An Effective Ground-Fault Current Path?

[cbaman]

I have re-opened for discussion.

Thank you very much Dereck. I appreciate the opportunity to have a discussion with the forum members on these issues.
Paul

 

[cbaman]

I believe this is something better aimed toward the UL.

George,
The NEC frequently stipulates specific product performance requirements. Chapters 3 and 4 are full of such product requirements. How is this proposal any different from so many other requirements that spell out performance requirements for a product?

Paul

 

[cbaman]

1 second is 60 cycles, correct? What's wrong with one second? Or four? It's for protection of equipment, not personnel...?

George (and Ryan from another post),
1 cycle is specified because 1 cycle is the present magnetic clearing time specification for all 5 major product lines of standard circuit breakers. (Square D, Cutler-Hammer (CH & BR), Siemens and GE). This is the time that the breaker takes to clear the line, once its magnetic response has been engaged. What varies from brand to brand is the amount of fault current required to trigger the magnetic response. Until that threshold current is reached, the breaker remains in thermal mode.

By specifying 1-cycle, the manufacturers do not have to make any adjustments to the present product specifications in order to comply with this proposal. So that's the reason for 1 cycle.

Paul

 

[iwire]

I have heard many concerns expressed here and on other forums about the length of branch circuits (and the resulting voltage drop at outlets) in some of the large homes being wired today. The underlying problem that I hear with these concerns is that we lack sufficient information with which to make an sound decision. These two proposals will fully address this problem.

Paul

Address what problem?

As you pointed out in your post we lack sufficient information.

IMO the first step would be to verify the issues than make a code change.

You appear to want to do the reverse...make a code change and then see if the results justify the costs of the change.

IMO the 40,000 electrical fires a year figure is not a reliable number and does not reflect the amount of fires that would be prevented by a faster breaker response.

Obviously any reduction in fires is a good thing but all code issues have a cost vs benefit that should be considered.

I do agree with Don that this proposal is a likely to do more good than the AFCIs that still do not do what was promised.

All that aside I still wonder if the real motive here is sales just like the AFCI section.

 

[cbaman]

You lost me Don, it sounds to me like the proposal would add a performance requirement.

Bob,
The first proposal, 10-55, before CMP-10 now, standardizes the magnetic trip performance requirements in all circuit breakers installed in dwelling units.

The second proposal for article 210, not yet proposed, would indeed add a performance requirement for branch circuit outlets that the voltage drop at the furthest outlet of a branch circuit could not exceed 9%, for safety reasons, to ensure compliance with 250.4(A)(5). Compliance could be easily checked in the field by an inspector with a voltage drop measurement device. Several manufacturers presently make voltage drop measurement devices.

Paul

 

[cbaman]

Address what problem?

Compliance with 250.4(A)(5).

 

[iwire]

Compliance with 250.4(A)(5).

Please do not run me around in circles.

Can you show that a faster breaker response is going to reduce electrical fires?

Could you later show that reducing VD will reduce electrical fires?

That is what it should take to change or add to the NEC.

Not assumptions based on questionable data.

JMO, Bob

 

[don_resqcapt19]

Bob,

All that aside I still wonder if the real motive here is sales just like the AFCI section.

No change in sales here...just a change in the performace requirements for breakers that are already required to be installed by the NEC.
Don

 

[iwire]

Bob,

No change in sales here...just a change in the performance requirements for breakers that are already required to be installed by the NEC.
Don

Yes I agree as far as the first proposal.

As far as the second proposal there is more sales to be had.

 

[cbaman]

You appear to want to do the reverse...make a code change and then see if the results justify the costs of the change.

I want to specify certain product performance requirements in the NEC so that the NEC user understands what performance is expected and to achieve compliance with 250.4(A)(5).

Obviously any reduction in fires is a good thing but all code issues have a cost vs benefit that should be considered.

Cost of the change is neglible. The proposed changes are current practice for 3 of 4 manufacturers. One would have to make an adjustment to its present trip settings.

