Hi Jim,
Your e-mail got me to thinking about a few of the ideas
presented. Here are some opinions:
1. If a product that uses electricity does not fall into the scope
of any published safety standard, then the NRTL could "make
something up." But some people can interpret "making something
up" to imply that the resulting requirements are bogus and unnecessary
because they are not drawn from a formal standard that has gone
through a thorough industry review process, official publication and
formal adoption.
But all products that use electricity have the potential to pose some
kind of a safety hazard if certain parameters are not limited
by some reliable means. And if such products are not designed in
consideration of potential hazards by people with experience in
product safety, then hazards can be unintentionally designed
into them.
In fact, there usually is a great deal of sound engineering that
goes into developing new requirements to address an electrical
product that does not fall within the scope of a published standard.
Much can be drawn from published standards which address similar
constructions/uses to that of the new device being evaluated. This
can
be augmented by the experience of engineers that are familiar with
safety principles and standards development.
So I think it is fair game to develop requirements "on the fly" to
evaluate the safety of new products which have never been "approved"
by an NRTL previously. But the NRTL should not go overboard,
nit-pick,
delay, etc in evaluating such products. Overevaluation would probably
be more likely with inexperienced safety engineers who should not
be working on such products in the first place. And I know that this
does
happen.
2. Your hypothetical clock can contain hazards which the electrical
inspector
does not and can not evaluate. Let say the clock has no currently
limiting
aside from the branch circuit protection. And it develops a limited
short
circuit within that causes an internal component to overheat without
taking
out the branch circuit overcurrent protection. And it has
a component that overheats and ignites some flammable material within.
And it is enclosed in a plastic having an enclosure of flammability
rating
94HB or worse. The enclosure ignites when there is no one in the room
and does not self extinguish. Flammable material on a table below
the clock catches fire from the dripping, flaming enclosure particles,
and so forth, and so on. The electrical inspector determined that the
clock was installed per the NEC, but we still had a problem.
One area that I think we would agree is that the NRTLs do not corner the
market on qualified safety engineers by any means. So if a company
had "certified safety engineer(s)" on staff (with P.E. licenses?), AND the
engineer(s) were responsible for approving the utilization equipment,
AND, the engineer(s) were subject to periodic review or relicensing,
THEN, a self-declaration process could used in lieu of formal "approvals"
by an NRTL.
While I am fully in favor of EMC self certification, I think that an NRTL is
a "value-add" for product safety and that something more stringent
is needed then an anything goes self-certification method for
product safety. I think that, in most cases, safety failures have much more
of a potential to be life-threatening, hence the more stringent
considerations.
Regards,
[email protected]
----------
From: Jim Stafford
To: EMC-PSTC
Subject: OSHA 29 CFR 1910
List-Post: [email protected]
Date: Wednesday, February 05, 1997 2:26AM
Thanks for the input on the interpretations from OSHA.
I went out to the WEB site and took a look at some of the letters concerning
"approved" equipment.
The first thing that suprised me was the broad brush strokes that OSHA takes
with this standard.
I am still wondering why the NEC code panel did not clarify the definition
of
utilization equipment by defining it as
"all equipment which utilizes electric energy". This should pretty much
cover
it.
In the first interpretation it is written
"All electrical equipment, except those kinds which no NRTL accepts,
certifies,
lists, labels, or otherwise detemines
safe, must be "approved", as that term is defined at 29 CFR 1910.399.
Except
as
indicated in the following this
means that a NRTL must accept,certify,label,list, or otherwise detemine the
equipment is safe for it to be considered
"approved"....
Now this sounds like what the NEC code panel meant. However, it is not what
29
CFR says. Do these
"interpretations" supersede the CFR because this seems to be more than an
interpretation?
It also appears that it is up to the NRTLs to detemine what is approved and
not
approved by "accepting..." a
piece of equipment. I know a lot a listeners belong to this group. How
many
NRTL's could not find a safety"spec"
for a piece of electrical equipment? If they don't have one, why not make
one
up? This just seems a little
suspicious to me.
The altenative for "unapproved" equipment is discussed later in the letter.
This
essentially leaves it up to a Federal
Agency or State, municipal or other local athority for enforcing the
occupational safety provisions of the NEC ...
I suspect that many of the "specs" that the NRTLs use are much broader than
the
provisions of the NEC. I am not
yet familar with these provisions but do they include such things as
quarterly
audits, recertification,
notification of changes.... ?
In another letter, a slightly different approach is taken for a computer.
The
computer used in the work place is
actually considered an "appliance". Appliances are then defined in 1910.399
as
utilization equipment such as a
clothes washer, air conditioner, food mixer, deep fryer, etc... .
In general, I understand the intent is to protect the persons using the
equipment. However, this type of equipment
is generally used to perform some job function by the worker(therefore
categorizing the computer as an appliance).
This makes sense. . However, there is equipment that is not "used" to
perform
job functions.
The following example is not great but maybe somebody else can think of
something bettter. Lets say there is clock installed
on the wall with a removeable power cord. Its only purpose is for visual
indication of the time. It has been constructed
and installed according to the NEC provisions. Why does a NRTL need to
approve
it?. The installation will still need to be inspected by a local authority
to
determine if it was installed properly. Hmmmm
I imagine that sooner or latert 29 CFR will be updated to reflect the
proliferation of electronic equipment in our
work place. It just seems like a big jump from NEC to an NRTL "label" to
ensure safety in the work place. What about self declaration like CE?. It
is
much easier(at least cheaper) to maintain a TCF internally than to
coordinate
periodic audits.
And then there is liability... (maybe another time)
JIm Stafford
HPS
Product Engineer
{ these comments do not necessarily reflect the views of my employer}
