Arc Fault Main Breaker, someday??

[sparky_pdx]

I'm just curious, if panel designers could ever come up with such a thing. It would save loads of $$$, buying those #%! individual AFCI breakers, as well as freeing up panel space & allowing 3 wire homer runs, saving copper & $$$.

I read somewhere in the code, that a AFCI receptacle might be available someday, that would be way cool...Anyone know about such a thing??

Thanks in advance,
Sparky in Portland, OR

 

[sparky_magoo]

I think the manufacture's of AFCI breakers would hate your idea.

 

[iwire]

I doubt any will want a 'main' AFCI any more then a 'main' GFCI.

You really don't want a minor problem on a branch circuit dumping the entire panel.

 

[iwire]

I read somewhere in the code, that a AFCI receptacle might be available someday, that would be way cool...Anyone know about such a thing??Thanks in advance,

An AFCI receptacle would have very limited use.

The NEC requires that the entire branch circuit be AFCI protected, you could not protect the entire branch circuit with a AFCI receptacle unless that AFCI receptacle was located at the panel. This could be handy when adding a circuit to an old panel that AFCIs are not available for.

Keep in mind this is different then the GFCI requirements which only require GFCI protection of the receptacle, not the entire branch circuit.

 

[don_resqcapt19]

Bob,

The NEC requires that the entire branch circuit be AFCI protected, you could not protect the entire branch circuit with a AFCI receptacle unless that AFCI receptacle was located at the panel.

Under the 2008 rules, if you use a metallic sheathed cable or metallic conduit, you do not have to provide AFCI protection for the part of the circuit between the panel and the first outlet. This exception was limited to six feet in the 2005 code. This opens the way for the use of AFCI receptacles. I think that the hope is that there will be a price difference between AFCI breakers and receptacles like there is between GFCI breakers and receptacles. I don't think this will happen unless a lot more areas adopt a code like Chicago's.
Don

 

[480sparky]

I think the manufacture's of AFCI breakers would hate your idea.

I think the users of AFCI main breakers would be howling as soon as a problem developed.

 

[Pierre C Belarge]

Bob,

Under the 2008 rules, if you use a metallic sheathed cable or metallic conduit, you do not have to provide AFCI protection for the part of the circuit between the panel and the first outlet. This exception was limited to six feet in the 2005 code. This opens the way for the use of AFCI receptacles. I think that the hope is that there will be a price difference between AFCI breakers and receptacles like there is between GFCI breakers and receptacles. I don't think this will happen unless a lot more areas adopt a code like Chicago's.
Don

I believe this permission was installed in the NEC to help relieve people who do not have panels that will accept AFCI type CBs.

I am not too sure how fast the manufacturers are working (spending their money) on developing receptacle type AFCIs. :wink:

 

[ELA]

I doubt any will want a 'main' AFCI any more then a 'main' GFCI.

You really don't want a minor problem on a branch circuit dumping the entire panel.

How true.

We sold equipment in Korea and the customer required us to use a 200Amp- 3 phase "delta connected" GFI main (30 ma trip). They required all suppliers to imploy a GFI main. These breakers often "nuisance-false" tripped due to noise in the industrial environment.

This resulted in a lot of costly down time. They then paid to have various GFI breakers to be EMC tested at a 10volts/meter immunity level (industrial strength). Only breakers that passed that requirement were allowed going forward.

 

[beanland]

Follow the money

Follow the money

Though "safety" is supposed to be the driving force behind the NEC, remember that manufacturers are the major force behind changes. Profit always plays a role. The reason we have GFCI receptacle requirements is because someone made a GFCI receptacle and convinced the "powers that be" that it was needed. If they have made GFCI breakers first, we would have mandated GFCI circuits and not GFCI receptacles. AFCI circuit breaker manufacturers have done the same thing, they made a product then got it mandated. If the manufacturers came up with AFCI receptacles and not breakers, we would be installing them.

I want to invent the next great product and get it mandated!

 

[brantmacga]

Though "safety" is supposed to be the driving force behind the NEC, remember that manufacturers are the major force behind changes. Profit always plays a role. The reason we have GFCI receptacle requirements is because someone made a GFCI receptacle and convinced the "powers that be" that it was needed. If they have made GFCI breakers first, we would have mandated GFCI circuits and not GFCI receptacles. AFCI circuit breaker manufacturers have done the same thing, they made a product then got it mandated. If the manufacturers came up with AFCI receptacles and not breakers, we would be installing them.

I want to invent the next great product and get it mandated!

mmhmm. equipment manufacturer's were a little bit smarter this go round. $10 recep vs. $30 cb??!!

 

[plate]

An AFCI receptacle would have very limited use.

Agreed. But some day we may have a main breaker that incorporates some portions of AFCI detection to look for faults occuring within the panel (loose connection on a standard breaker), as is the case with some protective relays. I don't know if this will happen in my lifetime.

But then again, there will be less and less standard breakers in panels as NEC2008 comes into use.

 

[Jraef]

The equivalent of AFCI main breakers exists all over the rest of the world (called RCD breakers). There are specific rules in the US that prohibit their use at this time. It is too complex to go in to here (and likely more political than technical anyway), but suffice to say that breaker manufacturers have them available right now, they just can't be used domestically. They are used a lot in semiconductor manufacturing tools that go to Asian countries where they are required, but the 30ma versions are constantly tripping on nuisances already, using them as mains would be a pain in the rear. I have seen where most of them are disabled after installation, so what's the point?

 

[don_resqcapt19]

Pierre,

I believe this permission was installed in the NEC to help relieve people who do not have panels that will accept AFCI type CBs.

I think that was the intent when the exception was put into the 2005 code. That exception was limited to 6'. Under the 2008 code, the 6' limit was removed and the exception was reworded to permit the AFCI device at the first outlet.
Don

 

[don_resqcapt19]

Jeff,

The equivalent of AFCI main breakers exists all over the rest of the world (called RCD breakers).

Aren't RCDs more the equivalent of GFPs and not AFCIs? Also what rules would prohibit their use in the US now?
Don

 

[Jraef]

The "rules" (poor choice of words on my part) are precisely the issue of the differences between a GFP and an AFCI, and an RCD being something that is neither or both. It's apparently a little too blurry for UL, plus the RCDs are adjustable, something UL has a hard time with because the protection level becomes up to the installer and can be changed later. Like I said, it comes down to politics and philosophy more than technology. Here in the US we would rather legislate and enforce to try to prevent people from making mistakes, elsewhere they expect everyone who is allowed to work on something to know and do exactly what is right and if you get killed, you don't matter any longer anyway, or if someone else gets killed, you don't work in that field for the rest of your life (or are encouraged to do yourself in).

 

[plate]

As Jreaf has mentioned, a RCD is neither a AFCI of GFI breaker. The purpose of the AFCI is fault detection and in the RCD it is not.

 

[don_resqcapt19]

I though that a RDC was a residual current device and that if works in the same way as a GFCI, but with a higher trip point. Is that not correct?
Don

 

[plate]

Don, I stand (sit) corrected, thanks for the link.