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From: emc-pstc@ieee.org on behalf of Brian
O'Connell [oconnellb@tamuracorp.com]
Sent: Thursday, August 30, 2007 1:10 PM
To: emc-pstc@IEEE.ORG
Subject: cord/plug requirements for I.T.
Good People,
I have a Class II box, that uses an IEC60320-1 inlet that will accept
both
two and three-wire cord sets. There is no ground pin in the power
inlet/coupler of the box.
Is there any requirement in NEC/CEC or 60950-1 that would not allow the
use of a three-wire cord set (line, neutral, and ground wires) with this
box ?
I have found this in UL60950-1:
"MOVABLE EQUIPMENT is considered to present a slightly increased risk of
shock, due to possible extra strain on the supply cord leading to
rupture
of the earthing conductor."
Also, section 3.2.5.1 does not disallow a three-wire cord set with a
two-pin inlet coupler.
Thanks much.
luck,
Brian
-----
From: emc-pstc@ieee.org on behalf of John Woodgate [jmw@jmwa.demon.co.uk]
Sent: Thursday, August 30, 2007 1:34 PM
To: emc-pstc@ieee.org
Subject: Re: cord/plug requirements for I.T.
In message <000d01c7eb28$a14150e0$d600a8c0@tamuracorp.com>, dated Thu,
30 Aug 2007, Brian O'Connell <oconnellb@tamuracorp.com> writes:
>I have a Class II box, that uses an IEC60320-1 inlet that will accept
>both two and three-wire cord sets. There is no ground pin in the power
>inlet/coupler of the box.
>
>Is there any requirement in NEC/CEC or 60950-1 that would not allow the
>use of a three-wire cord set (line, neutral, and ground wires) with
>this box ?
I don't know about NEC but as far as IEC/EN 60950-1 and IEC/EN 60065 are
concerned, I can see no reason to prevent the use of a three-wire
corset. In fact, if there were an issue here, the inlet with no ground
pin should not have been permitted in IEC 60320-1, because it 'invites',
or even 'encourages', the use of a normal 3-wire cord.
--
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
There are benefits from being irrational - just ask the square root of
2.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
-----
From: emc-pstc@ieee.org on behalf of rnute@san.rr.com
Sent: Thursday, August 30, 2007 1:50 PM
To: 'Brian O'Connell'; emc-pstc@ieee.org
Subject: RE: cord/plug requirements for I.T.
Hi Brian:
What is the IEC 60320-1, 2nd edition, C number for the
appliance inlet that accepts both two and three-wire
cord sets?
I reviewed the standard and could find no appliance
inlet that was either rated or configured to accept
both two and three-wire cord sets. As far as I can
tell, the two-wire and three-wire appliance inlets
and their corresponding cord connectors are mechanically
interlocked to prevent such interchangeability.
While it might be okay to use a three-wire cord on a
two-wire unit, it would not be okay to use a two-wire
cord on a three-wire unit.
So, before I can answer the question about the NEC
and CEC, I need to know the C number of the appliance
inlet. And the C numbers of both the mating two-wire
cord and three-wire cord.
Rich
Richard Nute
Product Safety Consultant
San Diego
-----
From: emc-pstc@ieee.org on behalf of Ted.Eckert@apcc.com
Sent: Thursday, August 30, 2007 2:44 PM
To: emc-pstc@IEEE.ORG
Subject: RE: cord/plug requirements for I.T.
The IEC 60320-1 C18 inlet will accept C13, C15 and C15A appliance
connectors. The system is designed to allow a higher grade connector to
be
plugged into a lower grade inlet. At one end, the C16A inlet is the most
restrictive, allowing only the grounded, high temperature C15A
connector.
At the other end of the spectrum, the C18 inlet will accept anything
from
the ungrounded C17 connector to the C15A high temperature grounded
connector.
Ted Eckert
American Power Conversion/MGE
http://www.apc.com/
-----
From: emc-pstc@ieee.org on behalf of rnute@san.rr.com
Sent: Thursday, August 30, 2007 3:13 PM
To: 'Brian O'Connell'; emc-pstc@ieee.org
Subject: RE: cord/plug requirements for I.T.
Hi Brian:
With thanks to Ted Eckert...
If the appliance inlet and the cordsets are certified
by CSA and UL, then they comply with the CEC, NEC, and
60950-1.
The interchangeability (basically an interlock system)
described by Ted Eckert limits the use of cordsets that
provide a safe connection to the mains. Certification
is validation of the safety of the interchangeability.
For maximum usability by the customer, I would recommend
supplying a two-wire C17 cordset with the equipment.
In North America, we still have homes with two-wire
outlets.
Best regards,
Rich
-----
From: emc-pstc@ieee.org on behalf of Grasso, Charles [Charles.Grasso@echostar.com]
Sent: Thursday, August 30, 2007 3:27 PM
To: Brian O'Connell; emc-pstc@IEEE.ORG
Subject: RE: cord/plug requirements for I.T.
Hi Brian - By definition a Class II box has no ground (as you
have already pointed out. Therefore the ground wire in the cord
is floating. This does not present a hazard per se as the box is
designed to meet the double insulation requirements.
(I am envisioning a moulded 3 wire cord i.e the ground wire is not
accessible to a customer)
Best Regards
Charles Grasso
Compliance Engineer
Echostar Communications Corp.
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