Terminals for more than one conductor and terminals used to connect aluminum shall be so identified." If the terminal is not labeled that it is suitable for more than one conductor, then only one conductor may be installed. If the terminal is not labeled that it is suitable for aluminum conductors, then copper condutors must be used. So a terminal that has no markings on it must be used with a single, copper conductor.

 

[JohnE]

Mr. Beck, P. E. I suppose you have assumed the role of "gate keeper" for the forum discussions. I guess that is an issue for the forum to decide, but let me assure you that I don't believe anyone is naive enough to take anything from a technical forum "chat room" to the courtroom as "expert" or "evidence". Take a breathe.

Johnny,

Charlie was the first to answer your question, locked it when he saw a red flag until questionable motive was answered, and then apologized after unlocking it. You then insult him with the above statement.

Charlie does an excellent job as a moderator.

I'd recommend an apology.

 

[ramsy]

Wh-a-a-a-a-a, Charlie handled himself fine. Besides, bashing the moterator is not one of the forbidden topics.

 

[charlie b]

Besides, bashing the moterator is not one of the forbidden topics.

True. But targeting of that kind of special treatment should not be limited to Moderators. We expect "Equal Opportunity Bashing" here! :wink: :lol: