On 2/18/2014 1:57 PM, Robert Green wrote:
"bud--" wrote in message news:53025e07$0$47887$c3e8da3

stuff snipped

As gfretwell wrote, AFCI receptacles are now available. In addition to
installing them as in his post, you could put AFCI receptacles next to
the panel and use the wire-through feature to protect existing circuits.

I wired in three new 20A circuits to service two space heaters and a
convection combo oven. Since I knew where the first outlets were on the
branch circuits I simply replaced those outlets with Leviton AFTR2-W
SmartlockPro Outlet Branch Circuit Arc-Fault Circuit Interrupter
Receptacle, 20-Amp units ($25 each at Amazon) and connected the downstream
outlets through the load connections.

New in the 2011 NEC - if you extend an existing circuit in an area where
AFCI protection is required the extension (including wiring) must be
AFCI protected. Wiring through an AFCI receptacle (as you did) is one
way to provide that protection. Almost every receptacle in a dwelling
must now be AFCI or GFCI protected (when originally wired or replaced).
In the 2014 NEC some must be both.

Also new in 2011
- replacement receptacles in areas where AFCI protection is now required
have to be AFCI protected (several methods)
- replacement receptacles in areas that now require tamper-resistant
receptacles must be tamper-resistant (that is most of the general
purpose receptacles in a dwelling)(keeps kids from putting paper-clips
in the receptacle)
- replacement receptacles in areas that now require weather-resistant
receptacles must be weather-resistant (damp locations, like outdoors)

And replacement receptacles where GFCI protection is now required must
be GFCI protected

AFCI or GFCI receptacles may have to be tamper-resistant or
weather-resistant.


The only real downside of doing that is that when an AFCI outlet trips, you
have to roam around the house looking for it. I've made an addendum to the
ever-growing list of notations inside the panel door of where they are
(along with GFCI's wired the same way) but it still complicates things.

There are circuits I'd like to protect where I don't necessarily know where
the first outlet in the chain happens to be (is there a way to determine
that?) so they would have to be protected by AFCI breakers instead of AFCI
outlets.

Or install AFCI receptacles at the panel as in my last post.


The circuit breaker AFCI's are almost twice as expensive and require a
neutral pigtail connection in the circuit breaker panel. Since my neutral
bar is already at capacity, the outlets seemed to make more sense cost-wise
and installation-wise.

I have a question for you. Is it "code" to use two neutral buss bars in a
circuit breaker panel? The one I just bought is rated for putting two 12
gauge wires under one screw but I don't like to do that if I can avoid it.
I could remove the old one and replace it with the one rated for two wires
per terminal and double up all the neutrals but I would rather install a
second one on the opposite side of the panel and still connect one wire per
terminal. Just not sure that two separate neutral buss bars is permissible.

You can double-up wires only when the manufacturer says it is allowed.
Look at the label for the panel. Neutrals are never allowed to be
doubled-up - it is a code violation (408.41).

It is relatively easy to add ground bars. The label for the panel should
say what accessory bars can be used. If you have ground wires on the
existing neutral bar they can be moved to the ground bar (and maybe
doubled-up). Neutrals can not be landed on a ground bar (the enclosure
can not be used as the neutral-path connection from ground bar to
neutral bar in a service panel).

I don't know if accessory neutral bars are available. They are not as
easy to install. Other than in a service panel, they have to be
insulated from the enclosure, and you have to figure out the size of the
conductor to connect it to the existing neutral bar.


I have to admit since reading about what you wrote about the UL tests I am
not sure arc fault protection devices are worth all the effort. I've had
two meltdowns already from plugs that were either not fully plugged in or
had come loose and one because an six-outlet adapter's crimped internal buss
bar worked itself loose. It would be nice to know if the AFCI could have
detected any of those events. I am beginning to think they might not have.

Was it a high resistance or arc? Some loose connections are an arc. In
the research done for Cutler-Hammer about 1/2 of the high resistance
connections resulted in a ground fault trip when leakage to ground
resulted from the heat. The 30 mA ground fault trip in an AFCI is there
for that reason. And a "glowing connection" may turn into an arc.

The NEC keeps increasing the locations where AFCI protection is
required. Would be nice if there was data that showed they have a major
effect. But they will likely be most useful as the wiring ages.