All that aside I still wonder if the real motive here is sales just like the AFCI section

Bob, I'm 58 years old and have been a practicing service electrician for 30 years. 20 years ago I began pursuing the problem of why some circuit breakers do not seem to respond quickly to shorts or ground-faults. Finally, after 10 years of development in my spare time, I finally introduced the first tester capable of safely conducting an in-situ field test of the short-circuit response of an installed circuit breaker. That is the technology that I have developed and patented. 3 years after its introduction, I still feed my family with my electrical service work that I continue to do full-time, as I also continue to refine the technology that I have worked so long and diligently to develop.

Why? Because I firmly believe that it is about time that electicians like ourselves should be able to tell our customers how well the circuit breakers protecting their homes are doing their job. I am often called upon to evaluate the safety of the electrical system in older homes. And frankly Bob, I find it embarrassing that as a professional electician, I have no way to evaluate the circuit breakers in a home. To do this, I needed a tool that did not exist, so I invented it.

I don't know what else to say about this subject, except that I share the same skepticism as you and many others do about the manufacturing side of our industry. My recent experience has brought me in direct contact with this side of the industry, and I still view myself as an electrician trying to solve problems I experience in the field, rather than someone trying to cash in on an opportunity.

Do you see any requirement to test circuit breakers in either of these proposals? Yet at the same time, do I hope the technology I have spent my career developing will one day receive recognition and success?
What do you think?

Paul

 

[cbaman]

Please do not run me around in circles.

In 2005 the NEC accepted 2 new articles, 250.4(A)(5) and a new definition for an Effective Ground-Fault Current Path in 250.2. I have produced field test results that document that this requirement is not being met in almost 60% of the outlets in a sample of more than 1000 tests. I'm not running you in circles. There is a compliance issue here that involves circuit breaker performance.

Can you show that a faster breaker response is going to reduce electrical fires?

Clearing a short-circuit or a ground-fault as rapidly as possible is just common sense to me. Why would anyone want such a condition to remain energized any longer than necessary?

Could you later show that reducing VD will reduce electrical fires?

You seem to think that the only thing I'm trying to address is fires. Not so. I'm trying to point out that if you want circuit breakers to clear faults quickly, for whatever reasons, then I have outlined certain steps that need to be taken to achieve that. If you're happy with circuit breakers staying in thermal mode in response to short-circuits or ground-faults and taking up to several seconds to clear fault currents of 100-600 amps (fault current that just might be sparking), then you would see no value in this proposal.

That is what it should take to change or add to the NEC. Not assumptions based on questionable data.

No one has done the research that provides the answers we seek. Until the research proves otherwise, I believe we should take the safest approach to the problem of what starts fires.
Paul

 

[iwire]

Do you see any requirement to test circuit breakers in either of these proposals?

I see a requirement to test for circuit performance in you second proposal.

If I am not mistaken your device is capable of that.

I won't bring this up again, no matter what your motives IMO there is an appearance of a conflict of interest.

As far as the first proposal I don't see any issue other than it is IMO outside the stated boundaries of the NEC.

Yes there are many sections in the NEC that are more product standards not codes but IMO they should be removed and new ones should not be added.

Admittedly that view seems to be in the minority and goes against the current direction the NEC is moving.

 

[don_resqcapt19]

Bob,

As far as the second proposal there is more sales to be had.

There are a number of testers that cost 1/4 or less than breaker tester that can test for voltage drop. If that would be a code rule, I don't see it driving the sales of the breaker tester.

Don

 

[cbaman]

As far as the first proposal I don't see any issue other than it is IMO outside the stated boundaries of the NEC.

Bob, I can't find where it says that this proposal is outside the stated boundaries of the NEC. I see in 90.1(B) Adequacy. the statement, "This Code contains provisions that are considered necessary for safety." Proposal 10-55 is to standardize the short-circuit response of circuit breakers with the objective of improving protection from fault current, clearly about safety. I don't see any prohibition anywhere in Article 90 that would preclude this proposal. If you are referring to some other specific language that places this outside the jurisdiction of the Code, please point that language out.

