Doug,

While I would tend to agree that this may be acceptable,
and I would too like to see some sort of 'official' 
determination on this (I may have a similar
situation arise in the next couple of months), 
I would like to play devil's 
advocate for a moment to further this discussion . . . 

As you quoted " . . . EN60950 3rd Ed., clause 2.10.1 defines
Pollution Degree 1 " for components and subassemblies which
are sealed so as to exclude dust and moisture (see 2.10.7)." 

It clearly states "for components and subassemblies". Your 
Pollution 1 argument requires the use of the IP66 enclosure. 
But is the product/enclosure pairing still considered
a 'component' or subassembly'? 
The way I see it is that the product without the enclosure
is the component or subassembly, and that installing
the product in the IP66 enclosure make the product a 
'top-level'. If for some reason the gasketing on the enclosure
fails, or it is not closed properly, the product
would not comply.

Seems risky to me?
(This is my opinion only, not that of my employer).

John Juhasz
Fiber Options
Bohemia, NY



-----Original Message-----
From: Massey, Doug C. [mailto:[email protected]]
Sent: Monday, April 02, 2001 11:47 AM
To: 'IEEE Forum'
Subject: 950 Pollution degree detirmination



Hello group -

In the -950 series standards, three Pollution Degrees are defined for
detirming insulation coordination. For instance, in EN60950 3rd Ed., clause
2.10.1 defines Pollution Degree 1 " for components and subassemblies which
are sealed so as to exclude dust and moisture (see 2.10.7)." Clause 2.10.7
gives test requirements for temp cycling, humidity, and electric strength
tests, although compliance to the clause is given as "...inspection from the
outside, measurement, and, if necessary, by test."

I would like to use Pollution Degree 1 when evaluating a product that has a
dust and water ingress rating of IP66 per IEC - 60529, Degrees of protection
provided by enclosures (IP Code) . The product itself is intended for use in
a Pollution Degree 3 environment, but the creepages and clearances inside
the unit are subject to Pollution Degree 1, thanks to the protection
provided by the enclosure.

Is the IEC-60529 report, showing a IP rating of IP66, adequate to satisfy
the requirements of 2.10.1 & 2.10.7 for using Pollution Degree 1 when
assessing clearance and creepage ?

Thanks in advance.

Doug Massey
Safety Approvals Engineer
LXE, Inc.
Norcross, GA., USA
Ph.  (770) 447-4224 x3607
FAX (770) 447-6928
e-mail: [email protected]

Cruise our website at: http:\\www.lxe.com



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