> I am in the UK, a customer in USA wants us to fit
> 2 pin mains plugs to the Class 1 appliances he
> is going to be buying from us.
>
> He is very firm that there are no regulations in US
> that requires this to be so. Is that true?
The simple answer is that there is no regulation
requiring a Class 1 appliance be provided with a
grounding-type (Class I) plug. Indeed, one can
buy a "cheater" plug (3-to-2-wire adapter) at any
electrical or hardware store. However, the use
of the "cheater" implies an independent connection
of the ground wire to a ground (which is facilitated
by the "cheater" plug). No one ever connects the
"cheater" ground to ground; in practice, it is
simply a means to connect the 3-prong plug to a
2-wire socket.
Be aware that about 1/3 of the homes in the USA
were built before the advent of the grounding-type
plug. These homes, unless remodeled, still have
only 2-wire mains sockets and wiring.
The more complicated answer is that all electrical
products in the USA must be certified for safety.
This requirement arises from two, independent sets
of regulations.
OSHA (Occupational Health and Safety Admiinstration)
regulations require electrical products used by
employees in a workplace be certified for safety.
NEC (National Electrical Code) regulations require
electrical products used in installations be
certified for safety.
Safety certifications require Class I appliances
be fitted with grounding-type mains plugs.
So, your appliance should bear a NRTL (Nationally
Recognzied Testing Laboratory) safety certification
mark. Your obligation under the safety
certification is to provide the appliance with a
grounding-type power cord and plug.
Your customer does not understand the USA safety
certification regulations (which is not particularly
uncommon).
You should explain to your customer that the fitting
of a 2-wire mains plug requires you to remove the
safety certification mark. You should then further
explain that the certification mark is required by
OSHA and NEC regulations, and that, while the
product *can* be sold without the mark, the
regulations forbid the *user* from connected it to a
source of supply.
In summary, appliance safety certification requires
a Class I product be fitted with a grounding-type
plug. Safety certification is required for
workplaces and for electrical installations (both
of which cover all possible uses of electrical
appliances).
Note that enforcement of safety certification in
electrical installations usually only occurs during
the construction and remodeling phases. Appliances
installed after such phases are not subject to
inspection, so enforcement of regulations on cord-
connected appliances is virtually zero (which doesn't
make non-certification acceptable under the law).
On the other hand, you can satisfy your customer
by altering the design such that it meets the
requirements for a Class II product. This may not
be as difficult as it first seems. If the appliance
is enclosed in metal, then all primary wiring must
be sleeved. The other mains components must be
similarly evaluated.
Best regards,
Rich
-------------------------------------------
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/
To cancel your subscription, send mail to:
majord...@ieee.org
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Michael Garretson: pstc_ad...@garretson.org
Dave Heald davehe...@mediaone.net
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
Jim Bacher: j.bac...@ieee.org
All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/ click on "Virtual Conference Hall,"