This comment is similar to George's post #4 saying this proposal belongs with UL. I think the above statement in 90.1 allows the NEC to make any requirements it sees fit that are related to the electrical safety of installations. Since all installations include products that are installed, the established protocol seems to me is for the NEC to stipulate specific performance requirements in products where it deems them necessary based on safety and then for the standards process (UL and others) to implement those requirements in the products. That is why Chapters 3 and 4 are full of product requirements. Maybe you would be more comfortable if this were in Chapter 4- Equipment for General Use, but there is no article in Chapter 4 covering circuit breakers. All requirements for circuit breakers are detailed in Section VII of Article 240, where this has been proposed.
Paul

 

[iwire]

Bob,

There are a number of testers that cost 1/4 or less than breaker tester that can test for voltage drop. If that would be a code rule, I don't see it driving the sales of the breaker tester.

Don

Well we will have to disagree.

It is my nature to be skeptical of anyone that has something for sale.

I could be entirely wrong.

 

[iwire]

Bob, I can't find where it says that this proposal is outside the stated boundaries of the NEC. I see in 90.1(B) Adequacy.

I see in 90.1(C) Intention. This Code is not intended as a design specification or an instruction manual for untrained persons.

If specifying how a breaker manufacturer produces their products is not a design specification I do not know what is.

I see in 90.2 Scope.
(A) Covered. This Code covers the installation of....

The construction and design of a breaker is not the installation of a breaker.

That said I agree there are many similar requirements in the NEC, that does not mean another should be added or that the existing ones should not be removed.

Heck now they mandate what kind of Xmas lights must be used and how vending machines will be constructed. Before long we will need a two volume NEC.

I do not see why these issue would not be better handled in product standards rather than a premises wiring standard.

 

[Bob NH]

BETTER is the Enemy of GOOD ENOUGH

BETTER is the Enemy of GOOD ENOUGH

It is always possible to find ways to spend money to improve life safety. There are economic analyses of safety decisions in construction of pipelines, electric utility systems, highway designs, airplanes, automobiles, medical care, and numerous other products. The choice comes down to whether the money should be spent on those things that could marginally improve safety, or on other things that people may choose.

People who make regulatory decisions related to their own economic self interest are spending "Other people's money". Those cases should be challenged and rigorously tested for economic value.

The suggested "Improvement" in the code is not supported by any evidence that clearing faults in 1/2 cycle is going to improve safety more than spending the same amount of money on prenatal health care or wider roads or anti-smoking campaigns.

The assertion that "Faster clearing of faults is better" is the kind of argument that compels other people to have to spend their money without any demonstrated economic benefit. The NEC should stick to solving real problems.

 

[cbaman]

It is always possible to find ways to spend money to improve life safety.

This proposal would not cost anyone anything. The proposed measures are current practice for 3 of 5 major lines. Two would have to adjust a setting at the factory.

The NEC should stick to solving real problems.

Read 250.4(A)(5). CMP-5 thinks that not clearing ground-faults quickly is a real problem.

 

[cbaman]

I see in 90.1(C) Intention. This Code is not intended as a design specification or an instruction manual for untrained persons.
If specifying how a breaker manufacturer produces their products is not a design specification I do not know what is.

This proposal does not specify how a manufacturer should produce a product; it merely specifies what performance is required, not how it should be accomplished. That's product design, and that's up to them. You're confusing performance specifications with product design. They are not the same.

I see in 90.2 Scope.(A) Covered. This Code covers the installation of....The construction and design of a breaker is not the installation of a breaker.

This point is difficult to challenge. I agree, this statement seems to limit the scope of the NEC solely to the installation of products, yet chapters 3 and 4 are all about specifying what the NEC wants to see in product requirements. I will ask someone at the NFPA for a comment.