Electrical Industry Canada: Arc Flash, Shock Hazard, & Fire Safety - 19

Explain why a GCFI circuit also needs to be on an Arc Fault
Breaker?
Arc-fault protection: a means of recognizing characteristics unique
to both series and parallel arc-faults and de-energizing the circuit
when an arc-fault is detected.
Class A GFCI: a ground fault circuit interrupter that will interrupt the
circuit to the load, within a predetermined time, when the ground
fault current is 6 mA or more but not when the ground fault current is
4 mA or less.
" With arc-fault we have series and parallel arc-faults. What that
means is if I have a break in the wire, the arc-fault breaker can detect
that break in the wire and that arcing. That arcing can create a fire,
however, may not draw enough current to operate the over current
device. So, the AFCI device can detect that and prevent the fire. "
With parallel arcing, Brown said, it's the same, " the microprocessor
and the arc-fault breaker is supposed to be able to detect that fault
and interrupt. "
" Ground fault protection is really about the protection of people. "
A ground fault receptacle or breaker, " they basically have two current
transformers and they compare what's going out to what's coming
back, if a person was to touch an energized portion, because they're
standing on the ground they're also grounded, they could potentially
be electrocuted whether it's by the pool, at the bath tub, or with these
new receptacles that we're talking about at outdoor facilities - there's
a potential for electrocution. This current transformer looks at the fault
path and says, 'hey, the current's going somewhere else, it's not going
back on the wire,' and if there's a small difference there it will trip and
protect the person. "
" So, really the reason why you need both requirements, for example
on an outdoor receptacle. The outdoor receptacles need ground fault
to protect the person, and it needs AFCI to protect the wiring
between the receptacle and the panel from electrical fire. "
Arc Fault Breaker placement reasoning?
Rule 26-656
Unless there is enhanced wiring methods used, the AFCI device must
be at the start of the circuit as downstream devices are not able to
interrupt upstream parallel faults.
ELECTRICAL INDUS TRY CANADA
" What I got from this questions was, why does the arc fault have to be
at the panel or at the first devices? The reason for this is by placing the
arc fault at the first device or at the panel (the first device would require
enhanced wiring methods), it is able to interrupt any fault downstream
from parallel or series faults. If my arc fault devices was at the last
receptacle and I had rodent damage (upstream), the device would not
be able to interrupt the fault. "
Can ESA push manufacturers to stop making receptacles that
allow push in connections as it appears to create unwanted
tripping for AFCI breakers?
Receptacles are approved and tested for use with copper conductors
with push-in terminations. Incidents of failure that fail dangerously
should be reported to www.health.canada.ca for investigation.
" Changes to products are usually based on failures, fires, or proposals
- but at this time, we haven't been seeing them. "
Brown added that in order to impact change, you need to report what
you see to Health Canada, " and that's not just limited to receptacles,
any electrical products. If it's a consumer product you can report it to
Health Canada.
If it's a non-consumer product, for an industrial facility, for example,
Brown said it can be reported to ESA. Their product safety group will
go through the product incident process.
Why do existing basement units need arc fault breakers? Are
arc fault breakers only for new construction?
Rule 26-656 requires AFCI for new branch circuits in new or existing
for dwelling units.
" When I'm running a new circuit I follow the new code, " Brown said,
" When you're running something new, the current code applies. "
" If I'm running a whole new branch circuit from the panel, I would have
to have that AFCI, either at the breaker in the panel or at the first
device with enhanced protection between the first device and the
panel. "
When adding an additional receptacle to an existing circuit, an AFCI
receptacle (or dead front) is required to be installed at the first receptacle
on the extension of the circuit.
The existing devices don't require AFCI protection, although its
recommended for the added safety benefit.
VOLUME 1, ISSUE 6
19
https://www.canada.ca/en/services/health/report-health-safety-concern.html
Electrical Industry Canada: Arc Flash, Shock Hazard, & Fire Safety

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